Concrete Rib House - Complete

TABLE OF CONTENTS PG 5 CONCRETE RIB HOUSE A CASE STUDY PG 2 INTRODUCTION PG 23 TALKING MONEY – COST STUDY OF BUILDING CONCRETE RIB HOUSES USING SPREAD SHEETS PG 25
FONDATION COST
PG 63 CONCLUSION: SHELL COST PER SQUARE FOOT PG 58
BEARING AND PARAPET BEAMS COST
PG 45
ROOF COST
PG 30
IWALLS COST
PG 105 POUTPOURRI OF SAMPLES PHOTOS OF MASONRY CONCRETE HOUSES PG 96 LIVE AND WORK CONDOMINIUMS USING CRH SYSTEM, A SOLUTIONTO ENERGY CONSERVATION PG 80 FLOOD HAZARD AREAS THE FLOATING MEZZANINE SOLUTION WITH CRH SYSTEM PG 2 ARCHITECTURAL SOLUTIONS FROM THE CASE STUDY CONCRETE RIB HOUSE PG 137 COSTA BANDERAS AN INVESTMENT AND RETURNS FOR A PLANNED RETIREMENT DEVELOPMENT PG 129 CIUDAD AZTECA – 7,500 HOUSES BUILT IN 15 MONTHS, 8 SCHOOLS, SHOPPING CENTER, OFFICES PG 117 RAMMED EARTH HOUSES HOW THE CRH SYSTEM WAS BORN PG 112 MASTER PLANS WHERE TO BUILD WITH CRH SYSTEM PG 155 GENERAL INFORMATION PG 151 ABOUT THE AUTHOR

The fast growing population is changing living conditions for people.
Land cost are forcing people to live in zones of high risk. The news often is about dwellings destroyed by natural disasters such as: fire, hurricanes, tornados, flooding, or earthquakes. Such destruction can be possible because the traditional construction system used, wood framing, is out of date to protect structures subject to the conditions in the lower cost areas where land is being developed.
After years of experience designing and building in harsh environments with strict budgets, and after living in the USA and reading the newspapers about the destruction of homes by nature, I decided to perform a case study to show a house capable of resisting the calamities described in the news. This book describes my Concrete Rib House (CRH) construction system. The CRH is durable, capable of resisting natural disasters with an affordable budget and in compliance with desired conditions of thermal performance. It uses regional materials. Construction with poured-in-place concrete minimizes the use of timber resources.
Before talking about CRH, let me analyze the cause and effect of such natural disasters.
FIRE.- Traditional construction systems based on the use of flammable materials in the exterior envelope are vulnerable to attack by burning embers. Plaster on the walls is not enough protection; embers go through openings and find places to start new fires, especially with the help of strong winds generated by topography or by weather conditions. News photos frequently show only the fireplace or other masonry element remaining in a burned house.
HURRICANES and TORNADOS.- The tradition of building houses with wood framing produces light structures; the roofs are easily lifted off by strong winds. Eaves catch the wind and the horizontal wind pressure against the windward side of the structure pushes the roof; on the leeward side, where there is no pressure, a vacuum is created; these forces working together can lift the roof off the walls. Without the roof, there is no bracing for the walls; result: the total structure collapses.
FLOODING.- Strong precipitation by itself or accompanied by hurricanes is factor for devastation. The flooding affects the wood framing, warping and damaging the structure, and rusting nails and other metal fasteners. Additional problems during flooding, such as destruction of utilities, lack of drinking water and lack of power are subjects which will be discussed in detail in the section of this book showing design solutions.
EARTHQUAKES.- Nobody knows when or how strong an earthquake will be. The typical construction solution to earthquake danger in wood framing is to reinforce corners with plywood to take the shear stress. Plywood, as a material based on a natural resource, cannot guarantee consistent quality control. This leaves a wooden structure vulnerable to seismic events.
MOLD AND TERMITES.- Again tradition is stronger than logic, dwellings built with wood framing are good to attract this pest.
INTRODUCTION

In this book I will talk about the building solutions to avoid the damage of natural disasters described above using CRH the construction system developed by me during many years of general experience in architecture and building. I have constructed several thousands of dwellings of one and two stories, schools, commercial buildings, hotels, and offices using this system. It is based on the Romans old technique - concrete poured in place. Such a technique was used more than 2,000 years ago, with many Roman structures still standing. Below is a condensed description of solutions to the devastating effects of natural disasters. Details, with text and graphics, are discussed later in this book. FIRE.- Foundation, walls and roof are all poured-in-place concrete. This structure has no exposed flammable materials. For additional protection window and door openings can have an automatic system of metal curtains. HURRICANES and TORNADOS.- The CRH system is designed to have all its elements supported by rigid pinned connections; together the foundation, walls and roof form a monolithic box structure of heavy weight. The house can have eaves and gable roofs and still keep its cohesion under strong wind forces. FLOODING.- Concrete and Styrofoam are not affected by moisture. In severe flood hazard zones the interior face of the walls will have stucco covering instead of the gypsum board used in CRH in other areas. The Design Solutions section in this book has further information. EARTHQUAKES.- An advantage of working with concrete is that there is advanced technology in structural calculations to determine the quality and stress resistance necessary for the structure to respond to specific seismic conditions. Additionally, the CRH structure uses the T-beam concept for walls and roof, arranged in such a way that the structure is braced in the “x” and “y” directions. MOLD and TERMITES.- Concrete has no organic composition for mold; and termites don’t eat concrete.

Besides being the solution for natural disasters, the CRH construction system has an economic benefit; the CRH can create jobs. CRH produces houses in a massive manner. The system is so simple that it uses many unskilled workers who with a little training become highly productive. The big volumes of construction materials make room for negotiated prices – massive construction is the key for lower construction cost and good profits. Payrolls and materials purchases make the money flow; low house prices increase sales; homeowners need new furniture and accessories; moving companies are busy; cities receive building permit and property tax revenues; offices, stores, factories, and many other businesses will need to hire more employees. People related to the development business using CRH have income and buying power. The economy goes rolling. This book will show how the CRH system can be used to build with crews of unskilled workers, in a fast mode. Concrete can be customized according to structural and budget needs; it can be molded to create any architectural decoration element to satisfy the demands of market trends. Builders can build fast, developers can sell fast, perhaps with small profits per unit but much more often. The case study was built in the Coachella Valley of Southern California (near Palm Springs), chosen considering its very high and low temperatures and its location close to the San Andreas Fault, to test power savings and earthquake structural advantages. After showing the construction process, a cost study based on the information logged during the construction process will be analyzed. Several examples of design based on the case study, samples of conceptual design of large and small dwellings, some solutions for flooding areas, and design proposal for live-and-work units will be shown. To complement, some site planning samples, one with investment and profit projections, are included from my professional work. Lastly the book includes an appendix with my experiences in search of a construction system for massive production, from prefabrication, rammed earth, masonry concrete houses, schools, and a multistory hotel.

CONCRETE RIB HOUSE A CASE STUDY The system is simple, similar to structures built by the Romans using puzzolanas (natural cement of volcanic origin) concrete. Their structures have stood for millennia and today are tourist attractions. The CRH system is similar to that of the Romans but has been updated with today’s technology, new materials, and structural engineering. The Romans used brick walls as formwork. I used plywood panels for the case study and blocks of rigid foam as formwork and insulation. Plywood could be replaced by metal or fiberglass panels to achieve a more sustainable and longer lasting formwork, avoiding use of trees to support the green building movement.

THE CONCRETE RIB HOUSE Why concrete, why ribs…? Because the concrete structure resisting loads and stress in this house is similar in function to the ribs protecting the main organs of some living creatures, including humans. The concrete ribs produce a building structure highly resistant to natural calamities such as earthquake, fire, hurricane, cyclones and flooding. Concrete is not attacked by termites or mold. In both walls and roof, the spaces between the ribs are filled with rigid foam insulation. 13 inches of this material provides an R value of 54.21. There are no leaks because the insulation is embedded in the concrete. Foundation. This is similar to a customary foundation in conventionally framed houses. The difference is that steel dowels are set in the footings to anchor the walls. These dowels function to receive the reinforcement of vertical ribs. Note the reinforcement of the stems attached to the dowels and preparation to hold roof T-beams upper and lower re-bars, as well.

WALLS The structural concept of the Concrete Rib Houses is based on the T-beam shape used to handle large spans with a minimum of concrete and steel reinforcement. The T-beam name is because its shape is a sort of capital T. The stem of the “T” would be the rib, and the crossbar of the “T” would be the flange. I use T-beams in the vertical position to create walls. For the sake of simplicity, I have not shown the steel reinforcement in the illustration at left. Two T-beams in the same line and touching creates an alcove where the insulation is embedded. The flanges in a wall create a diaphragm to resist shear stress. The insulation functions as formwork for the sides of the ribs and at the back of the flange. T-BEAM T-BEAMS ALCOVE

The sketch at the left shows one ribbed wall supporting and connected to the roof T-beam. This connection creates bracing between walls and improves the structural capacity to resist forces such as wind pressure or earthquakes. The architectural design is done to have T-beams of walls and roof in “x” and “y” directions to have bracing in all walls, keeping the “concrete box” concept unique in CRH system. Finally this sketch shows two vertical contiguous beams which create the alcove where the rigid foam insulation can be seen. The diagram shows the poured concrete walls with the embedded insulation. This system makes the insulation more effective because there are no leaks or voids, such as typically occur with insulation material installed between wood or metal framing. This concept is applicable to walls and roof. ROOF T-BEAM STEM ROOF T-BEAM FLANGE. ROOF SLAB T-BEAM IN VERTICAL POSITION CREATES THE WALL EXTENSION OF WALL FLANGE POURED WITH THE ROOF RIGID INSULATION

The construction process is shown in the photo at right. Note the dowels and the preparation for plumbing and electrical which are set in trenches under and through the footings and floor slab. The photo at left shows the vertical reinforcement of the ribs being attached to the dowels, for a T-beam wall with embedded insulation. The 3 types of walls used en this system are described on the next page. FOUNDATION ELECTRICAL PLUMBING DOWEL RIB REINFORCEMENT ATTACHED TO DOWEL

WELDED WIRE MESH USED AS REINFORCEMENT FOR THE DIAPHRAGM RESISTING SHEAR STRESS WALL CONSTRUCTION
The CRH uses three types of walls:
Type 1.- Exterior T-beam walls with embedded insulation, width per design depending of R value desired. Can be bearing or no bearing.
Type 2.- Exterior or interior walls. 6” thickness for bearing, 4” thickness for non-bearing.
Type 3.- Partition walls: steel framing, studs size per design.
A picture of the welded wire reinforcement, and the wood forming behind. ROOF STEM REINFORCEMENT WALL RIB REINFORCEMENT

At right is shown the electrical preparation on the wood forming. Above: forming of several walls in progress. Above is the rigid foam insulation in place. Note the ties in place ready to receive the forming of the opposite side of the wall. The efficiency of the thermal insulation is the result of having not leaks or voids in between the construction elements. WALLS – continued

Insulation in all required walls following the building plans as lines drawn on the slab by the forming crew. After placement of insulation, reinforcement and forms, the concrete is poured to the top of the walls. WALLS – continued The next step is placing the rigid insulation following the previously marked location of the walls, as shown below (top left). The other s ketches show the sequence of setting insulation and pouring walls.

At left exterior view of rigid insulation showing electrical ducts which will be embedded in concrete. Above interior view insulation covered by interior forming. Note the reinforcement for the roof stems . At left is a detail of dobies serving to hold the insulation as well keep the diaphragm at the thickness required by the structural calculations. Photo sequence of setting insulation

At left: Once the forming has been finished, the next step is pouring the walls with premix concrete delivered by pumping. This picture shows the pouring of the walls all the way to the top. Note the steel reinforcement to be used for the parapet walls, which will be poured later at the same time as the roof structure. At the lower left of the picture a window is shown set in place. When the walls are poured, the window will be held by concrete. The efficiency of the thermal insulation lies in eliminating leaks or voids in between the construction elements. The picture at right shows the removal of the forms and the surface on the face of the wall. This wall is an interior bearing wall 6” thick, which will carry T-beams in the direction of the re-bars. The T-beams on top of the area behind the opening will be north-to-south. These will combine with east-west axis beams to provide the greatest earthquake resistance. Pouring walls

Roof - diagrams of placing insulation and pouring concrete Note that supports holding the blocks of rigid insulation and the reinforcement of the ribs (flanges) are not shown. These can be seen in the first photo on page 16. Fast setting pre-mix concrete is placed by pump, as shown in the photo on page 17. Fast setting concrete is used to enable the roof forms to be removed quickly, to expedite further phases of the construction such as applying the gypboard and building the partition walls.

The forming to pour the roof is special because it is not necessary to form the entire bottom of the roof area. It is only necessary to support the bottom of the stems of the T beams which also serve to support the rigid insulation. These supports are lumber strips which are held up by vertical adjustable-height steel posts. At left the worker is adjusting a piece of insulation to be set. Above right is a photo of an opening for a skylight. Note the reinforcement and the metal nailers that will hold the ceiling gypsum board. Also note the T-beams set at right angle directions to work bracing each other.

Pouring the roof using pre-mix concrete set by pump. The roof pouring was done by a crew of 4 men on the roof plus one on the ground controlling the pump. They poured 2,200 square feet of roof in one day. Forming posts and beams were previously placed, and the rigid insulation and the stems steel rebar reinforcement done. Note that these T-beams are meant to work as bracing in one direction (east to west in this case). The T-beams on top of the area behind the opening will work as bracing at a right angle (north to south). This design gives the most resistance to earthquakes and wind pressure.

The savings in labor makes the Concrete Rib House system very competitive, and the strictly controlled quality delivers a great product. In the photo above a stem is visible at the edge of an opening for a sky dome, as well as the bottoms of stems between the rigid insulation. The centers of the stems have a steel stud embedded which will be used to attach the gypsum board for the ceiling. A similar solution is used in the center of the ribs in the walls for attaching the gypsum board wall finish. This enables the builder to meet the expectations of the market regarding the appearance and use of walls. The difference between this and a stick-built house will become apparent only during a fire when the CRH does not burn, or during a tornado when the roof does not blow away.

Living room Master bedroom Interior final appearance

kitchen Granite counter

Access path to the main entry.
Side yard entry court; note the corner window.
The casita separate entry.
Patio with special fabric shaded trellis creates a relaxed atmosphere to enjoy the landscape and entertain friends. To increase fire resistance the columns and trellis can be built with vinyl elements, which will melt but will not create flames. No exterior surface of the house is flammable; contents such as memorabilia and furniture will be safe. 1 3 2 Exterior appearance

Concrete Rib House at night At night the house is vibrant in the dark. The owners of this house will sleep with no worries of earthquakes, fires, hurricanes, tornados, or other natural disasters. They are protected by the rib structure built with concrete as used around 2,000 years ago by the Romans whose structures still stand today as tourist attractions. Concrete is a material which allows strict quality control since the technology permits calculation of the strength required according to function, environmental circumstances and budget. Wood, as a natural product, does not offer the same control. The case study shows a house in the Desert Modern style, but this construction system easily accommodates any architectural style. Refer to the potpourri of samples section.

TALKING MONEY: A cost study of building Concrete Rib Houses $ The greatest economic success in building houses using the Concrete Rib House method occurs when multiple units are produced with the same set of formwork. This cost study assumes 40 uses of one set of formwork, and will show a great competitive value, considering the high quality of the building structure. The prices used in this study are actual cost in California in the year 2007, the construction year of the CRH case study. Costs are generated using the logged prices for materials and labor. The labor costs unique for the CRH were established by observation of the time required for each task and using the workers’ hourly rates. In the case of processes common to conventional construction (for example foundation and stucco finish) the cost was negotiated at local market rates. The cost shown in the study are not marked up and do not include profit, taxes, worker insurance, travel expenses.

PROCESS TO OBTAIN UNITARY COSTS
On the following pages you will find spread sheets for the basic elements to build a structure with the CRH method. The studies by experience by building the case study have green headers. The ones related to conventional construction: yellow and light blue headers.
When referring to structural conditions, you will find structural drawings with floor plans, details, sections, as required for information.
The cost studies are only for basic elements to build by CRH method, finishing materials (flooring, stucco. paint, as a sample), plumbing including kitchen and bath fixtures, electrical, air conditioned and other special materials or installations will be per market values.
The basic costs for the CRH shown are:
FOUNDATION - The foundation of the CRH is done as in conventional construction, except for the use of dowels to receive the structural reinforcement for the exterior walls.
WALLS - This phase of the construction is one of the basic elements of CRH method.
ROOF - This phase is also a basic element of CRH method.
Foundation, walls and roof are the core which makes the CRH method capable of resisting natural disasters. Finishing, equipment and appliances are as required by specifications, market costs.

FOUNDATION
The cost study is based on the experience when building the CRH case study.
Page 26 shows the construction foundation floor plan of the CRH case study.
Page 27 has the structural construction details depicting dimensions and reinforcement obtained by structural calculations in compliance with the governing codes and regulations of the City of Cathedral City.
Page 28 and 29 show spread sheets template using the information contained in pages 26 and 27.
The labor was provided by a concrete contractor working at a flat fee using his own equipment.
The material was bought as a separate item.

FOUNDATION FLOOR PLAN

FOUNDATION STRUCTURAL DETAILS

Table headers, yellow fill, calculations to find volume of concrete required: axis – Letters correspond to labels of the axes on the floor plan on page 26. between – Axis segment is located between the axes at right angles. See floor plan on page 26 type - Detail of foundation with dimensions and reinforcement required by details shown in sheet S3 on page 27. base in - Dimension of the base from sheet S3 on page 27 by detail type. height in - Dimension of the height from bottom to finish floor as shown sheet S3 page 27. by detail type. area in2 - Area of the foundation section in square inches (the product of Base by Height). length ft - The length dimension in feet and inches, per sheet S2 page 26. length in - The translation of the length from feet and inches to inches. volume in3 - The volume in cubic inches as the product of Area square inches by Length inches. volume CY - The volume in cubic inches divided by 45,656 (cubic inches in a cubic yard) to convert the cubic inches to cubic yards as used to order premix concrete Table headers, blue fill, calculations to find the re-bars for reinforcement, as noted in details sheet S3: rebar - Specifications of the re-bar type per diameter, and number of re-bars called in the details on S3 for reinforcement. length in – Total length in inches of re-bars reinforcement. pc of 20ft – Quantity of 20-foot re-bars, as commercially available in the market. The length in divided by 240 (12*20). FOUNDATION COST

Table above left: dowels as shown in details on S3 – page 92.
Table above right, shows area calculations of the areas shown in sheet S2 on page 91.
Table lower right is the total of materials and labor required to build the foundation footings and floor slab for a house such as the Concrete Rib House depicted in this book. The unitary costs are as California Market in 2007. For updating use current costs in the location of the construction site being studied.
FOUNDATION COST

WALLS
In the case study of the Concrete Rib House different wall types were used, according with their function. For locations of each type, refer to floor plan S4 on page 31 and structural details on page 32.
T-WALL TYPE A (see detail 1 on Sheet S5 on page 32) – This wall has a shape of a T-beam but in vertical position, the stem of the T is named in here “Rib” because its protective function and its use define the why the Method is named Concrete Rib House. The Ribs and the diaphragm slab encased the rigid insulation, used by blocks in the dimensions required by design. The Rib end hold metal nailers which let attach drywalls panels. These walls are used at exterior perimeter locations for living areas. This cost study is for 16 inches wall thickness. Exterior walls can be any thickness weather conditions and or budget will be decision factors.
UNRIBBED WALL TYPE B (see detail 2 on page 32) – This walls have a rectangular foot print. Are used to enclose no living areas, or in locations not exposed to the exterior at living areas. Normally are used for bearing load walls, but can be partition walls. The face to have gypsum board panels will be have encased metal nailers. This cost study is for 6 inches thickness.
WOOD OR METAL FRAMED WALL TYPE C (see detail 3 on page 32) – P artition walls at market cost.
The cost study will analyze the formwork used for A and B wall types. Items to hold wallers can be use over 40 times, but in the cost 40 times is the factor. The snap ties type are specific for the wall thickness. Cost of stucco, nailers, gypsum board, insulation, concrete, pumping and labor included in wall type A. Wall type B includes the same except insulation, gypsum board and or stucco only when specified. The costs have different values for such variances.

FLOOR PLAN SHOWING WALL TYPES

STRUCTURAL DETAILS 1, 2, 3 FOR WALLS

The formwork material and labor cost is the same for any thickness of wall. What defines the wall thickness are the dimensions of the ties used. In this study 6” and 16” ties will be considered. FORMWORK COST

There is an additional cost of forming material used to hold the formwork to the concrete floor slab such material is per use. ACCESSORIES SNAP TIES Snap ties holding the two panels of the formwork are per use. Cost to be added.

STUCCO COST Dimensions correspond to the floor plan on page 31. The length of the wall segment of each axis was multiplied by the height, which includes the wall and the parapet. These segment areas were added to obtain a total (A). The flat fee contracted for the case study house, which included labor and material, was divided by the total square feet. The cost gives the average cost per square foot of stucco. Note that the price for stucco on a “standard” 8-foot high wall would be $ 8.72 per linear foot.

NAILERS Gypsum board (drywall) panels are used to face the interior of the walls because this is what consumers expect. In order to have an effective nailing surface (other than concrete) to hold the gyp board, the CRH method uses nailers of 1.5/8” metal studs with a backing of Styrofoam set into the formwork to be embedded in concrete during pouring. Patent Pending. One nailer along the stem of each rib. Ribs are 24 in on center. When the face of a wall 6 in thick will be covered with drywall, nailers are used. The cost analyzed is per linear foot of wall.

INSULATION Work of hanging drywall on the walls was negotiated at a flat fee, including labor, materials, taping and texturing. The table on age 56 contains detail used to establish cost of walls. GYPSUM BOARD CONCRETE $ 0.58 SF

These costs include labor and materials such as rebar, pencil rods, wire mats, and wire ties per structural calculations. REINFORCEMENT

PLACING FORMWORK Placing formwork for 6-inch walls and 16-inch walls are similar. 16in walls have the rigid insulation placed using metal angles and dobies in coordination with the reinforcement steel.

CONCRETE POURING This phase of the construction uses a team of concrete workers using a concrete pump and vibrator. The pump is rented. The vibrator and scaffolds are included in the concrete sub-contractor fee.

TOTAL CONSTRUCTION COST OF WALLS Using the values obtained in the cost studies in the page noted from the table at right, the different cost for each one of the walls used in the CRH Case Study will be shown on the following pages. 11.30 LF/8' ht 105 Concrete pouring 16in wall 15.78 LF/8' ht 105 Concrete pouring 6in wall 4.76 LF/8' ht 104 Placing formwork for 16in wall 3.60 LF/8' ht 103 Placing formwork for 6in wall 5.96 LF/8' ht 103 Steel reinforcement 16in wall 6.99 LF/8' ht 102 Steel reinforcement 6in wall 5.47 LF/8' ht 102 Concrete 16in wall 14.28 LF/8' ht 102 Concrete 6in wall 22.85 LF/8' ht 102 Insulation 0.80 SF 102 Gypsum board 1.32 LF/8' ht 101 Nailers 16in wall 1.32 LF/8' ht 101 Nailers 6in wall 1.09 SF 100 Stucco 3.00 LF/8' ht 99 Snap ties 16in wall 1.26 LF/8' ht 99 Snap ties 6in wall 0.48 LF/8' ht 99 Formwork accessories 1.40 LF/8' ht 98 Formwork $ UNIT page DESCRIPTION 11.30 LF/8' ht 40 Concrete pouring 16in wall 15.78 LF/8' ht 40 Concrete pouring 6in wall 4.76 LF/8' ht 39 Placing formwork for 16in wall 3.60 LF/8' ht 38 Placing formwork for 6in wall 5.96 LF/8' ht 38 Steel reinforcement 16in wall 6.99 LF/8' ht 37 Steel reinforcement 6in wall 5.47 LF/8' ht 37 Concrete 16in wall 14.28 LF/8' ht 37 Concrete 6in wall 22.85 LF/8' ht 37 Insulation 0..58 SF 37 Gypsum board 1.32 LF/8' ht 36 Nailers 16in wall 1.32 LF/8' ht 36 Nailers 6in wall 1.09 SF 35 Stucco 3.00 LF/8' ht 34 Snap ties 16in wall 1.26 LF/8' ht 34 Snap ties 6in wall 0.48 LF/8' ht 34 Formwork accessories 1.40 LF/8' ht 33 Formwork $ UNIT page DESCRIPTION

TYPE A – RIBBED WALL WITH INSULATION 69.79 LF/8' ht TOTAL 6"wall 8' height 6.40 0.80 SF Stucco 8 8.72 1.09 SF drywall 8 11.30 11.30 LF/8' ht Concrete pouring 6 in wall 1 5.47 5.47 LF/8' ht Concrete 6x12x96 inches 1 6.99 6.99 LF/8' ht Steel reinforcement 6 in wall 1 1.32 1.32 LF/8' ht Nailers 6 in wall 1 1.26 1.26 LF/8' ht Snap ties 6 in wall 1 22.85 22.85 LF/8' ht Insulation 1 3.60 3.60 LF/8' ht Placing formwork for 16 in wall 1 0.48 0.48 LF/8' ht Formwork accessories 1 1.40 1.40 LF/8' ht Formwork 1 TOTAL UNITAR Y PRICE UNIT DESCRIPTION Q STUDY COST OF WALL 16" drywall/stucco 65.71 LF/8' ht TOTAL 6"wall 8' height 6.40 0.80 SF Stucco 8 4.64 0.58 SF drywall 8 11.30 11.30 LF/8' ht Concrete pouring 6 in wall 1 5.47 5.47 LF/8' ht Concrete 6x12x96 inches 1 6.99 6.99 LF/8' ht Steel reinforcement 6 in wall 1 1.32 1.32 LF/8' ht Nailers 6 in wall 1 1.26 1.26 LF/8' ht Snap ties 6 in wall 1 22.85 22.85 LF/8' ht Insulation 1 3.60 3.60 LF/8' ht Placing formwork for 16 in wall 1 0.48 0.48 LF/8' ht Formwork accessories 1 1.40 1.40 LF/8' ht Formwork 1 TOTAL UNITAR Y PRICE UNIT DESCRIPTION Q STUDY COST OF WALL 16" drywall/stucco

TYPE B – UNRIBBED WALL UNRIBBED WALL TYPE B (see detail 2 on page 32) There are different costs regarding the material used to cover the faces. 60.23 LF/8' ht TOTAL 6"wall 8' height 6.40 0.80 SF Stucco 8 8.72 1.09 SF drywall 8 15.78 15.78 LF/8' ht Concrete pouring 6 in wall 1 14.28 14.28 LF/8' ht Concrete 6x12x96 inches 1 6.99 6.99 LF/8' ht Steel reinforcement 6 in wall 1 1.32 1.32 LF/8' ht Nailers 6 in wall 1 1.26 1.26 LF/8' ht Snap ties 6 in wall 1 3.60 3.60 LF/8' ht Placing formwork for 6 in wall 1 0.48 0.48 LF/8' ht Formwork accessories 1 1.40 1.40 LF/8' ht Formwork 1 TOTAL UNITAR Y PRICE UNIT DESCRIPTION Q STUDY COST OF WALL 6" drywall/stucco 56.15 LF/8' ht TOTAL 6"wall 8' height 6.40 0.80 SF Stucco 8 4.64 0.58 SF drywall 8 15.78 15.78 LF/8' ht Concrete pouring 6 in wall 1 14.28 14.28 LF/8' ht Concrete 6x12x96 inches 1 6.99 6.99 LF/8' ht Steel reinforcement 6 in wall 1 1.32 1.32 LF/8' ht Nailers 6 in wall 1 1.26 1.26 LF/8' ht Snap ties 6 in wall 1 3.60 3.60 LF/8' ht Placing formwork for 6 in wall 1 0.48 0.48 LF/8' ht Formwork accessories 1 1.40 1.40 LF/8' ht Formwork 1 TOTAL UNITAR Y PRICE UNIT DESCRIPTION Q STUDY COST OF WALL 6" drywall/stucco

TYPE B – UNRIBBED WALL 62.55 LF/8' ht TOTAL 6"wall 8' height 17.44 1.09 SF drywall 16 15.78 15.78 LF/8' ht Concrete pouring 6 in wall 1 14.28 14.28 LF/8' ht Concrete 6x12x96 inches 1 6.99 6.99 LF/8' ht Steel reinforcement 6 in wall 1 1.32 1.32 LF/8' ht Nailers 6 in wall 1 1.26 1.26 LF/8' ht Snap ties 6 in wall 1 3.60 3.60 LF/8' ht Placing formwork for 6 in wall 1 0.48 0.48 LF/8' ht Formwork accessories 1 1.40 1.40 LF/8' ht Formwork 1 TOTAL UNITAR Y PRICE UNIT DESCRIPTION Q STUDY COST OF WALL 6" drywall/drywall 54.39 LF/8' ht TOTAL 6"wall 8' height 9.28 0.58 SF drywall 16 15.78 15.78 LF/8' ht Concrete pouring 6 in wall 1 14.28 14.28 LF/8' ht Concrete 6x12x96 inches 1 6.99 6.99 LF/8' ht Steel reinforcement 6 in wall 1 1.32 1.32 LF/8' ht Nailers 6 in wall 1 1.26 1.26 LF/8' ht Snap ties 6 in wall 1 3.60 3.60 LF/8' ht Placing formwork for 6 in wall 1 0.48 0.48 LF/8' ht Formwork accessories 1 1.40 1.40 LF/8' ht Formwork 1 TOTAL UNITAR Y PRICE UNIT DESCRIPTION Q STUDY COST OF WALL 6" drywall/drywall 53.83 LF/8' ht TOTAL 6"wall 8' height 8.72 1.09 SF drywall 8 15.78 15.78 LF/8' ht Concrete pouring 6 in wall 1 14.28 14.28 LF/8' ht Concrete 6x12x96 inches 1 6.99 6.99 LF/8' ht Steel reinforcement 6 in wall 1 1.32 1.32 LF/8' ht Nailers 6 in wall 1 1.26 1.26 LF/8' ht Snap ties 6 in wall 1 3.60 3.60 LF/8' ht Placing formwork for 6 in wall 1 0.48 0.48 LF/8' ht Formwork accessories 1 1.40 1.40 LF/8' ht Formwork 1 TOTAL UNITAR Y PRICE UNIT DESCRIPTION Q STUDY COST OF WALL 6" exposed/drywall 49.75 LF/8' ht TOTAL 6"wall 8' height 4.64 0.58 SF drywall 8 15.78 15.78 LF/8' ht Concrete pouring 6 in wall 1 14.28 14.28 LF/8' ht Concrete 6x12x96 inches 1 6.99 6.99 LF/8' ht Steel reinforcement 6 in wall 1 1.32 1.32 LF/8' ht Nailers 6 in wall 1 1.26 1.26 LF/8' ht Snap ties 6 in wall 1 3.60 3.60 LF/8' ht Placing formwork for 6 in wall 1 0.48 0.48 LF/8' ht Formwork accessories 1 1.40 1.40 LF/8' ht Formwork 1 TOTAL UNITAR Y PRICE UNIT DESCRIPTION Q STUDY COST OF WALL 6" exposed/drywall

ROOF
.
The Microsoft Office Excel generated tables analyze labor and materials per square foot of roof of the CRH structure in the study:
Formwork and pipes used for shoring are rented. Beams and boards cost to be prorated by 40 uses, are in page 48.
Labor and accessories for formwork on page 49.
Labor for stems and flange reinforcement and placing block insulation on page 52.
Rebar, mesh and metal nailers material on page 53.
The rigid insulation blocks and mesh to reinforce the top slab (T-beam’s flange) on page 54.
Fast set concrete used in roof to reduce the construction time on page 54.
Drywall used in ceilings and walls are discussed on page 56.
Roofing labor and materials on page 57.
The cost study uses direct costs of the elements used for the roof structure as shown in the list below. Refer to the plan and structural details on pages 46 and 47.

ROOF PLAN SHOWING POSTS AND BEAMS FOR FORMWORK

ROOF STRUCTURAL DETAILS

The rental of shoring pipe is cost effective because it includes the delivery and return to the renting company. The pipes do not need to be stored or maintained. Minimal investment is necessary. In the case study 129 shoring pipes were used for the roof of 2850 SF. Cost is shown at the Table at left. Beams and boards are supported by the shoring pipe. These serves to hold the concrete in the ribs as well as the rigid insulation between the ribs. Beams and boards need to be purchased. The cost study assumes 40 uses of a set of beams and boards, averaging the cost, as shown here.

Labor involves placing the shoring pipes and putting the 4x8 wood beams on the pipe heads to receive the 2x8 boards. The boards are nailed to the beams, and serve to brace the formwork, facilitating the placing of nailers which will serve to hold the drywall ceiling. These tasks are simple and do not require special skills; entry level construction laborers can do this with no problem. The table at the right shows the total rebar numbers used to build the case study following the structural calculations reflected on pages 112 and 113. The following pages detail the process of obtaining these totals. Costs for additional components of the roof will be shown in the following pages.

Different design conditions make the supporting walls of the roof different. At left we have the study of a roof supported on 6” walls at both ends. The table at right shows the roof T-beams to be supported by a 6” wall in one side and a 16” wall on the opposite side.

The tables on page 50 and 51refered to T-beam types are as structural details in page 47, as well mesh reinforcement. Note than the structural documents use the word joist for the T-beams. The table at right shows the welded wire mesh 6x6 – w2.5xw2.5 used for beam stem as stirrups and steel reinforcement of the beam flange. The table also shows the amount of concrete in cubic yards used to build the roof of the Case Study Concrete Rib House,

The table at left shows time used to cut and assemble rebar, wire mesh, stirrups and pencil rod. Another laborer places the reinforcement in the formwork after setting the nailers in place, and another worker places the block insulation and puts wires and 2x2 metal angles to hold the blocks in place. The times are averages obtained by observation of 3 laborers during 8 hours work. Once the reinforcement of the ribs (stems) and insulation, is in place, a worker lays wire mesh on top overlapping 12 inches and tying the mesh with wire; special 2x2-inch dobies are used to keep the mesh reinforcement centered in the two inches slab thickness. The time was averaged by observation of crew doing the job.

The table above shows cost calculations of steel reinforcement for ribs (stem) of the T-beams including the nailers which are set by the laborers during the same phase of placing the stem reinforcement. The table at right shows calculations for bottom of ribs. Table on next page calculations of total length of ribs – refer to floor plan in page 46 for information.

The T-beam flange once poured becomes the top of the roof as a continuous slab. The T-beams have supports at the heights which can provide slopes of a minimum of ¼” per foot. Crickets can be built to direct water on a flat roof toward the gargoyles. Parapet walls and concrete beams will be the complement of the roof structure, being studied as a separate section.

Construction speed is important to minimize cost of construction loans. The CRH, as a system to produce buildings in large numbers, uses fast set concrete to reduce the setting time of concrete from the standard 28 days to only 3 days. Using fast set concrete, the formwork for the roof is soon moved to the next building, allowing the next phase of construction to continue. For competitive quality and price the concrete used to build the roof had fiber glass mesh in the mix. The cost was recorded from pouring of 40 CY during the construction of the case study CRH.

This page shows the detail of the walls and ceiling faced with drywall. The difference in cost between wall and ceiling were obtained by observation of the process .

The roof waterproofing job was a flat cost negotiated for a high quality including the parapet walls, the skylights bases, cold to primer roof holding single fiberglass base #75. Torch down polyglass modified, corners sealed with roof cement and granules. ROOF CRH DIRECT COST $ 16.70 / SF 16.70 Direct Cost of Roof CRH method per SF . 122 3.01 SF Labor and material - roofing 121 0.87 SF Labor and material - drywall on ceiling 120 5.09 SF Fast set concrete: material, labor setting, pumping 119 0.96 SF Material reinforcement for T - beam flange (slab cover) 119 5.04 SF Rigid insulation blocks 118 0.50 SF Material reinforcement for T - beam stem includes nailers. 117 0.05 SF labor reinforcement flange T - beam Rib (stem) 117 0.56 SF Labor stems reinforcement and placing insulation 114 0.43 SF Cost per SF labor and accessories to set formwork 113 0.02 SF Beams and boards roof formwork (40 uses) 113 0.17 SF Cost per rental pipe shore See PAGE $ UNIT DESCRIPTION 16.70 Direct Cost of Roof CRH method per SF . 57 3.01 SF Labor and material - roofing 56 0.87 SF Labor and material - drywall on ceiling 55 5.09 SF Fast set concrete: material, labor setting, pumping 54 0.96 SF Material reinforcement for T - beam flange (slab cover) 54 5.04 SF Rigid insulation blocks 53 0.50 SF Material reinforcement for T - beam stem includes nailers. 52 0.05 SF labor reinforcement flange T - beam Rib (stem) 52 0.56 SF Labor stems reinforcement and placing insulation 49 0.43 SF Cost per SF labor and to set formwork 48 0.02 SF Beams and boards roof formwork (40 uses) 48 0.17 SF Cost per rental pipe shore See PAGE $ UNIT DESCRIPTION

BEARING & PARAPET BEAMS Bearing beams are shown on page 59 as types A, B1, B2, C, and D. Details of section dimensions and reinforcement are on page 60. Bill of materials and labor is shown in the tables on the same page. Beams forming part of the parapet walls are shown in the plan on page 61. Spans of parapet walls that receive a load greater than the acceptable by the standard section and reinforcement are also detailed on page 61. Price established on page 62. A summary of bearing and parapet beams is on page 62, table at lower right.

BEARING BEAMS PLAN AND DETAILS

The cost study was calculated using reinforcement per LF and a layer of concrete one inch deep by 6” wide x one LF. With the above criteria the cost of each beam type required by structural calculations is shown in the table at right.

PARAPET BEAMS PLAN AND DETAILS

BEARING AND PARAPET BEAMS PER LF Above studies of parapet beams as shown in floor plan and details in page 126. The differences in reinforcement and dimensions were per loading conditions. For example, parapet Beams E and E1 are supporting the garage roof at the span of garage doors. 127 9.54 LF Cost per parapet beam F to F4, G, H, J, K to K2, L & M 127 14.58 LF Cost per parapet beam E 125 36.27 Pc Cost per beam type D material & labor 125 44.08 Pc Cost per beam type C material & labor 125 52.86 Pc Cost per beam type B1, B2 material & labor 125 95.97 Pc Cost per beam type A material & labor See PAGE $ UNIT DESCRIPTION 62 9.54 LF Cost per parapet beam F to F4, G, H, J, K to K2, L & M 62 14.58 LF Cost per parapet beam E 60 36.27 Pc Cost per beam type D material & labor 60 44.08 Pc Cost per beam type C material & labor 60 52.86 Pc Cost per beam type B1, B2 material & labor 60 95.97 Pc Cost per beam type A material & labor See PAGE $ UNIT DESCRIPTION

Using the information from pages 90 to 127 a cost of the Case Study shell is shown below. Remember this cost is an average assuming construction of 40 units. More or fewer units will affect the results; generally the cost will be lower if more than 40 units are built, and will be greater when fewer than 40 units are built. The cost is DIRECT COST with no contractor’s mark up, workers compensation, overhead, taxes, or whatever can be added for the working conditions, location, weather, etc. To work in a budget use the square foot cost of the sell by the build area and add the elements as windows, plumbing, electrical, finishing, etc. also add contractor mark up and building permit, and play with such numbers to reach the desired budget amount.

SAMPLES BASED ON THE CASE STUDY
The following pages illustrate how using the set of forms from one house, Model 1, it is possible to reuse the set in different configurations to produce many different designs, Models 2, 3, to Model x.
This flexibility is a plus for developers.

FLOOR PLAN OF THE CASE STUDY HOUSE

FLOOR PLAN MODIFIED # 1 3 car garage , laundry, mechanical, foyer, 3 bedrooms, bath, master bedroom, master bath, walk-in closet, kitchen, dining, living, and terrace.

MAIN ENTRY DETAIL From floor plan modified # 1

FROM FLOOR PLAN MODIFIED #1 Entry, foyer, living, dining, kitchen terrace.

BREAKFAST COUNTER, DINING Floor plan modified # 1 .

FLOOR PLAN MODIFIED #1 Terrace , note the corner window and the receded windows and doors. Also the precast sill and headers, features for the CRH innovative construction system.

FROM FLOOR PLAN MODIFIED #1 Master bedroom, master bath, walk-in closet, the thickness of the exterior walls result of the rigid insulation embedded: characteristic of the Concrete Rib House Construction System.

FLOOR PLAN MODIFIED #1 Bathroom detail

FLOOR PLAN MODIFIED # 2 Shows the living area similar to the Modified 1, but with 2 car garage and the main entry facing the street, details of Modified 1 applied to this, plus the three following sketches.

Kitchen detail at modified 1 and 2, showing the pantry area and the serving the breakfast counter.

Kitchen detail view #2 at modified 1 and 2, showing the pantry area and the serving the breakfast counter.

Laundry room detail at modified 1 and 2, also shows the tub at bath and the guest closet at Foyer.

MODIFIED 3. 4 bedrooms, 2 car, with loggia facing the street the living area is similar as Modified 1 and 2. Details of living area applied to all of them .

OPTION 4 – 3 bedrooms 2 car garage Dimensions similar at the previous shown, only one bedroom less and garage shorter by three feet, has a nice loggia facing the street.

FLEXIBILITY
The reuse of formwork, generally up to 40 uses for plywood, can change the arrangement of the spaces providing many different models of houses to give many options to buyers.
The design is not limited to one story. The reuse of the formwork can be applied to two or more stories.
Formwork can be done to create any texture or detail as moldings, trims or any gingerbread as desired or required by architectural style or innovation in design, fiberglass or similar materials can achieve the negative shape to mold the concrete. This process can produce very elaborated forms by the time of pouring the concrete with not expensive labor involved.
Design by modules can make the reuse of the formwork with out having to build 40 units to make effective the system.

FLOOD HAZARD AREAS The floating mezzanine solution This design, for people living in flood hazard zones, enables them to stay safely in their homes, retaining belongings, pets, etc., and avoiding the need to be evacuated. The key is a floating upper floor, with all the basics for living, including drinking water from a built-in reservoir collecting rain water with a purifier device, will be provided to survive the days of isolation. Note: water lines contamination is probable under flooding conditions.

A water reservoir is the core providing service to the fixtures directly by straight connections in the first floor and collapsible connections to the floating area. In normal conditions services are provided by the local utilities. In emergency conditions water can be obtained by rain, and purified for drinking, bathing and cooking Foundation built by conventional methods. Tank reinforced concrete poured in place.

The ground level has laundry room, guest closet, powder room, full kitchen with breakfast counter, and spacious area for living dining and family activities. The sketch is shown with partial walls for clarity.

This image shows the core reservoir and the mezzanine with exterior walls before installing the drywall to show the rigid insulation embedded in concrete. Walls in the first level omitted.

This sketch shows the 3 basic elements: foundation, reservoir tank and the floating mezzanine.

Here the mezzanine is shown floating per Archimedes principle. The volume of the rigid foam is calculated to carry the loads of the mezzanine deck.

Ground level showing the foyer with the stairs and at rear the 2 car garage. The beams on columns support the mezzanine, which remains in place by gravity.

Detail of the powder room with access to the laundry room, no doors shown for clarity, no drywall in place to show the rigid insulation in the walls.

This image shows the full kitchen in the ground floor. Note all fixtures requiring water are against the reservoir tank wall, this saving on plumbing tubing costs.

Foyer detail showing stairs

Mezzanine floor plan showing the emergency kitchen. The wall nearest the reservoir is framed to allow space for free movement of the collapsible hoses when flooding occurs. This keeps the water running in the faucets of the fixtures with no interruption. Roofs of the garage and foyer shown. Drywall panels are not shown to give idea of how exterior walls are insulated. Master bedroom plus two standard bedrooms shown.

Emergency food storage is contained in the refrigerator attached to the wall of the floating Mezzanine by a mechanism which allows movement to be reach under flooding conditions.

Detail of bathroom on mezzanine, note the separation between framed wall and concrete tank wall of the reservoir. This allows movement of the hoses connecting to the water supply during flooding conditions.

The illustration at right shows the construction of the mezzanine deck, using metallic trusses holding rigid foam blocks and supporting the flooring plus the partition walls, furniture and live loads. The volume of the foam is calculated to float with all the loads in the flooding. The corners of the mezzanine have rolling devices to allow the vertical movement. At left a detail of one connection by collapsible hoses in between the reservoir tank and a faucet, the collapsible hose lets free vertical movement keeping the service uninterrupted. Water in normal conditions services are provided by the local utilities. In emergency conditions water can be obtained by rain, and purified for drinking, bathing and cooking.

. The use of solar panels is another feature to allow the people in the house to have power for the light and kitchen fixtures in emergency situations.

Street view of the proposal for a Concrete Rib House with floating mezzanine. Using this design concept can produce infinite solutions, even one story houses with the flooring on a structure like the mezzanine shown on page 94.

LIVE and WORK
The dependence on oil has created the need to seek other sources of energy. Meanwhile it is wiser to reduce our use of petroleum products such as gasoline. Driving to work is eliminated when all you have to do is go downstairs to be at the work place. Live and Work condo units can be easily produced because the CRH system is ideal for the mass production required by such developments.
Photovoltaic elements will serve besides to “fill the tank” of the automobiles likely to be soon in available in the market for owning one.

The units are similar the differences are only in the walls types 6 in thick walls shared by two contiguous units. In the rendered ground floor shows an end unit, the shared wall is labeled, as well the use of the areas/
This sample shows a possible musical store
6 in common wall Garage, storing and laundry Stairs to mezzanine 2 double doors entries to the store Store front windows

Detail corner showing one entry double door, the cahier station, merchandise for sale, the top of the stair. The interior face of the walls are ready to be gyp board walled, except one in the garage/store area to show the appearance after dry wall applied – the CRH system looks like the traditional framed walls - Top of door to the powder room for clients convenience.

This is an areal view of the ground floor with the concrete slab mezzanine in place and shows the stair in its stairs well

For clarity first the rendering shows the two bedrooms, the two closets and the bathroom with doors to each bedroom also the stair going to the roof garden is shown At right a detail of the shared bathroom of the bedrooms with the door of bedroom one shown., some walls removed for clarity.

At right detail of the living room, the kitchen area with hard floor for the service work, also in the bottom right of the sketch partial of dining area in the foreground the stair going to the roof garden are shown. The low walls and windows to complete the façade are shown with no drywall board applied to show the encased rigid insulation characteristic of the CRH system. This two views are showing the dining area, the one at left has the door of bedroom one and the start of the stair, the view at right shows the guardrail wall facing the store area. The opening of the living and dining areas to the store makes convenient for the store owner to rest pleasantly when are not costumers in the store.

At left an overview of the slanting roof covered with solar panels to provide for electric power for the condo needs and to “fill the tank” of the future electric car. Also the green area for landscaping or growing vegetables to have a fresh salad when wished. A concrete build in spa to enjoy the sky view in a relaxing worm water. A terrace area to have table and sitting to have snacks and a cup of coffee. At left a detail of the comfort area terrace and spa, the door to the stairs well is shown at right of the picture

Some additions such as stair lifts, grab bars and wider doors, can be used to accommodate handicapped persons to occupy Live and Work units.

Some shots of the vending area to convey information how an unit can display for business, which can be any use: ice cream stores, artist galleries, bicycle shop, beauty saloon, law or dentist, real estate or any other office. You name what you need is. Live up, work down and relax at the top….

Potpourri of samples
The design freedom of the CRH system is illustrated on the following pages. Architectural styles using arches, protruding elements such as moldings, brick walls, half timbered, gable roofs, mansard style, frieze, architrave, or other decorative elements --you name them. All can be incorporated at reasonable cost simultaneously with the pouring of concrete because decorative elements are in the formwork preparation.

A two story dwelling of a modified Moroccan style. The protruding decorative elements are produced thanks to special accessories added to the forms. This house was built in Cancun where hurricanes are frequent and strong . The house shown at the right was built in the City of Mexico, where earthquakes are the main concern. There were 100 units built with 2 sets of forms. At left a detail of the balcony. The project included two other architectural styles for a total of 300 units as shown on the next page.

In the same development of the house on the previous page, another 100 units built using 2 sets of forms at a pace of 2 daily. In Mexico the French style is highly appreciated. Eugenio Aburto was able to provide it, even though these houses were meant for an affordable market. By using the accessories in the forms the moldings, the shutters, and the mansard roofing were all created at the time of pouring. This gave the homes the desired character and made them a good buy. Below is a detail of the balcony; the spindles are precast elements using a light weight concrete. .

This is a romantic Spanish style, reminiscent of the balcony on the first floor where the Spanish used to flirt with the young lady living in the house. The sales of this style were terrific.

The poured-in-place concrete system developed by me has no limitations. Here a multistory building is shown: the Hotel Komvaser built in Cancun. The space under the left wing of rooms is a big cistern to serve the water needs for operation uninterrupted at any time. Hurricanes sometimes shut down the Cancun water lines, but with the cistern there was no water shortage. The picture at right shows a vaulted roof built with a combination of steel trusses and colored waterproof plaster. Note the use of arches and columns capitals, all done by the special forming design.

As previously stated, the use of specially designed forms is the way of obtaining complicated architectural elements with poured concrete. One of the many properties of concrete is taking the shape of the mold. For repetitive shapes, the way to build at low cost is by inserting liners or decorative elements in the forms. The vaulted cantilevered roof shown in the picture below was built using one fiberglass form for all the roof. An embossed pattern made the underside of the vault look like the traditional Spanish terracotta blocks called “ladrillos.” A final coat of color made the appearance real. The cost was minimal. The picture at left shows the character achieved by the use of special forming in the concrete work. FINISHED VAULTED ROOF IN RED: THE FIBER GLASS ROOF FORM

MASTER PLANS An important document to show the placement of the structures to be build with the CRH system is the Site Plan. My concern as an architect is to create an environment where the residents have access to commercial and professional facilities, entertainment and good restaurants. Land uses should be close enough to allow walking or bicycling. Analysis of the site and contour lines includes slope degree, orientation, natural drainage, and existing vegetation. This is the basis for locating structures and services such as waste management, water recycling and trash disposal. The goal is to keep the habitat natural and place the buildings to facilitate energy conservation for low maintenance and durability.

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RAMMED EARTH HOUSES HOW THE CONCRETE RIB HOUSE WAS BORN In Calpulalpan, Tlaxcala Mexican Republic For Banco de Credito Ejidal Under Management of Professor Francisco Hernandez y Hernandez

Professor Francisco Hernandez y Hernandez, General Manager of the Banco de Credito Ejidal, give me a commission: build houses for the poorest people in Mexico, the farmers. It was a big challenge, with no budget for labor and little money for construction materials. I took the challenge and found the solution.
For labor, I used the future owners.
For construction material, I used dirt.
THE CONSTRUCTION SITE AND CONSTRUCTION MATERIAL SOURCE

I made an agreement with the farmers who wanted to have a house: they needed to provide the labor from beginning to end of the houses. Nobody would know which house will belong to which family. At the end of construction a drawing would be used to assign each house to a family. Everybody in the family was involved in construction. Women were in charge of bringing the food at the site and cheerleading the men. GRADING, SEWER LINES, ROUGH PLUMBING, TO START. STOCK PILING DIRT TO USE LATER

After concrete foundation and slab, rocks were embedded in the concrete to serve as hold downs for the walls. The Farmers Bank (Banco Ejidal) sponsoring the project was paying for the cement, but sand, gravel, and rocks were collected by the farmers. They were lucky because a little creek with abundant rock was close. ROCK DOWELS DETAIL In the photo at right a stock of dirt is visible in the foreground. Behind the farmers a wall can be seen. A Bank truck is delivering cement. Farmers build a shade structure at the right to have “tacos” with the family. Even the children come to discuss the construction advance and dream of having their own bedroom and a bathroom with out going outside. It was very rewarding doing this project.

Panoramic view of metal forms strong enough to accept the impact of the compactor when earth is rammed. Behind the form are walls from which the forms were removed. A village cornfield is growing in the rear.

This is a detail showing at the rear some forms in place, and a portion of wall where is an opening for a window. Note the lower part of the wall which has masonry concrete to prevent damage from rain. While observing this process I started to think about using concrete poured in forms in a similar way. Thus, 40 years ago the ides for the Concrete Rib House began. This system of rammed earth construction give dwellings to 30 families in the rural area of Calpulalpan, a village in the State of Tlaxcala, Mexico. As a result of their experience in teamwork, after moving into the houses, the farmers pooled resources and bought agricultural machinery and quickly became prosperous.

ONE OF THE FINISHED HOUSES HAS THE OWNER ENJOYING LIFE. THE FINISHING WAS USING AN EMULSION OF WATER AND LIME SPRAYED AGAINST THE WALLS, VYNIL PAINT AS ACCENT (THE BANK PROVIDED FOR THE PAINT)

ANOTHER HOUSE, DIFFERENT FLOOR PLAN

The walls have 2 coats of lime as finish, the color accents done with vinyl paint. ONE BEDROOM OF THE THREE

Dining area with furniture designed by me and built by the farmers. The finish: crude oil dissolved in gasoline. Joists concrete and metal U shape exterior reinforcement roof expanded metal lath with cement plaster (see next pg)

I designed innovative joists built with the steel reinforcement in the exterior, like crabs. U-shaped bent steel has connectors welded in the interior bottom. I also used this design for a prefabricated school in Cuernavaca for the Committee to Build Schools. When filled with concrete it works as a beam; the tension stress is resisted by the exposed steel. It avoids the destruction of trees for lumber, and makes the house fire resistant, at a low cost. Some of the 30 houses built with Rammed Earth, shown during construction

After building all the houses with rammed earth, I could not stop thinking about taking a shot at building the walls with poured concrete. The results are shown at left, just after taking the metal forms off the walls. Note the header with exterior metal reinforcement, similar to the joists described on the previous page. The picture below shows the structure of a house built in the 1960s with poured-in-place concrete. A similar system was used by the Romans around 2,000 years ago. It is interesting to note that the Anasazi, builders of Chaco Canyon, New Mexico, used a similar system with stone walls as forming and mud as bonding for a sort of masonry. Their structures, built around 700 ago, stand to awe tourists today. Concrete walls experiment

CIUDAD AZTECA 7,500 houses built In 15 months 8 schools, shopping center, offices Ciudad Azteca was a development managed by an aggressive young business man: Mr. Norberto Kanner, who create a real city for workers. I had the opportunity of building with my system of poured-in-place concrete. My effective building system contributed to the success of Mr Kanner’s Norka development project.

This experience was managing the construction of 7,500 houses using my poured-in-place masonry system. The houses needed to be affordable, and the system accomplished this because I used the abundant local stone for 30% of the volume of the concrete walls. This resulted in huge savings on materials cost. The system is very effective if modified according to the conditions of materials and labor availability. In this job wood forms were used; 25 sets of forms delivered 25 houses every day to buyers. It was gratifying to me to see the expression of happiness on the faces of the buyers moving into their new homes, with the children choosing their bedrooms and placing their toys with care. Above, the photo shows the foundation process, with a finished house in the background. The photo at right shows several houses in process, some ready for the roof, other for the finishing touches. Ciudad Azteca mass produced housing for workers

The picture at left has in the foreground a couple of workers placing a precast header at top of a window, details prior to the concrete being poured. The construction system used in Mexico makes a reduction of labor when placing windows and doors, headers and sills in the forming. The foreground also shows the wood forms in place, and a board with rocks which will be incorporated into the concrete to build the walls. Behind are walls built the day before – the forms from these walls were moved to the next lot (foreground). Note the window, header and sill standing in the wall, the sill is precast with decorative tile. In the opposite side of the street is a row of houses with the roof in place and being finished inside. The process for one story houses was: Foundation first day Walls second day Roof slab third day Four and fifth days finishing and delivering. Every day 25 foundations were built and 25 walls, 25 roofs, 25 painting and placing bathroom and kitchen fixtures. The fifth day 25 units cleaning and electrical wiring and plates in place, ready for the owner to take possession.

The construction of the roof slab used T-beams. This was similar to the CRH roof described on pages 15 through 18, but at the time these houses were built Styrofoam was not available for construction in Mexico. I used 6-inch CMU, as shown in the picture at right. Note the electrical conduit precut and ready to be wired on top. The steel reinforcement was prefabricated using welded wire mesh cut to fit and pre-bent as specified per structural calculations. The concrete poured was the fast-setting type to enable us to quickly remove the forms, take them to the next site, and let the painters and finishers complete the house. Each house was finished on the fourth day after foundation pouring. The workers were trained according to operation: foundation, walls, roof slab, and finishing. The finishing workers were female, because women showed special ability in this detailed work; they gave the job an interesting character, color and beauty. In addition, several marriages were arranged. I trained the plumbers and electricians doing the pre assembled elements. Their shop moved along with the advancing of the construction. Trained crews improved their skill with experience. They were paid by the piece, so they were motivated to work speedily. With practice they were able to double their output and also their wages. It kept the cost low, and made the workers happy. 1 5 4 2 3 1 – ROOF SLAB READY TO BE POURED. 2 – SLAB BEING POURED . 3 - SLAB FINISHED. 4 – JOIST REINFORCEMENT AND TOP OF WALL. 5 – NOTE CMU USED FORT-BEAM FORMING

I used all these former experiences when building the Concrete Rib House in the United States. The experience of building houses in the vicinity of Mexico City was beneficial because the area is often hit by earthquakes. No damages have been reported ever. GETTING READY TO ROOF POURING ROOF POURING 12 MEN CREW

The photographs selected show some of the affordable homes built in Ciudad Azteca, a community close to Mexico City. The development has so many families that it the Metro has been extended there, providing fast and economical transportation.

Photos 1, and 2 show two-story houses built in Ciudad Azteca. Photo number 3 shows a row of houses nearly ready to be occupied. 1 3 2

The size of the development required schools. Using the same construction system, I built eight schools, as well as the sales office shown at right.

COSTA BANDERAS A study of Investment and Returns for a Planned Retirement Development
The detailed study is divided in the following phases:
Project Revenues.
Project Expenses
Preliminary Investment
Land Ownership
Investments/Revenues Projections
The project has been designed to create a gate guarded residential community where residents will have access to shopping, theater, medical professional offices, an 18-hole golf club, tennis, and recreational facilities with natural and man-made greenbelts.
The master plan provides for 44 single family lots, 273, townhouses and 2640 multifamily condominiums.
An initial Investment of $ 10,000,000.00 with planned coordinated expenses of: engineering surveying, architecture and landscape planning, site preparation, infrastructure, roads, sewer treatment plant, building construction using the CRH system, advertising, marketing and sales will result in a net profit of $ 65,670,000.00.
Detailed spread sheets can be downloaded upon request to [email_address]
The project was designed for a property on the coast of State of Nayarit, Mexico.
The following pages will show preliminary sketches of the proposed buildings.

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About the author Eugenio Aburto, AIAE I am an architect, and a member of the American Institute of Architects. I started my building career taking civil engineering studies in the UNAM (National Autonomous University of Mexico). For several years I attended the engineering school while working as a general contractor. In partnership with concrete professor Mr. Marco Aurelio Torres H, a well recognized civil engineer, I had extensive engineering practice. My wishes were to design affordable dwellings but I decided I lacked design knowledge so I enrolled in the Escuela Nacional de Arquitectura ( architectural school) of the UNAM. When I applied to become a student again, the school administration noted my engineering experience; on the spot I was admitted as a student and offered the position of professor for Construction Systems. It was a lucky day because this helped me to pay for my studies. While teaching and studying I continued my construction activities. I designed and built several custom residences for wealthy people as well as factories and office buildings. But, I wanted to build affordable housing for the masses. With my own resources I developed a prefab system which caught the attention of an important industrialist, Mr. Leopoldo Peralta. He invited me to become a partner to start a company to build prefabricated metal houses. We named it CAPREFASA . But life was challenging me. Banks were reluctant to give loans to prefabricated houses; they said as soon as you put them in the ground the people will move them to another location. We built houses as long Mr. Peralta had money for the loans, but only a couple of hundred were built. By then I had finished my architectural studies and obtained the Architect diploma .

With recharged energy, and new ideas I needed to keep going. I formed my own prefabrication company improving the system. COMOSESA – Modular Sectionals Construction – was the name. I had several clients paying cash but a lot needed financing. I kept working until I ran out of money. A group of investors had connections in Guatemala and ideas for a big housing development for workers. It was my dream becoming reality! I accepted the commission of planning and designing, moved to Guatemala and started studying working conditions and materials availability. Guatemala City has a volcanic gravel of light weight, I started thinking about light weight concrete poured in place. I traveled to the USA to look for metal forms, and worked out master plans, houses and condominiums. Everything was fine until the source of financing stopped; the project never flew. But in Guatemala I had the time to accumulate a wide experience about construction methods. When I came back to Mexico, I was lucky because I found a position as consultant for the Committee to build schools in the Mexican republic, with good pay and opportunities for professional practice in the prefabrication field. One of my chores was to design a set of elements that could be transported to rural locations were the transportation was very restrictive. To meet this challenge I designed a metal bent structure with a maximum length of 8 feet. This enabled structural elements to be transported by donkeys. The parts had clips to be assembled by hammering. To handle longer spans, I designed beams which used the exterior metal envelope to get the tension stress when filled with concrete. An innovative school was built, and generated great attention. Eugenio Aburto showing his prefabricated school to the Mexican president Don Adolfo Ruiz Cortines.

This design was well appreciated but not supported by the building contractors. Their contracts call for pay according to the weigh od materials. The light weight structure meant they needed to work 10 times more for the same profit. While I was working in CAFCE, the manager of Banco Ejidal: Professor Francisco Hernadez y Hernandez hired me for moonlighting to build some rammed earth houses. I adapted a traditional indigenous packed earth construction system by using metal formwork and motorized compactors. During this process I had the opportunity of testing the idea of poured-in- place masonry concrete. Here I used metal forms which were very expensive. With my own investment I also built a couple of houses to test plywood formwork, but I was ready to look further. Good luck appeared again, when Mr. Norberto Kanner, a well seasoned developer, invited me to participate in a sort of contest. Several builders produced model homes in his development named Ciudad Azteca. Buyers were asked to review the models and choose the best. Buyers liked my one model better than those of the other builders who all showed at least 3 models. Because my model was the most popular Mr. Kanner hired me to build thousands of houses, eight schools, and a shopping center for his company, Constructora Norka. Another challenge appeared on my horizon, a new town, with houses for workers of PIPSA. These needed to be built fast on a piece of land with only hundreds of prairie dogs. I did a fast master plan and hired a company to do the infrastructure. While the contractor worked on the infrastructure, I with my team of workers started building. We completed the project on time and the development was inaugurated by the new president, with big media coverage. But when the man who hired me for the job wasn’t chosen for the political position he was hoping to get I left my government position and returned to the private sector. Eugenio Aburto and the great ex-president Don Lazaro Cardenas inspecting the rammed earth houses built by EA in Calpulalpan, Tlaxcala. Mexican president Don Luis Echeverria Alvarez in the inauguration of PIPSA houses built by Eugenio Aburto, who is talking about his concrete system.

Back working by the private sector I built several affordable houses, one model in modern style, another French, and the third Spanish. The houses for Gonzalez Reyes Developer sold like hotcakes. Next I built several houses in Acapulco, for Carlos Fernandez who owned a lime factory. Then I had a contract to do the landscape and the bicycle trail in the newly developing resort of Cancun. To keep me busy in the housing field I built 10 concrete houses in Cancun with my own investment. When the bike trail contract was finished I had a piece of land with my offices and sleeping quarters for my workers. In that time Cancun was jungle, and to have labor it was necessary to provide lodging. I decided to test the concrete system in a building of several stories, and the Hotel Komvaser was built. Building a modular structure like a hotel is especially cost effective with my system; with a set of formwork I was building a room per day. I soon tired of being a hotel manager, and I missed my profession. I moved to the USA, obtained the architect license in California, and worked in several architectural firms. I enjoyed exploring new customs, styles and construction practices. Finally in 2007 I built the Concrete Rib House , in the USA , to show a sample of how to produce a building structure resistant to natural calamities with affordable cost. And this is were I am now.

Special thanks to the many consultants and suppliers who were very supportive and informative throughout this project. Their efforts greatly contributed to the success of the first Concrete Rib House. Structural Calculations Julio M. Guerra , Structural Engineer Survey and Grading Plan JHA Engineering, Inc. Energy Calculations Joan Hacker Grading Steve Peulicke , Desert Excavation Construction Consultant Oscar Tovar Marketing Consultant Peter Andrada CONSTRUCTION Concrete Work: Carlos Boyzo and crew (pouring) Leonzo Fuerte (pump) Formwork Glenn Tovar and crew (forming) C&M Building Materials, Inc . reinforcing materials Ready Mix Concrete A1 Aggregates, Inc. and Superior Forming Hardware R andy Haas , White Cap Ron Melby , HUB Curb Sawing. Curb Sawing, Inc. Rigid Foam insulation Universal Packing, Inc. Stucco Felipe Martinez Plumbing ABC Plumbing, Inc. Electrical Samuel Flores Air Conditioning Comfort Air Doors and hardware Builders Supply Windows Coachella Valley Window & Doors Custom corner windows Midwest Glass Acrylic domes A.I.A. Industries Garage doors Paragon Schmid Drywall and texture La Roca, Juan Barrera Granite work Juan Avila Tile Eutilio Cambron Detailing Martin Alcantar Carpeting D&D Carpet Mill Outlet Thanks to the staff of the Cathedral City Building Department: Gil Estrada, Victor Ruiz, Diane Sawa and Wyvette Ganther

ADDENDA About Rigid Insulation. Expanded Polystyrene (EPS), is the generic industry name for a white rigid material made by expanding polystyrene beads with steam and bonding the beads together under pressure in a block or shape mold. EPS is used in the construction industry for insulation and void fill. It is also used in a variety of packaging applications including coolers, wine shippers, molded end caps and corners. It can be cut into an unlimited variety of shapes. EPS columns can be straight or tapered, smooth or fluted. Bases and capitals are available in an unlimited variety of sizes and configurations. The columns can be for aesthetics only can be delivered in two halves to be installed around a structural column. This is a sample of comments from contractors and material providers. And can be as detailed as each one decide.

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Concrete Rib House - Complete

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