Off-site and on -site modern method of construction

Off-site And On-site Modern Seminar Report 2016
Method Of Construction
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Dept. Of Civil Eng. CKC Mannoor
CHAPTER 1
INTRODUCTION
1.1 GENERAL
Many people prefer homes built the traditional way, board by board, nail by nail, right
close by at the construction site. Nevertheless, they don't construct them like they used to.
The huge mainstreams of houses these days are built with at least some factory-built
components. And a healthy proportion are put together almost totally off-site. The cause is
generally cost. The building method approach to home building save time, and time is
money, not just to the people who raise houses but as well to the people who pay money for
them . Modern Methods of Construction (MMC) originated in the United Kingdom (UK) as a
common term for offsite methods of construction and onsite methods of construction. Offsite
MMC are prefabrication elements or parts of structures, constructed in factory, then
transported and assembled on-site. Onsite MMC are building blocks and parts of structures
takes place directly on site. Virtually all of the good quality products are built in factories
around the world. Cars, planes, ships, computers, printers, cell phones, even the pen you
write with are built in factories. In addition, even site built homes use many components that
were produced in factories. Modular homes take a shorter time for construction compared
with site-built homes. This is due to the fact that while the modular is being built in the
factory, another crew is building the foundation at the same time.
The continued population growth affects the amount of construction. At the same time
the need for housing and services is also increasing. Therefore increases the need to find new
modern methods and materials for construction. Together with the needs of the population
their demands for the development of technical and technological requirements steadily
increases in all areas . This results in the increasing demands for quality housing, which in
turn also requires finding new ways and opportunities applicable in construction. One
possibility includes modern methods and materials of construction. Prefabricated production
construction represents mass production, which takes place in factories while greatly

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shortening the construction time and having positive impact on the environmental aspect.
Modern construction methods and materials have very broad application in the construction
industry. Their biggest advantage is ability to be implemented on site and also in the
manufacture off-site, allowing shortening the time and increasing precision of construction.

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CHAPTER 2
MODERN METHOD OF CONSTRUCTION (MMC)
2.1 DEFINITION
A construction process that can encompass the use of composite new and traditional
materials and components often with extensively factory produced sub-assembly sections and
components. This may be in combination with accelerated on-site assembly methods and
often to the exclusion of many of the construction industry traditional trades. The process
includes new building and retrofitting, repair and extension of existing buildings.
2.2 BENEFITS OF MMC
 Improved quality control of components produced under factory controlled
conditions.
 Services (eg. electrics, plumbing) can be pre-planned and either fully or partly pre-
installed for final connection on site.
 Faster construction times on site.
 Fewer workers required on site and for shorter periods.
 Less wastage of materials.
 Lower overall construction cost.
 Enhanced durability.
 Better architectural appearance.
 Enhanced occupational health and safety.
 Material conservation.
 Less environmental emissions.
 Reduction of energy and water consumption.
Today, modular constructions are more than just temporary construction trailers and
portable classrooms. There are countless applications for modular building solutions – from

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permanent housing in both remote and urban locations to retail space solutions and municipal
facilities, to industrial site offices and special event requirements.
Hundreds of end users benefit from the ease of use and flexibility that modular
construction offers. Attractive prefabricated buildings can be any size, have multiple stories
and custom designed to meet specific needs.
Modular constructions are manufactured in a dry, secure facility, where predictability of
quality centered in a factory benefits the project. Modules are easily transported to site for
installation. This process saves project time and money because site preparation occurs while
the buildings are being manufactured and there are no weather delays. Site installation is also
much faster than ‗stick-built‘.
The key advantage of modular construction is that it's more cost effective than
traditional on-site building. Modular builders take advantage of economies of scale by
building multiple similar pieces at once. They also get to work on smaller pieces of the
building, reducing the need to use ladders or scaffolding. Finally, since the bulk of the
construction and finishing
work is done indoors, there's less risk of weather-related delays in construction that can cause
workers to sit around idly waiting for the ability to work.
The nature of factory building also makes modular homes faster to build. They're
frequently built on an assembly line that continuously operate. Companies have their own
inspectors on site, so the units can be checked as they're built without having to wait for a city
inspector to come and sign off on the work. Finally, when they get built on-site, all that needs
to be done is to have them placed on the site and joined together. This process can be
completed in hours or days instead of weeks or months.
A modular home is a new home. This means that it's built to modern standards and
comes with new appliances and systems. Since it's a newly built home, you also get to select
your lot and, based on your community's laws and your builder's advice, site the house where
you want it on your parcel. On the other hand, building a new home means that you need to
find a lot and prepare it for building if it isn't already developed. You also can't move in when
you close since you have to wait for the construction to finish.

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2.3 CLASSIFICATION OF MMC
The classification of MMC are listed in the table 2.1.
Table 2.1 Classification of MMC
Off-site
MMC
Systems Components
Volumetric Construction
Modular Construction
Pod Construction
Hybrid Construction Semi-volumetric construction
Panellised Construction
Open Panels
Closed Panels
Structural Insulated Panels - SIPS
Composite Non – structural Insulated
Panels
Prefabricated Parts
Prefabricated Lightweight and Roof
Panels
Natural materials
Timber Frame Construction
Multi- layered Engineered Timber (Solid)
Components from Renewable Materials
Light weight facades
Masonry block walls with timber frame
Masonry block walls with metal frame
The Ventilated Facade system
Pre-cast concrete foundation assemblies

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Sub-Assemblies and Accessories
Systems
Floor or Roof Cassettes
Pre-cast concrete foundation assemblies
Pre-assembled products
On-site
MMC
Prefabricated auxiliary
structures (site
assembled)
Tunell Form
Stick Build Timber Frame
Insulated Concrete Formwork (IFC)
Thin Joint Blockwork / Clay Block
Oak Framed Buildings
Glulaminated Framed Building
2.4 PROPERTIES AND CHARACTERISTICS OF MMC
 Mass production
Investment in equipment and human resources associated with industrialization can only be
justified in cases where the recorded volume production. Distribution of this size allows fixed
costs for large quantities, without unduly increasing the final cost.
 Flow production
Production of large amounts of standardized prefabricated elements allows a high level of
production process. This process can be divided into a larger number of larger tasks. In such
system work, workers perform repetitive activities while increasing their productivity.
 Production Equipment
Capital employed for the initial investment is a very important factor. Plant, equipment and
skilled workers must be obtained before they start production. Such huge investments may be
used only if there is sufficient demand for the product. On the other hand, the production of

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the product may be carried out directly on the construction site, thus minimizing
transportation costs.
 Equipment site
Construction and installation of prefabricated panels and their location on their position
requires different equipment. In the case of construction of such a system it is important to
incorporate sufficient operating costs. A typical device is a crane that is used in the
construction of multi-storey buildings.
 Construction time
The use of different systems of modern methods of construction can significantly shorten the
construction period. In a large extent this is influenced by the fact that these methods require
less amount of work on the construction site. This is illustrated in Figure 2.1.
Figure 2.1 Degree of labour and construction time by using MMC
 Modular coordination
Modular coordination is a unified management system for sizing space and components so
that all elements fit into one another without any modifications, such as the trimming or
lengthening, even if they are supplied by different manufacturers.
 Integration
Optimum results require a high degree of cooperation between the different parties, which are
the designer, manufacturer, customer and supplier. This can only be achieved through an
integrated system.

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 Transport
Panels can reduce production costs by up to 30%. However, this saving is partially offset by
shipping costs. Transport of large panels is also subject to certain restrictions.
2.4 BARRIERS OF MMC
 Political Context
Sustainability of construction is one of the main reasons to use modern progressive methods
and materials of construction. Currently, the pressure on the sustainability of construction is
increasing. There are several perspectives on sustainable construction. One is the economic
view. Important is the social aspect and the environmental aspect also. It also has an impact
on creating the environment in the form of legislation. Process automation, emphasis on
environmentally friendly materials and technologies in the construction process is large.
 Construction skills
MMCs require highly skilled labour, both for producing parts and modules for MMCs in
factories and for the precise on-site assembly of these parts. Progressive materials are in
many cases difficult to integrate into the construction process because of the lack of
knowledge about them. Construction companies should seek training programs for
employees. Emphasis is on knowledge about new materials and work with them.
 Quality of construction
Quality construction and final construction work has a significant impact on the decision on
the selection of materials and methods of construction. Perceived quality construction also
plays a big role. Progressive materials should not only be flexible in terms of time and cost of
construction sites, but also quality.
 Costs of construction
Perception of costs is very sensitive. Economic assessment of projects is often the basis for
decision making. In general, it is the pressure to develop economically available materials.
Modern methods often offer more efficient use of materials. When using modern methods of
construction, costs are minimised,which has a positive effect on their use.

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 Pace of construction and construction time
For decision making, the choice of materials and methods used in construction is also
important for planning the duration of construction time. The use of MMC has positive
impact on the construction period. This is one of the biggest advantages of using these
methods.

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CHAPTER 3
OFF-SITE CONSTRUCTION
3.1 INTRODUCTION
Off-site is a term used to describe spectrum of applications where buildings,
structures or parts are manufactured and assembled remote from building site prior to
installation in their final position, in other words, moving operations that are traditionally
completed onsite to a manufacturing environment or A construction process that can
encompass the use of composite new and traditional materials and components often with
extensive factory produced sub-assembly sections and components. This may be in
combination with accelerated on-site assembly methods and often to the exclusion of many of
the construction industry traditional trades. The process includes new buildings and
retrofitting, repair and extension of existing buildings. Off-site construction is also known as
prefabrication, modular construction, off-site manufacturing/assembly/production/fabrication,
system building, and industrialized construction .Off-site construction (OSC) is one of those
innovative processes where adoption is very limited within the industry.
The purpose of modern methods of construction including prefabrication, off-site
construction, or manufacturing is to move some of the activities from on-site construction to
offsite into a controlled manufacturing environment. Off-site manufacturing (OSM) is a
construction technique in which prefabricated and standardised components/modules are
manufactured in a controlled factory environment (either on- or off-site), transported, erected,
and assembled into the on-site structure. OSM requires rethinking about the entire project
development process, in order to take full advantage of both on- and off-site activities.
Construction industry players in many countries started to think about innovative ways of
construction by integrating the off-site production with the on-site activities.
OSC has been seen to reduce construction time; simplify construction processes;
provide higher quality, better control, and more consistency; produce products that are
factory tried and tested; reduce costs when resources are scarce or in remote areas; result in

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improved working conditions and reduced on-site risks; alleviate skills shortages in certain
areas; revitalize traditional manufacturing regions; provide fewer trades and interfaces to
manage and coordinate on site; facilitate the incorporation of sustainable solutions; and
achieve better energy performance. Adoption of OSC introduced new construction problems
in terms of design, transportation, supply chain, and installation processes.
3.2 BENEFITS
 Time Saving
The most significant benefit of off-site construction is the time savings that it brings about.
By transferring a significant proportion of the construction work to an off-site facility, the
time spent on-site is reduced. The more predictable conditions of the factory and the
economies of scale that they generate can also ensure that construction deadlines are met
more effectively than in a traditional on-site environment. Over 40 per cent of all responses
chose time/speed as the main reason for choosing off-site construction. Pre-assembly enabled
less time to be spent on site and a reduction in commercial risk as a result of faster time
frames for projects. Time to be the greatest advantage of off-site construction methods.
Among contractors, the most frequent reported benefit of off-site construction was the
reduction in overall project schedule and the reduction in construction duration, both of
which are related to time.
 Quality Improvement
Another significant benefit was quality improvement. The main advantage of off-site
construction in this regard is that it enables a tighter control over quality than an on-site
environment. The elements made off-site, in a factory, were more consistent and had gone
through a greater degree of quality control and testing than elements made onsite. Less time
spent on snagging (remedial works) was also mentioned as a benefit.
 Addresses Skills Shortages
A third major factor of off-site construction was that it relieves skills shortages in the
construction industry. Off-site construction essentially enables the construction process to be
‗outsourced‘ to another environment, requiring less labour to be invested into traditional on-
site processes and addressing the shortage in this area.

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 Cost Reduction
The fourth perceived benefit of off-site construction is cost saving. It was cited to be a major
advantage as quite high in its initial cost. The improved cost certainty of off-site construction
was a major driver for its use by house building companies. This may be explained by the
fact that off-site construction is more predictable and less likely to suffer from cost blowouts
caused by unknown factors such as the weather. The other benefits of off-site construction,
such as better quality and reduced remedial work, are often not included in costings. The cost
of maintaining off-site bathroom modules can often be as low as one-third those of bathrooms
constructed on site. while initial costs may appear higher, the actual cost of off-site
construction methods (particularly over the whole life of the project) may be cheaper than the
use of traditional on-site methods.
 Productivity Improvement
The concept of productivity provides another way of conceptualising the benefits of off-site
productions.
3.3 FORMS OF OFF-SITE CONSTRUCTION
3.3.1. Volumetric Construction
Factory produced three-dimensional units that are then transported to site and bolted
together. The frames will normally be steel, timber or concrete and can be supplied with all
external and internal finishes (including services such as electrics and plumbing), or solely
the basic structure. Unlike pod construction, volumetric does not require a superstructure.
Examples include: hotels, student accommodation, fast food restaurants.
Volumetric construction (also known as modular construction) involves the ‗off-site‘
production of three-dimensional units. Quality controlled systems of production in the factory
should be in place and expected as part of any third party approval. Modules may be brought
to site in a variety of different forms, ranging from a basic structural shell to one where all the
internal and external finishes and services are already installed.
Volumetric construction can consist of timber frame, light gauge steel as well as
concrete or composite constructions. The units are sometimes used alongside panels (ready
made walls, floors and roofs) in hybrid construction. External cladding may form part of the

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prefabricated system with only localised on-site specialist sealing required. Alternatively,
traditional masonry cladding may need to be constructed, in which case specific detailing for
support of claddings, cavity barriers and damp proof courses must be pre-agreed and checked
by Site Managers. Volumetric construction is most efficient when used for large numbers of
identical units, as may be found in flats. A house is typically made up of four units plus roof
(which can be either pre-fabricated or conventional). A flat usually comprises one, or more
commonly two units.
Volumetric construction have two components they are:
i. Modular Construction
ii. Pod Construction
Modular Construction
Modular construction is a term used to describe the use of factory-produced pre-
engineered building units that are delivered to site and assembled as large volumetric
components or as substantial elements of a building.
Figure 3.1 Factory producing volumetric units

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Figure 3.2 Placing of Volumetric units
Figure 3.3 Completed block of flats in volumetric construction
Pod Construction
Pods were introduced into the construction market for hotels and student accommodation,
although their use in apartments and housing is increasing. Pods are usually non-structural
and are normally used within a loadbearing structure. The enclosure can be of steel frame,
timber frame, concrete or composite constructions Factory produced three-dimensional
elements that are incorporated into the superstructure of a building. These are ready made
rooms which can be pieced together to make complete premises when set within a light steel
framework. All the building services will typically be pre-installed with just the final

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connection made on site. Examples include: hotel bathrooms, kitchen units for
accommodation blocks
Figure 3.4 Stages in the construction of bathroom pods
3.3.2 Hybrid Construction
These structures combine both volumetric and panellised approaches within the same
building and are also known as semi-volumetric. Hybrid systems, otherwise known as pods,
consist of fully manufactured or prefabricated building facilities, which are factory built and
with all finishes complete. In hybrid systems, all furnishings and finishes are completed and
transported from the factory to be placed on site. Highly serviced areas such as kitchens or
bathrooms can be constructed as volumetric units, with the rest of the dwelling constructed
with panels.
Figure 3.5 Hybrid Construction

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3.3.3 Panellised Construction
Flat panel units built in a factory and transported to site for assembly into a three-
dimensional structure or to fit within an existing structure Systems can include wall, floor and
roof panels to create the complete structural shell. Factory-made structural floor and roof
panels are known as ‗cassettes‘ They can be load-bearing (ie. Providing structural support) or
non-load-bearing. They can be made of timber, light gauge steel, structurally insulated panels
(SIPs), concrete or non-structural in-fill walling used to create the whole building. They can
be used for virtually any type of building. Examples of components generally constructed
using the panelised system include doors, windows, cladding, timber frames, and insulation.
There are many different types of panel, the main types are:
i. Open Panels
Panels delivered to site where insulation, windows, services and linings are fitted. All
structural components are visible. Panels can be structural (transmitting load to the
foundations) or non-structural (used as non-loadbearing separating walls and partitions).
Typically delivered to the site purely as a structural element with services, insulation,
cladding and internal finishes installed in situ
Figure 3.6 Open Panel Timber Frame

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ii. Closed panels
Panels based on a structural framing system (such as the type used for open panel systems),
which can have factory fitted windows, doors, services, internal wall finishes and external
cladding. The internal structural components can only be seen around the perimeter of the
panel. Typically include more factory-based fabrication such as lining materials and
insulation and may even include cladding, internal finishes, services, doors, and windows.
Figure 3.7 Closed Panel Timber Frame
iii. Concrete panels
structural wall panels, which can include cladding (often bricks or brick slips), insulation
materials, windows and doors.
Figure 3.8 Concrete Panels

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Figure 3.9 Concrete panels complete with insulation and half brick cladding
iv. Composite panels
Panels made from a combination of different materials that act together to provide
structural support. Structural insulated panels are a specific form of composite panel.
Figure 3.10 Composite Panel
v. Structural insulated panels (SIPS)
Sandwich construction comprising two layers of sheet material bonded to a foam insulation
core. They do not rely on internal studs for their structural performance. Used primarily as
wall and roof panels. Structurally Insulated Panels (SIP‘s)comprise a Structural Core of
Insulation which is glue bonded on each face to a racking board –Materials for the board

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varies with manufacturers but typically are Plywood, OSB or one of the new Composite
Boards.
Figure 3.11. Structural insulated panels (SIPS):
vi. Infill panels
Non-loadbearing panels inserted within a structural frame. Any type of panel can be used
although framed panels are more common. Masonry can also be used.
Figure 3.12.Infill Panel
vii. Curtain walling
Vertical building enclosure system that supports no loads other than its own weight and
the environmental loads that act upon it.

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Figure 3.13 Curtain Walling
3.3.4 Natural Materials
There are many different types of natural materials used for construction, the main types
are:
i. Timber Frame Construction
Traditional timber framing is the method of creating framed structures of
heavy timber jointed together with various joints, commonly and originally with lap jointing,
and then later pegged mortise and tenon joints. Diagonal bracing is used to prevent "racking",
or movement of structural vertical beams or posts.
Figure 3.14 Timber Frame Construction
ii. Multi-Layered Engineered Timber
Engineered wood, also called composite wood, man-made wood, or manufactured board,
includes a range of derivative wood products which are manufactured by binding or fixing

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the strands, particles, fibers, or veneers or boards of wood, together with adhesives, or other
methods of fixation to form composite materials.
Figure 3.15 Multi-Layer flooring wood
3.3.5 Light Weight Facades
A facade or façade is generally one side of the exterior of a building, especially the
front, but also sometimes the sides and rear.
There are many different types of light weight facades used for construction, the main types
are:
i. Masonry block walls with timber frame
In this masonry blocks are constructed in the platform of timber frame.
Figure 3.16 Masonry block wall with timber frame

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ii. Masonry block walls with metal frame
In this masonry blocks are constructed in the platform of metal /steel frame
Figure 3.17 Steel wall Frame
iii. The Ventilated Façade system
Ventilated type façade and wall coverings were developed to protect buildings against the
combined action of rain and wind by counterbalancing the effect of water beating on walls
and keeping the building dry, with high level aesthetic characteristics and undisputed
advantage of heat insulation and soundproofing.
Figure 3.18 Ventilated façade wall

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3.3.6 Sub- Assemblies and Accessories Systems
Sub-assembly is the process by which building components, materials, prefabricated
parts, and equipment are constructed together at an off-site location before being transported
to a site to be permanently erected. These parts are generally small components of a building
and typically include systems such as roof trusses, precast concrete beams, floors and
columns, piping, and staircases. Larger components that can be incorporated into either
conventionally built or MMC dwellings These items are not full housing ‗systems‘ and are
usually factory made or, occasionally, site-assembled.
Sub-assemblies and components in this category are:
i. Pre-fabricated foundations
A series of pre-fabricated ground beams and other components assembled to form
foundations quickly and accurately.
Figure 3.19 Prefabricated Foundation
ii. Floor cassettes
Pre-fabricated panels specifically designed for floor construction. Fewer labour hours on-site
are needed per square metre of floor, and reduced work at height has potential health and
safety benefits.

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Figure 3.20 Floor casettes
iii. Roof cassettes
Pre-fabricated panels designed specifically for pitched roofs. The panels are very stiff and are
designed to leave the loft free of struts and props, allowing easy production of ‗room in the
roof‘ construction. Using roof cassettes allows the building to become watertight more
quickly than with conventional trussed rafter or cut roof constructions.
Figure 3.21 Roof Cassettes
iv. Pre-assembled roof structure
Roofs assembled at ground level before constructing the shell of a dwelling. The roof can be
craned into place as soon as the rest of the superstructure is in place, creating a weather tight

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tructure more quickly than assembling the roof in situ. There are also health and safety
benefits resulting from the workforce not undertaking all the work at height.
Figure 3.22 Pre-assembled roof structure
v. Pre-fabricated dormers
Factory made dormers can speed up the process of making the roof watertight.
Figure 3.23 pre-fabricated domers

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vi. Pre-Fabricated Chimney Stacks
Factory made lightweight chimney stacks (often clad with brick slips) for mounting on a roof
structure without the need for a masonry flue, make them suitable for lightweight frame
constructions. The stacks can accommodate flue liners and so function with combustion
appliances.
Figure 3.24 Pre-fabricated chimney stacks
vii. Wiring looms
Cabling systems manufactured so that they can be assembled quickly with relatively
unskilled labour. Cables are manufactured in various lengths and terminated with plugs that
simply plug into sockets and other electrical items.

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Figure 3.25 Wiring looms
viii. Pre-fabricated plumbing
Pipework and fittings pre-assembled for use in volumetric units to facilitate the rapid
throughput of units in the factory.
Figure 3.26 Pre-fabricated plumbing
3.4 MANUFACTURING OF MODULES
The production of modules consists of a series of steps, each of which has specific tasks.
Each of the components is designed to optimised the manufacturing process and ensure waste
minimisation.

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3.4.1 Floors
Floors can be made of hot rolled steel sections welded together, or constituted of
galvanised cold formed joists and beams bolted together. In both cases, the cutting pattern of
the structural components from standard lengths is carefully planned to reduce, if not
eliminate, wasted materials. However, the steel off-cuts are collected in designated skips and
sent to the suppliers for recycling.
The floor decks are typically constituted of chipboard. Because the standard
construction size does not always suit the floor dimensions, there is a small amount of timber
based waste. In most cases, this timber based product is either burnt in a wood furnace or sent
to landfill. However, Yorkon has worked with its suppliers in order for the floor deck board
manufacturer to deliver panels that suit the dimensions of the floor frames. This had a direct
effect on the productivity of the floor line by reducing the amount of operations required, and
eliminating the production of timber based waste.
Figure 3.27 Manufacturing Of Floors
3.4.2 WALLS
The wall construction adopted by Yorkon is a composite panel consisting of one layer
of Fireline board and one layer of Plastisol-coated steel on either sides of a polyurethane
insulation layer. The boards are kept apart by timber studs and foam spacers. The panels are
designed to sustain the loads for transportation and lifting, as well as to limit the air
infiltration through the wall itself. The standard assembly details also provide instructions to
limit air infiltration through the interfaces with floors, ceiling and adjacent panels.

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The wall panels are manufactured to be of the length of the wall in order to avoid
redundancy in the structure, thus limiting the use of materials and resources. Furthermore,
Yorkon has recently introduced a lower density material for insulation (40 kg/m3
instead of
45kg/m3
). This change in insulation specification, whilst having limited impacts on the
thermal performance of the panels, has reduced the quantity of insulation materials used per
unit built.
Windows are installed in openings cut out of the wall panels. The offcuts are
recovered and stripped. The steel is stripped and sent for recycling, whilst the insulation is
reused for floor insulation of standardised Portakabin closed modules. Therefore, the
production and assembly of wall panels does not generate any waste that is sent to landfill.
Three years ago, Yorkon established that packaging constituted the largest area of
waste generation through the manufacturing operations. Since then, Yorkon has worked with
its supply chain to ensure that such waste would be eliminated. Windows, for examples, are
now delivered to the factory on steel stillages that are return to the window manufacturer for
reuse.
Packaging for ancillary items was also one of the biggest generator of cardboard
waste. Yorkon, in cooperation with their suppliers, have rationalised and standardised the
dimensions of the fixing, screws, bolts, etc to limit the number of different sundry items
integrated into the construction of the modules. The system currently in place allows the
suppliers to tour the factory with a small vehicle every two days and to replenish the sundry
racks (Kanban) at each work station with supplies that are about to run low. By applying this
method, Yorkon and its suppliers have eliminated all needs for packaging, reduce the time
lost by the labour for fetching supplies from the stock store, and efforts for keeping/managing
stocks in stores.

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Figure 3.28 Manufacturing Of Walls
3.4.3 CEILINGS AND ROOFS
Ceiling and roof elements are also assembled together prior to being fixed onto the
main structure of the module. As explained previously, the ceiling/roof is designed to be
weather tight to provide protection to the interior of the module during transportation and
installation on site.
Yorkon has adopted the same buyer-supplier approach to the design and procurement
of the components of the ceiling and roof panels. All structural elements are made of
galvanised pre-punched steel plates that are delivered on specially designed steel racks. These
racks are returned to the suppliers for reuse. The production process of the plates follows the
same requirements of optimisation of the use of materials than those described for the
construction of floors. Similar procedures are applied to recycling of the unavoidable steel
waste.
The roof steel panels covering the modules have been designed by the suppliers to suit
the standard roof dimensions of the modules. These are pre-cut and sent to the factory in
specially designed racks that are returned to the suppliers for reuse. Likewise, the flashing are
manufactured by the suppliers in single lengths and delivered to the factory on special racks
that are also returned for reuse.

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As for the wall panels and the floor construction, the ceilings and roofs production
generates a limited amount of
waste (sealant cartridges, plastic covering, etc.) that is segregated in specific skips and sent
for recycling.
Figure 3.29 Manufacturing Of Ceilings And Roofs
3.4.4 Mechanical And Electrical Equipment
Yorkon has worked with its supply chain in order to ensure that the amount of
packaging is reduced to a minimum. The utilisation of reuseable stillage and containers have
helped the operations to significantly reduced the amount of packaging cardboard and plastic
dealt with at the factory. Wherever there is unavoidable packaging, the subsequent plastic,
cardboard and polystyrene waste is sent for recycling.
Electrical waste is now negligible. Again, close cooperation between the manufacturer
and its suppliers has evolved enabling electrical wiring to be delivered ready for installation.
The marked cable and wiring are installed as indicated on the electrical drawings and does
not require cutting other than the preparation of the wire ends for connections. This procedure
eliminates waste such as copper wire and cables, timber and cardboard reels.

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Plumbing is now carried out with push and lock plastic systems. Currently the waste
generated by this activity is recycled.
3.4.5 FINISHES
In traditional construction, the fitout phase generates a significant amount of waste.
However in volumetric modules the waste generated by finishes is limited to packaging
(plastic and cardboard, plastic tins, sealant cartridges, etc). Moreover, due to the large volume
of materials used, the optimisation process and management put in place at Yorkon
eliminates waste due to spoilage, accidents, over-ordering, etc. Only this rationalisation of the
use of finish products based on the factory‘s overall needs, thus not project specific, can
achieve such a dramatic reduction of waste in comparison to the same activities on site.
Figure 3.30 Finishing Work
3.5 DELIVERY TO SITE
Once the modules are completed, they are loaded on lorries and transported to site. As
explained earlier, the roof/ceiling structure is designed and built so to provide weather
protection to the interior finishes. However, some of the modules may have open sides, or
interior wall finishes that need protection from weather and transport. Yorkon, like some of
its competitors, has developed a curtain system that protects the interior of the modules
during transportation. Once the modules are bolted together on site, these curtains or
transport sheets are brought back to the factory for reuse.

33
On site, the modules are lifted from the lorry and put into place using a crane. The
connection to the services and to adjacent modules and foundations are made within a few
hours. Some of the finish has to be completed on-site. This is normally carried out as the
erection process continues. All materials are supplied in measured quantities sufficient to
carry on the work required with any remaining materials returned to the factory.
Overall, the deliveries of modules to site and their installation on site do not produce
waste. Moreover, compared to traditionally managed sites, the number of deliveries is
considerably reduced, thus impacting positively on the CO2 emissions and the CO2 footprint
of the building.
Figure 3.31 Delivery To Site

34
CHAPTER 4
ON-SITE CONSTRUCTION
4.1 INTRODUCTION
Site based assembly methods include the use of traditional components but in
innovative designs including the establishment of manufacturing facilities at construction
sites. An example of this is air crete planks that have the strength of concrete but whose
micro-cellular structure is low in unit weight. Onsite Systems comprise many methods which
benefit from the use of modern materials. As the name implies, these systems are mainly
assembled or constructed ―Onsite‖ –The methods are many and varied, the ―Systems
Approach‖ leads to increased speed & quality. Innovative methods of construction used on-
site and the use of conventional components in an innovative way.
4.2 VARIETY OF SYSTEMS IN ON-SITE CONSTRUCTION
4.2.1 Tunnel Form
Concrete bays cast between ‗L‘-shaped steel shutters .The ends of the bays are in
filled with other materials (eg masonry, light gauge steel or timber frame panels) to create a
habitable space.
Figure 4.1 Tunnel Form

35
4.2.2 Insulating formwork
Insulation in the form of hollow blocks or sheets used as permanent shuttering for
concrete to create the external walls of a dwelling. Very airtight and thermally efficient
dwellings are created using this system. Essentially a Manufactured Prefabricated Insulated
Shutter which is built from individual ―Blocks‟ which are then reinforced & the voids are
then Concrete Filled
Figure 4.2 Insulating Concrete Formwork(ICF)
4.23 Aircrete
Aerated concrete products (thin joint block work or aircrete planks) used to form the
major elements (ie walls, roof and floors) of a structure.
Figure 4.3 Aircrete sustainable building block

36
4.2.4 Stick Build Timber Frame
Stick building is simply the construction of a timber frame on site utilising loose
timber. It is a flexible system that avoids the need to pre-fabricate panels in a factory and is
therefore cheaper, easier and quicker to procure.
Figure 4.4 Stick Build Timber Frame
4.2.5 Thin Joint Systm
Thin-Joint construction combines the use of large format, accurately dimensioned
aircrete blocks and quick setting mortar to create a highly productive and cost-effective
building system. The system promotes the use of much larger blocks with 2mm joints, rather
than the traditional 10mm joints and can be used for solid or cavity walls in all types of
buildings, be it houses, apartments, commercial buildings, schools or offices. Manufactured
to high tolerances which enables very thin joints between blocks to be made -Increasing the
thermal performance by reducing the joint thickness & improving Air Tightness, other
benefits include increased speed on site and wastage reduction.
Figure 4.5 Thin Joint Block Work

37
4.2.6 Oak & Glulam Framed Buildings
Post & Beam type systems can still be classified as MMC as often the framework is
used as the Primary Structure & Insulated Panels are used to provide the walling elements
Figure 4.6 Oak & Glulam Framed

38
CHAPTER 5
CONCLUSION
Modern methods of constructions are not new in developed countries in Europe and
the USA. Modern methods of constructions should be seen as innovation in construction. It is
imperative that modern methods of constructions are seen as an evolution of construction
using new and innovative techniques rather than a revolution. The use of MMC has
indisputable advantages. Several studies declare an economic advantage and shorten the
construction period. Similarly, the use of progressive materials has a positive impact on the
sustainability of construction. Defining of these benefits is very important for several reasons.
One of them is the interconnectedness of the key factors in the use of MMC and advanced
materials in the construction with their advantages.
Modern methods of constructions are not to be seen as a threat to traditional methods.
Both methods should be able to work together and improve their processes collectively.
Common ground benefits of modular construction philosophy begin to break the
unprofessional especially from the public. Examples from abroad clearly demonstrate that
this technology has potential even in modern architecture. The use of new materials and
MMC has the potential in the future. In view of the growing need for sustainable construction
projects is the assumption that they will benefit from an even larger extent than at present.
The success of this technology depends on how they use the possibilities architects, planners
and building engineers

39
REFERENCES
1. M. Arif, 2009 ―Editorial—special issue on offsite manufacturing,‖ Construction
Innovation, vol. 9, no. 1, pp. 5–6.
2. Bakens, W. (1997). ―International trends in building construction research.” Journal
of Construction Engineering and Management, 123 (2), 102-124.
3. Blismas, N., ed. (2007). Off-site manufacture in Australia: Current state and future
directions, Cooperative Research Centre for Construction Innovation.
4. Kozlovska M and Zupova L 2013 Modern methods of construction as a challenge for
energy efficiency buildings Proc. of 13th Int. Multidisciplinary Scientific Geoconf.:
Nano, bio and green - technologies for a sustainable future, (Albena, Bulgaria) 677-
684
5. Doherty, (2011) T. Modern methods of Construction (MMC) & Eco-Building.
19p.Available:http://www.buildstore.co.uk/developers/sitefiles/pdfs/Introduction%20t
o%20MMC%20&%20Eco%20COnstruction%20%20Tim%20Doherty.pdf(26/10/201
3)
6. Mesaros P, Mandicak T, Selin J (2015) ,‖Modern methods for cost management in
construction enterprises”, Journal of Civil Engineering : Selected Scientific Papers.
10:111-120.
7. Alexander. C. (1959),“Perception and modular coordination.‖ RIBA J.,66(12), 425–
429.
8. Ross, K., Cartwright, P., and Novakovic, O. 2006.‖ A Guide to Modern Methods of
Construction”. Amersham:IHE BRE Press.
9. Hashemi, A. 2006. ―Modern Methods of Construction in the UK Housing Industry.”
Presented at Second Research Student Conference, Cardiff, UK.
10. W. Nadim, J.S. Goulding, Offsite production in the UK: the way forward A UK
construction industry perspective, Construction innovation, 10 (2010) 181-202.

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