Benjamin Obdyke AIA Ceu Presentation 10 01 09

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  • Welcome Personal introduction Recognition / acknowledgement of host Express appreciation of their taking time from their busy schedule to attend this CEU (Continuing Education Unit) focused on “Moisture Management in Sidewall Construction”. Reiterate that their attendance this is good for 1 credit in the Health Safety & Welfare [HS&W] category. No test is necessary. Pass around a “sign-in” sheet (available on-line from AIA). Ask them to please PRINT their name and, if they would like credit to be recorded with AIA for Continuing Ed, please provide their AIA number as well. Inform them that for those in attendance who are NOT members but who would still like to receive a certificate of completion, please ask them to indicate as such on the sign-in sheet.
  • It is NOT necessary to say anything about this slide. ( I often skip past this altogether.)
  • Read these S-L-O-W-L-Y. Although they seem elementary, by reading them slowly it will help the attendees disengage themselves from the busyness of their day and to focus on the topic at hand. To the end of the 3 rd bullet point, add “where warranted”.
  • (Ask for permission of the attendees to read this quote. Read the paragraph slowly to allow the info to stick) : “ Permit me to READ this first important slide. It is an except from a study published by the IRC which is the research arm of CMHC---The Canadian Mortgage & Housing Corporation---the leading code body in Canada. It will help to establish a common point of reference that will be foundational to our understanding as the presentation evolves.” Once you’ve read it through completely, call their attention to this important sentence… “ A wall assembly that is trouble-free in one area of the country may not perform adequately in another”. Make the following statement: “To illustrate the importance of this, let me ask the following question”: What does Reno, Nevada and Baton Rouge, Louisiana, have in common?” (Allow them 5-10 seconds to think. Some may offer an answer or two.) Answer: CASINOS. However, one thing they DON’T have in common is RAIN ! Reno receives about 4” of rain per year, whereas Baton Rouge often receives 4” of rain per hour! Yet the casinos built in Baton Rouge in the last 7 years were almost identical to the ones built in Reno a decade before. And excessive moisture intrusion severely compromised the structural integrity of much of the assemblies of those casinos resulting in failure long before the brunt of the Katrina’s fury hit !
  • (Ask for permission of the attendees to read this quote. Read the paragraph slowly to allow the info to stick) : “ Permit me to READ this first important slide. It is an except from a study published by the IRC which is the research arm of CMHC---The Canadian Mortgage & Housing Corporation---the leading code body in Canada. It will help to establish a common point of reference that will be foundational to our understanding as the presentation evolves.” Once you’ve read it through completely, call their attention to this important sentence… “ A wall assembly that is trouble-free in one area of the country may not perform adequately in another”. Make the following statement: “To illustrate the importance of this, let me ask the following question”: What does Reno, Nevada and Baton Rouge, Louisiana, have in common?” (Allow them 5-10 seconds to think. Some may offer an answer or two.) Answer: CASINOS. However, one thing they DON’T have in common is RAIN ! Reno receives about 4” of rain per year, whereas Baton Rouge often receives 4” of rain per hour! Yet the casinos built in Baton Rouge in the last 7 years were almost identical to the ones built in Reno a decade before. And excessive moisture intrusion severely compromised the structural integrity of much of the assemblies of those casinos resulting in failure long before the brunt of the Katrina’s fury hit !
  • (Ask for permission of the attendees to read this quote. Read the paragraph slowly to allow the info to stick) : “ Permit me to READ this first important slide. It is an except from a study published by the IRC which is the research arm of CMHC---The Canadian Mortgage & Housing Corporation---the leading code body in Canada. It will help to establish a common point of reference that will be foundational to our understanding as the presentation evolves.” Once you’ve read it through completely, call their attention to this important sentence… “ A wall assembly that is trouble-free in one area of the country may not perform adequately in another”. Make the following statement: “To illustrate the importance of this, let me ask the following question”: What does Reno, Nevada and Baton Rouge, Louisiana, have in common?” (Allow them 5-10 seconds to think. Some may offer an answer or two.) Answer: CASINOS. However, one thing they DON’T have in common is RAIN ! Reno receives about 4” of rain per year, whereas Baton Rouge often receives 4” of rain per hour! Yet the casinos built in Baton Rouge in the last 7 years were almost identical to the ones built in Reno a decade before. And excessive moisture intrusion severely compromised the structural integrity of much of the assemblies of those casinos resulting in failure long before the brunt of the Katrina’s fury hit !
  • (Ask for permission of the attendees to read this quote. Read the paragraph slowly to allow the info to stick) : “ Permit me to READ this first important slide. It is an except from a study published by the IRC which is the research arm of CMHC---The Canadian Mortgage & Housing Corporation---the leading code body in Canada. It will help to establish a common point of reference that will be foundational to our understanding as the presentation evolves.” Once you’ve read it through completely, call their attention to this important sentence… “ A wall assembly that is trouble-free in one area of the country may not perform adequately in another”. Make the following statement: “To illustrate the importance of this, let me ask the following question”: What does Reno, Nevada and Baton Rouge, Louisiana, have in common?” (Allow them 5-10 seconds to think. Some may offer an answer or two.) Answer: CASINOS. However, one thing they DON’T have in common is RAIN ! Reno receives about 4” of rain per year, whereas Baton Rouge often receives 4” of rain per hour! Yet the casinos built in Baton Rouge in the last 7 years were almost identical to the ones built in Reno a decade before. And excessive moisture intrusion severely compromised the structural integrity of much of the assemblies of those casinos resulting in failure long before the brunt of the Katrina’s fury hit !
  • (Ask for permission of the attendees to read this quote. Read the paragraph slowly to allow the info to stick) : “ Permit me to READ this first important slide. It is an except from a study published by the IRC which is the research arm of CMHC---The Canadian Mortgage & Housing Corporation---the leading code body in Canada. It will help to establish a common point of reference that will be foundational to our understanding as the presentation evolves.” Once you’ve read it through completely, call their attention to this important sentence… “ A wall assembly that is trouble-free in one area of the country may not perform adequately in another”. Make the following statement: “To illustrate the importance of this, let me ask the following question”: What does Reno, Nevada and Baton Rouge, Louisiana, have in common?” (Allow them 5-10 seconds to think. Some may offer an answer or two.) Answer: CASINOS. However, one thing they DON’T have in common is RAIN ! Reno receives about 4” of rain per year, whereas Baton Rouge often receives 4” of rain per hour! Yet the casinos built in Baton Rouge in the last 7 years were almost identical to the ones built in Reno a decade before. And excessive moisture intrusion severely compromised the structural integrity of much of the assemblies of those casinos resulting in failure long before the brunt of the Katrina’s fury hit !
  • (Ask for permission of the attendees to read this quote. Read the paragraph slowly to allow the info to stick) : “ Permit me to READ this first important slide. It is an except from a study published by the IRC which is the research arm of CMHC---The Canadian Mortgage & Housing Corporation---the leading code body in Canada. It will help to establish a common point of reference that will be foundational to our understanding as the presentation evolves.” Once you’ve read it through completely, call their attention to this important sentence… “ A wall assembly that is trouble-free in one area of the country may not perform adequately in another”. Make the following statement: “To illustrate the importance of this, let me ask the following question”: What does Reno, Nevada and Baton Rouge, Louisiana, have in common?” (Allow them 5-10 seconds to think. Some may offer an answer or two.) Answer: CASINOS. However, one thing they DON’T have in common is RAIN ! Reno receives about 4” of rain per year, whereas Baton Rouge often receives 4” of rain per hour! Yet the casinos built in Baton Rouge in the last 7 years were almost identical to the ones built in Reno a decade before. And excessive moisture intrusion severely compromised the structural integrity of much of the assemblies of those casinos resulting in failure long before the brunt of the Katrina’s fury hit !
  • (Ask for permission of the attendees to read this quote. Read the paragraph slowly to allow the info to stick) : “ Permit me to READ this first important slide. It is an except from a study published by the IRC which is the research arm of CMHC---The Canadian Mortgage & Housing Corporation---the leading code body in Canada. It will help to establish a common point of reference that will be foundational to our understanding as the presentation evolves.” Once you’ve read it through completely, call their attention to this important sentence… “ A wall assembly that is trouble-free in one area of the country may not perform adequately in another”. Make the following statement: “To illustrate the importance of this, let me ask the following question”: What does Reno, Nevada and Baton Rouge, Louisiana, have in common?” (Allow them 5-10 seconds to think. Some may offer an answer or two.) Answer: CASINOS. However, one thing they DON’T have in common is RAIN ! Reno receives about 4” of rain per year, whereas Baton Rouge often receives 4” of rain per hour! Yet the casinos built in Baton Rouge in the last 7 years were almost identical to the ones built in Reno a decade before. And excessive moisture intrusion severely compromised the structural integrity of much of the assemblies of those casinos resulting in failure long before the brunt of the Katrina’s fury hit !
  • This Detail Shows: Principles of Moisture Movement dictate that moisture migrates from areas of HIGH HUMIDITY to areas of LOW HUMIDITY, from WARM to COLD. In some areas of the country, such as the South, this may be a bigger issue problem than in others, such as New England for example. However, it has often been said by leading Building Scientists that moisture intrusion as a result of vapor diffusion can best be measured in spoonfuls. Whereas moisture intrusion as the result of…(advance to next slide)
  • … Wind Driven Rain can best be measured in BUCKET-FULLS ! Wind driven rain is the real culprit in most cases. “ In addition to joints and laps, hose bibs, utility cutouts, and dryer vents can be a major source of entry where the caulk has failed under the UV (Ultra-violet) load or the settling of the house. All that is needed is a gap 1/64” inch for rain to be driven in.
  • So not only do we have a wind-load driving water into the wall, we also have simple physics actually siphoning or drawing the water in.
  • A break-down in the surface is often only an outward manifestation of larger problem inside the wall assembly.
  • This photo shows when a problem is no longer a “punch-list” item. Now it’s often a “Health, Safety and Welfare” problem! Mold claims have driven insurance premiums for builders through the roof. For every $1.00 in premiums collected, insurers have had to pay out $3.00 in claims as of the end of 2005. It is projected to climb to $7.00 by 2007. Hence the reason for the huge increases in premiums witnessed by contractors in the last 36 months.
  • Read through the bullet points on the slide. After reading thru this, Add mold needs a food source and moisture to grow. The cellulose in the wood and paper faced gypsum provides the food and the moisture is present in the relative humidity. An Rh of 70% provides a perfect petri-dish.
  • Again, read these slowly. Often referred to as the “4-D’s of Moisture Management.” An example of deflections : over-hangs Drying (add): “and a mechanism whereby the rate of drying exceeds the rate of wetting . If the rate of wetting exceeds the rate of drying, accumulation occurs. This is a basic principle of moisture management which leading building scientists subscribe to.
  • No speaker notes.
  • In simplest terms, when you create an 1/8” airspace (or 125 mil) between the cladding and the shear wall you create a capillary break that neutralizes the ability of the wall to siphon water in during a rain event. That’s what differentiates a rainscreen from a drain-screen . Enhanced WRBs with ribs, crinkles or dimples may provide better drainage compared to a regular WRB however they don’t provide the minimum air-space necessary to create a capillary break. The greatest thickness of any WRB only measures only 15 - 18 mils in height!
  • This map shows rain fall regions across North America. Leading Building Scientists recommend that rainscreen assemblies be used wherever the annual rain fall exceeds 40” Point out the region the viewer is in, noting how much rainfall occurs in their locale The basic difference between a vented rainscreen and a fully ventilated drain-screen is that a vented drainscreen is only open at the bottom, to weep out accumulated water. A fully ventilated drain-screen is open at the bottom as well as the top allowing for air to enter in thru the top opening and flush the system in a convective fashion providing the maximum air for drainage & drying. Remember, the basic principle cited earlier that “ the rate of drying must exceed the rate of wetting”. Air movement is required for drying to take place.
  • Ask audience about the disadvantages of installing a rainscreen wall in this way
  • Make note of the disadvantages above Another downsides of this practice is that 15 – 18 % of the wall is not ventilated as a result of the 1x3 furring 16” o.c. Even though the cost of the furring is relatively cheap, because of the labor to properly install the system, it typically costs around $1.25 The cost goes up significantly when ripped-down pressure treated CDX is used. $2.00 per sq ft is a common figure used by contractors when you figure the cost of anti-corrosive fasteners and labor into the equation
  • Shown here is Home Slicker. A product by Benjamin Obdyke and an example of “void space technology”. (Omit if presenting a true AIA presentation) It is proven to provide greater drainage & drying capability than wood strapping Installs in a fraction of the time Typical cost <$0.75 / sq ft 50 year warranty
  • Discuss the general installation sequence described in this illustration of a stucco application. Call exception to the use of a 2 nd layer of building paper used in this cutaway illustration to prevent clogging of channels by scratch-coat. (for stucco only)
  • Call attention to the use of fiberglass screen cloth used to prevent bugs / spiders from nesting in behind siding. This is a practice used with rain screen walls that are strapped out as well. Utilize HS display board for close-up
  • No speaker notes.
  • This is “boiler-plate” language found in CSI Manu-spec format. It is self-explanatory. After this slide ask if there are any questions.
  • After the Q&A, I often walk the attendees through our product literature packet and use it as an opportunity to present the other additions of the HS product line. If so, open up AIA CEU Presentation – PART 2 6-04-07
  • Benjamin Obdyke AIA Ceu Presentation 10 01 09

    1. 1. Pressure-equalized rainscreen wall system design for light-frame construction. Course # BOI 101 Learning Units: 1 (HS&W) Provider: J740
    2. 2. <ul><li>Benjamin Obdyke Incorporated is a Registered Provider with the American Institute of Architects Continuing Education Systems. Credit earned on completion of this program will be reported to CES Records for AIA members. Certificates of Completion for non-AIA members are available on request. </li></ul><ul><li>This program is registered with the AIA/CES for continuing professional education. As such, it does not include content that may be deemed or construed to be an approval of endorsement by the AIA of any material of construction or any method or manner of handling, using, distributing, or dealing in any material or product. Questions related to specific materials, methods, and services will be addressed at the conclusion of this presentation. </li></ul>
    3. 3. COPYRIGHT MATERIALS <ul><li>This presentation is protected by US and International copyright laws. Reproduction, distribution, display and use of the presentation without written permission of the speaker is prohibited. </li></ul><ul><li>© Benjamin Obdyke Incorporated 2009 </li></ul>
    4. 4. MOISTURE MANAGEMENT IN SIDEWALL CONSTRUCTION <ul><li>Presented By: Benjamin Obdyke Incorporated </li></ul><ul><li>400 Babylon Road, Suite A </li></ul><ul><li>Horsham, PA 19044 </li></ul><ul><li>800-523-5261 </li></ul><ul><li>www.benjaminobdyke.com </li></ul><ul><li>Description: Pressure-equalized rainscreen wall system design for light frame construction </li></ul><ul><li>MCE Info: Contact your respective governmental licensing & regulatory agency </li></ul><ul><li>Expiration date: 1 year from AIA Accreditation </li></ul>
    5. 5. LEARNING OBJECTIVES <ul><li>Recognize how moisture infiltrates the building skin through sidewall conditions. </li></ul><ul><li>Understand the implications of water infiltration into the building. </li></ul><ul><li>Determine appropriate ways to employ rainscreen principles for a variety of cladding systems. </li></ul>
    6. 6. AN INDUSTRY PERSPECTIVE (1) Cornick, S. and Rousseau, M.Z., “ Understanding the Severity of Climate Loads for Moisture-related Design of Walls ”, IRC Building Science Insight 2003 Seminar Series, Toronto, CA, Oct. 2003, pp.1 “ The fundamental function of the building envelope is its separation of the outside and the inside environments so that indoor conditions can be controlled to meet many requirements (for example, comfort and energy efficiency). The design and construction of durable, efficient walls requires consideration of climate loads to which these building components will be exposed. A wall assembly that is trouble-free in one area of country may not perform adequately in another. This is because although the building physics do not change, the heat, air, and moisture control strategies may need to integrate different levels of redundancy for different climate conditions. The severity of the climate for a building site cannot be changed, but it needs to be integrated in the design of the wall assemblies. Understanding the climate loads acting on building components is an important step towards effective design of moisture management strategies .” (1)
    7. 7. AN INDUSTRY PERSPECTIVE (1) Cornick, S. and Rousseau, M.Z., “ Understanding the Severity of Climate Loads for Moisture-related Design of Walls ”, IRC Building Science Insight 2003 Seminar Series, Toronto, CA, Oct. 2003, pp.1 “ The fundamental function of the building envelope is its separation of the outside and the inside environments so that indoor conditions can be controlled to meet many requirements (for example, comfort and energy efficiency). The design and construction of durable, efficient walls requires consideration of climate loads to which these building components will be exposed. A wall assembly that is trouble-free in one area of country may not perform adequately in another. This is because although the building physics do not change, the heat, air, and moisture control strategies may need to integrate different levels of redundancy for different climate conditions. The severity of the climate for a building site cannot be changed, but it needs to be integrated in the design of the wall assemblies. Understanding the climate loads acting on building components is an important step towards effective design of moisture management strategies .” (1)
    8. 8. AN INDUSTRY PERSPECTIVE (1) Cornick, S. and Rousseau, M.Z., “ Understanding the Severity of Climate Loads for Moisture-related Design of Walls ”, IRC Building Science Insight 2003 Seminar Series, Toronto, CA, Oct. 2003, pp.1 “ The fundamental function of the building envelope is its separation of the outside and the inside environments so that indoor conditions can be controlled to meet many requirements (for example, comfort and energy efficiency). The design and construction of durable, efficient walls requires consideration of climate loads to which these building components will be exposed. A wall assembly that is trouble-free in one area of country may not perform adequately in another. This is because although the building physics do not change, the heat, air, and moisture control strategies may need to integrate different levels of redundancy for different climate conditions. The severity of the climate for a building site cannot be changed, but it needs to be integrated in the design of the wall assemblies. Understanding the climate loads acting on building components is an important step towards effective design of moisture management strategies .” (1)
    9. 9. AN INDUSTRY PERSPECTIVE (1) Cornick, S. and Rousseau, M.Z., “ Understanding the Severity of Climate Loads for Moisture-related Design of Walls ”, IRC Building Science Insight 2003 Seminar Series, Toronto, CA, Oct. 2003, pp.1 “ The fundamental function of the building envelope is its separation of the outside and the inside environments so that indoor conditions can be controlled to meet many requirements (for example, comfort and energy efficiency). The design and construction of durable, efficient walls requires consideration of climate loads to which these building components will be exposed. A wall assembly that is trouble-free in one area of country may not perform adequately in another. This is because although the building physics do not change, the heat, air, and moisture control strategies may need to integrate different levels of redundancy for different climate conditions. The severity of the climate for a building site cannot be changed, but it needs to be integrated in the design of the wall assemblies. Understanding the climate loads acting on building components is an important step towards effective design of moisture management strategies .” (1)
    10. 10. AN INDUSTRY PERSPECTIVE (1) Cornick, S. and Rousseau, M.Z., “ Understanding the Severity of Climate Loads for Moisture-related Design of Walls ”, IRC Building Science Insight 2003 Seminar Series, Toronto, CA, Oct. 2003, pp.1 “ The fundamental function of the building envelope is its separation of the outside and the inside environments so that indoor conditions can be controlled to meet many requirements (for example, comfort and energy efficiency). The design and construction of durable, efficient walls requires consideration of climate loads to which these building components will be exposed. A wall assembly that is trouble-free in one area of country may not perform adequately in another. This is because although the building physics do not change, the heat, air, and moisture control strategies may need to integrate different levels of redundancy for different climate conditions. The severity of the climate for a building site cannot be changed, but it needs to be integrated in the design of the wall assemblies. Understanding the climate loads acting on building components is an important step towards effective design of moisture management strategies .” (1)
    11. 11. AN INDUSTRY PERSPECTIVE (1) Cornick, S. and Rousseau, M.Z., “ Understanding the Severity of Climate Loads for Moisture-related Design of Walls ”, IRC Building Science Insight 2003 Seminar Series, Toronto, CA, Oct. 2003, pp.1 “ The fundamental function of the building envelope is its separation of the outside and the inside environments so that indoor conditions can be controlled to meet many requirements (for example, comfort and energy efficiency). The design and construction of durable, efficient walls requires consideration of climate loads to which these building components will be exposed. A wall assembly that is trouble-free in one area of country may not perform adequately in another. This is because although the building physics do not change, the heat, air, and moisture control strategies may need to integrate different levels of redundancy for different climate conditions. The severity of the climate for a building site cannot be changed, but it needs to be integrated in the design of the wall assemblies. Understanding the climate loads acting on building components is an important step towards effective design of moisture management strategies .” (1)
    12. 12. AN INDUSTRY PERSPECTIVE (1) Cornick, S. and Rousseau, M.Z., “ Understanding the Severity of Climate Loads for Moisture-related Design of Walls ”, IRC Building Science Insight 2003 Seminar Series, Toronto, CA, Oct. 2003, pp.1 “ The fundamental function of the building envelope is its separation of the outside and the inside environments so that indoor conditions can be controlled to meet many requirements (for example, comfort and energy efficiency). The design and construction of durable, efficient walls requires consideration of climate loads to which these building components will be exposed. A wall assembly that is trouble-free in one area of country may not perform adequately in another. This is because although the building physics do not change, the heat, air, and moisture control strategies may need to integrate different levels of redundancy for different climate conditions. The severity of the climate for a building site cannot be changed, but it needs to be integrated in the design of the wall assemblies. Understanding the climate loads acting on building components is an important step towards effective design of moisture management strategies .” (1)
    13. 13. HOW DOES MOISTURE INFILTRATE THE BUILDING?
    14. 14. HOW DOES MOISTURE INFILTRATE THE BUILDING? <ul><li>High Humidity / Extreme Temperatures </li></ul><ul><ul><li>Vapor-diffusion: Moisture flow from warm to cold (transported by air movement through leaks / penetrations in the assembly) condensing on the colder surface. </li></ul></ul>
    15. 15. HOW DOES MOISTURE INFILTRATE THE BUILDING? <ul><li>Wind driven rain from the exterior can be forced into small penetrations in the cladding materials at joints, laps, hose-bibs, vents, utility cut-outs, electrical outlets, nail holes, etc. </li></ul>
    16. 16. WIND & RAIN ACTING TOGETHER CAUSE WATER INFILTRATION <ul><li>Wind can blow the rain sometimes horizontally into cracks and holes in the exterior walls. </li></ul><ul><li>Wind blowing around the building can create a negative pressure within the wall assembly that siphons water into the assembly. </li></ul><ul><li>“ Reservoir” type claddings (hygroscopic) are especially sensitive to this phenomena </li></ul>.
    17. 17. WHAT ARE THE RESULTS OF MOISTURE INFILTRATION?
    18. 18. WHAT ARE THE RESULTS OF MOISTURE INFILTRATION? <ul><li>Exterior Surfaces Deteriorate </li></ul><ul><li>Shortened service life of paints & stains (discoloration & peeling) </li></ul><ul><li>Extractive bleed of pine & cedar resins </li></ul><ul><li>Surfactant migration onto WRB </li></ul>
    19. 19. SHORTENED SERVICE LIFE OF PAINT
    20. 20. EXTRACTIVE BLEED (CEDAR)
    21. 21. EXTRACTIVE BLEED (CEDAR)
    22. 22. EXTRACTIVE BLEED (CEDAR)
    23. 23. EXAMPLE OF SURFACTANT MIGRATION ONTO WRB (STUCCO)
    24. 24. WHAT ARE THE RESULTS OF MOISTURE INFILTRATION? <ul><li>Structural Damage </li></ul><ul><ul><li>Water can also undermine the structural integrity of a building, causing an unsafe environment to work and live in. </li></ul></ul>
    25. 26. TWO & THREE COAT STUCCO FAILURES
    26. 27. WHAT ARE THE RESULTS OF MOISTURE INFILTRATION? <ul><li>Mold – Mildew – Rot </li></ul><ul><ul><li>Mold and Mildew spores exist in the environment. </li></ul></ul><ul><ul><li>Wet wood and gypsum products create a food source for the mold and mildew to grow. </li></ul></ul><ul><ul><li>As mold and mildew grow they cause the wall system to rot. </li></ul></ul><ul><ul><li>Interior mold and mildew create a condition called “sick building syndrome” that can be a health hazard to people with allergies. </li></ul></ul>
    27. 28. <ul><li>Mold Needs: </li></ul><ul><ul><li>Food </li></ul></ul><ul><ul><li>Moisture 70% RH </li></ul></ul>
    28. 29. WHAT MAKES MOLD? <ul><li>“ 90% of all mold cases are related to WATER leaking through exterior finishes” </li></ul><ul><li>BUILDER Magazine , May, 2002 </li></ul>
    29. 30. MOISTURE MANAGEMENT METHODS
    30. 31. MOISTURE MANAGEMENT METHODS <ul><li>Deflection </li></ul><ul><ul><li>Use architectural elements to keep water from entering wall system. </li></ul></ul><ul><li>Drying </li></ul><ul><ul><li>Wall assembly allows water to evaporate rather than penetrate. </li></ul></ul><ul><li>Drainage </li></ul><ul><ul><li>Rainscreen type assemblies used to remove water from system. </li></ul></ul><ul><li>Durability </li></ul><ul><ul><li>Quality of construction materials is a significant factor in overall success of the rainscreen system. </li></ul></ul>
    31. 32. RAINSCREEN TECHNOLOGY <ul><li>Where Did Rainscreens Originally Come From? </li></ul><ul><ul><li>Originally developed for use in masonry construction, a rainscreen is a pressure equalized airspace between the structural envelope and the exterior cladding that promotes drainage of moisture from the assembly. Rainscreens were originally designed to “ drain the rain ” by controlling the powerful forces wetting the wall. </li></ul></ul>
    32. 33. PRESSURE EQUALIZED RAINSCREEN WALL PRINCIPLES <ul><li>How Rainscreens Work </li></ul><ul><li>The difference in air pressures across the exterior cladding is a significant force which causes infiltration of air and water on windward facades. The equalization of this pressure difference neutralizes the forces that draw water into the assembly. In addition, the airspace (minimum 1/8”) de-couples most of the cladding from the shear-wall reducing the capillary action of bulk water bridging onto the WRB. </li></ul>
    33. 34. <ul><li>“ The use of rainscreen assemblies </li></ul><ul><li>will eliminate the driving force </li></ul><ul><li>that causes water to leak into the wall.” </li></ul><ul><li>APA-The Engineered Wood Association </li></ul><ul><li>“ Build a Better Home” (2002) </li></ul>
    34. 35. WHERE TO USE RAINSCREENS Rainscreen systems (drainage planes with ventilated air spaces) should be used whenever average rainfall is greater than 40 inches.” Joseph Lstiburek, Ph.D,, P.Eng. Building Science Corp.
    35. 36. TRADITIONAL RAINSCREEN ASSEMBLY <ul><li>The traditional way of creating a rainscreen wall: </li></ul><ul><ul><li>Place lathe strips or 1x P.T. dimensional lumber, vertically at 8”, 12”, 16”or 24”centers </li></ul></ul><ul><ul><li>Attach cladding to the wood strips </li></ul></ul>
    36. 37. TRADITIONAL RAINSCREEN ASSEMBLY <ul><li>Disadvantages of Traditional Rainscreen Assembly: </li></ul><ul><ul><li>Material / Labor costs ($1.25 - $2.00 / sq. ft.) </li></ul></ul><ul><ul><li>Difficult to detail around penetrations </li></ul></ul><ul><ul><li>Fastener costs because of new treated lumber Alkaline Copper Quat (ACQ), or Copper Azole </li></ul></ul><ul><ul><li>Creates hot-spots and thermal bridging along stud locations </li></ul></ul><ul><ul><li>Ballooning of housewrap leads to reduced air movement in intended rainscreen cavity </li></ul></ul><ul><ul><li>Cupping & bowing of furring strips leads to premature failure of coating </li></ul></ul><ul><ul><li>Wood-to-wood contact traps moisture, supports growth of mold and causes “ghosting” or vertical telegraphing of furring locations to outside surfaces </li></ul></ul><ul><ul><li>Inconsistent performance </li></ul></ul>
    37. 38. <ul><li>“ Rainscreens offer exceptional value to </li></ul><ul><li>design professionals seeking liability protection , </li></ul><ul><li>builders wanting to avoid callbacks, and </li></ul><ul><li>homeowners looking for comfort.” </li></ul><ul><li>NAHB Research Center </li></ul><ul><li>“ Deterring rainwater intrusion into walls” (2005) </li></ul>
    38. 39. IMPROVEMENTS IN MOISTURE MANAGEMENT METHODS <ul><li>“ Void space technology ” utilizes a continuous plastic matrix to create the necessary air space in a rainscreen wall assembly that offers accelerated drying and enhanced drainage characteristics over traditional methods . The benefit of this technology is improved performance and cost-effectiveness. </li></ul>
    39. 40. MOISTURE MANAGEMENT METHODS <ul><li>A vented and continuous rainscreen barrier may be placed behind many exterior finish materials including: </li></ul><ul><ul><li>Wood Siding </li></ul></ul><ul><ul><li>Stucco </li></ul></ul><ul><ul><li>EIFS </li></ul></ul><ul><ul><li>Cement Fiber Sidings </li></ul></ul><ul><ul><li>Hardboard Siding </li></ul></ul><ul><ul><li>Stone Veneer </li></ul></ul><ul><ul><li>Shingles </li></ul></ul><ul><ul><li>Vinyl Siding </li></ul></ul>
    40. 41. MOISTURE MANAGEMENT METHODS <ul><li>Top and bottom of the vented rainscreen barrier cavity must be ventilated to allow moisture to escape and to equalize the pressure in the drainage cavity. </li></ul>
    41. 42. FLASHING DETAIL AROUND WINDOWS
    42. 43. OTHER MOISTURE MANAGEMENT METHODS <ul><li>Stucco </li></ul><ul><ul><li>Special housewrap materials designed with a corrugated face to facilitate moisture drainage . </li></ul></ul><ul><ul><ul><li>Typically housewrap is not designed as a pressure equalized system. </li></ul></ul></ul><ul><li>EIFS </li></ul><ul><ul><li>Several EIFS manufacturers have available a grooved backed insulation available to provide channels for moisture drainage. </li></ul></ul><ul><ul><ul><li>Generally not designed as a pressure equalized system. </li></ul></ul></ul><ul><ul><li>Void space technology is now available from many EIFS manufacturers. </li></ul></ul>
    43. 44. SPECIFICATION CONSIDERATIONS <ul><li>Vented rainscreen barrier materials maybe specified in a narrow-scope section such as Section 07460 – Sidewall Rainscreen Membrane. </li></ul><ul><ul><li>It is critical that this section be cross-referenced to other sections utilizing or interfacing with the vented rainscreen barrier. </li></ul></ul><ul><ul><li>This has the advantage of indicating materials and methods in one place. </li></ul></ul><ul><ul><li>It has potential disadvantage of not being picked up by each of the bidders in whose assemblies it is used. </li></ul></ul><ul><li>Alternatively, vented rainscreen barrier materials maybe specified in each of the sidewall system assemblies utilized on the project. </li></ul><ul><ul><li>The advantage is that each bidder must include the vented rainscreen barrier in their work. </li></ul></ul><ul><ul><li>A disadvantage maybe that modifications to individual sections could create conflicts or differences in how the vented rainscreen barrier material is installed. </li></ul></ul>
    44. 45. Thank you for your time! <ul><li>This concludes The American Institute of Architects </li></ul><ul><li>Continuing Education Systems Program. </li></ul>Questions? 800-523-5261 www.benjaminobdyke.com

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