120830 Smegal - Roxul Cladding Attachment presentation.pptx

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Roxul Building Science Consulting Day
Cladding Attachment–Laboratory Research and Design
August 30, 2012
  University of Waterloo – Env. Eng’g   Met Dr. Straube Jonathan Smegal Building Science Corpora:on   Masters in Building Science   Drainage in Small Cavi:es in Wall Systems   Instrumenta:on/Research Cladding Attachment - Laboratory
Research and Design
  Hired by BSC   Laboratory research, test huts, site inves:ga:ons, air leakage tes:ng, Roxul Energy Design Centre Event – August 30, 2012
Acknowledgements Presenta:on Outline   Roxul   United States Department of Energy Building America Program   BSC Colleagues   Review Perfect Wall   Cladding ASachment   Laboratory Research/Design Criteria   Short term deflec:on   Long term deflec:on   Exterior tes:ng   Masonry Cladding ASachment Roxul Energy Design Centre Event – August 30, 2012
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Roxul Energy Design Centre Event – August 30, 2012
© buildingscience.com
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1980s ON – a “weird” builder The “Perfect” Wall   Increase overall thermal performance   Combina:on of exterior and cavity insula:on   Minimize thermal bridges   Minimize poten:al for air leakage condensa:on   Improve air :ghtness?   Improve rainwater management? Roxul Energy Design Centre Event – August 30, 2012
1990s ON – a “good” builder 1995 – 2pcf Roxul Energy Design Centre Event – August 30, 2012
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2000s ON – a “typical” builder August 30, 2012
Cladding ASachment   For insula:on 1.5” or less – direct aSachment of cladding though insula:on back to the structure is oèn prac:cal   For insula:on greater than 1.5” – a secondary cladding support system is oèn needed.   Not prac:cal to aSach cladding through thick insula:on layers   Building Codes have moved to con:nuous insula:on in many cases over North America   There are many op:ons to structurally support cladding with thick layers of exterior insula:on. There are issues with many of them.  
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Thermal bridging (eg. Z-‐furring) Costly Proprietary Systems Custom solu:ons Minimum number of holes in control layers of Perfect Wall Roxul Energy Design Centre Event – August 30, 2012
Cladding ASachment Furring Strips (strapping)   Furring strips can be aSached through the insula:on to the structure of the building which provides a loca:on to aSach the strapping normally.   Not only does this provide cladding aSachment but also has the benefit of producing a ¾” cavity that provides a capillary break, drainage, and ven:la:on drying   Our experience in low rise residen:al is that these furring strips do not need to be pressure treated. Roxul Energy Design Centre Event – August 30, 2012
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Cladding ASachment ~17 years ago Roxul Energy Design Centre Event – August 30, 2012
Building Science Corpora:on Roxul Energy Design Centre Event – August 30, 2012
Joseph Lstiburek
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2000s MA – a “High-‐R” assembly Building Science Corpora:on Smegal
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2000s – “High-‐R” retrofit August 30, 2012
Juneau, AK (2005) (BSI-‐031 Building in Extreme Cold) Roxul Energy Design Centre Event – August 30, 2012
Concerns of Cladding Movement   All of the insula:on materials aren’t structural materials/products. The general concern with all of them is that they are all rela:vely so`.  We started gejng ques:ons from product manufacturers and designers about the risk of cladding creep. What will happen?  We s:ll get ques:ons about this to this day.  “As you may recall we will have 1” of insula:on board beneath the stucco. (CA building code will require 2” in 2014). When this first came up a couple of years ago every stucco contractor expressed concern about the stucco falling off the studs due to weight and the length of the nails, this defines the so called “nailing problem”.” Roxul Energy Design Centre Event – August 30, 2012
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Discrete Load Components Cladding aSachments   Discrete Load Components   Insula:ng on exterior is not a structural challenge … unless you use the wrong model   Bending does maSer, but only at high deflec:ons Roxul Energy Design Centre Event – August 30, 2012
Previous Research Foam sheathing field tes:ng   Started thinking about this in 2008   At this :me there was no informa:on available on the movement of cladding or strapping fastened through exterior insula:on Roxul Energy Design Centre Event – August 30, 2012
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Direct ASachment Through Insula:on Direct ASachment Through Insula:on   2010   “Does the insula:on provide any addi:onal capacity for the system?”   BSC staff test   System loaded with 4” of rigid mineral fiber insula:on between furring and wall Roxul Energy Design Centre Event – August 30, 2012
BSC Laboratory Research Direct ASachment Through Insula:on   Develop a method to determine the predicted deflec:on under various cladding weights on wood framed wall assemblies.   What variables to test?   Insula:on type, thickness, fastener spacing, type, furring spacing etc.   Reasonable worst case scenario standard construc:on. (maximum safety factor)   Off the shelf components   Fasteners, strapping (1x3) Roxul Energy Design Centre Event – August 30, 2012
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Short Term Deflec:on Tes:ng August 30, 2012
Applying weight to strapping   -‐ Wood frame, OSB, plas:c housewrap, insula:on, 1x3 strapping Roxul Energy Design Centre Event – August 30, 2012
Strapping ASachment Rockwool 1x3 furring @ 24” o.c. #10 screws @ 16” o.c. ver:cally Result: 20 psf (640lb adhered stone) cladding weight with < 2/100” deflec:on report is on Roxul website Roxul Energy Design Centre Event – August 30, 2012
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Screw Comparison Tes:ng Results – Summary   Lightweight claddings (vinyl, wood, fiber cement) have very liSle movement (~1/200”)   For lightweight claddings deflec:on does not even approach proposed deflec:on limit (1/16”)   Tes:ng results in line with long history of performance of buildings constructed with this assembly   So what insula:on do you use?   Heavier briSle claddings (stucco, adhered stone veneers) ini:al deflec:on is not as important as long term deflec-on Roxul Energy Design Centre Event – August 30, 2012
Repeatability Fastener Type Roxul Energy Design Centre Event – August 30, 2012
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Addi:onal Ques:ons Gravity Load Response Tes:ng (2012)
  The exact mechanisms of the load deflec:on resistance are not well quan:fied   Discrete load components are theorized but have not been measured   Important to understand factors that affect the development of system capacity to examine means to design the aSachment systems   Discrete Load Components Roxul Energy Design Centre Event – August 30, 2012
Discrete Load Component Testing
Discrete Load Component Testing
  Series of tests to measure material proper:es  
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  Pre-‐compression (clamping) forces Coefficients of fric:on Compression modulus of insula:on   Forces imposed on the system by :ghtening of the screw fasteners that hold the wood furring in place   Tested using common #10 Wood Screws   Small scale test to try to isolate the discrete func:ons  
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Screw bending/wood bearing Strut and :e model Fric:on between layers  
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Due to pre-‐compression (clamping) forces Due to rota:onal forces Roxul Energy Design Centre Event – August 30, 2012
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Further Tes:ng August 30, 2012
Masonry Cladding ASachment   Previous tes:ng en:rely focused on wood framed walls, typically residen:al construc:on   There is a plan to test some steel stud walls, with DensGlass, Roxul CIS insula:on, and various cladding aSachment strategies.   The same overall goals will apply, cost effec:ve, reduce thermal bridging, common materials Roxul Energy Design Centre Event – August 30, 2012
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Further Informa:on   Deflec:on report for Roxul   hSp://www.roxul.com/residen:al/products/
roxul+comfortboard+is   Listed under “downloads”   BSC Website   www.buildingscience.com   Research Report 1204 – P.Baker Roxul Energy Design Centre Event – August 30, 2012
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120830 Smegal - Roxul Cladding Attachment presentation.pptx

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