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  1. An Overview of Current Alberta Above-grade Walls with Costing Information presented by Randy Kiez on behalf of SAITCHBA and PHBIA Builders’ BreakfastApril 2012

  2. SAIT Polytechnic - Green Building Technologieswas commissioned byAlberta Treasury Board and Enterprise to look at process and efficiencies for above-grade walls

  3. 1. A section on the Building Science of walls • 2. A selection of Wall Tear-Away sheets summarizing various wall / insulation assemblies • 3. Case Studies of [extensively experienced] companies focusing on their process(es) • 4. Costing Matrix that compares material costs and any savings that could be quantified through efficiencies The report includes:

  4. For baseline comparisons of performance and costing a typical Alberta house was used

  5. The NRCan HOT2000 tool was used for performance modeling

  6. Building Science Walls create a comfortable living space by resisting the flow of heat, air and moisture [vapour or liquid]. Walls define the shape and aesthetic appeal of a home. Walls are one component of a house but other influences such as geometry and air leakage also affect the overall energy efficiency.

  7. Geometry can play a significant role in the energy efficiency of a house.

  8. Air leakage has a larger influence on a tighter house than it has on a looser house

  9. A selection of industry experts participated in a ½ day information gathering session at SAIT and asked to share their knowledge of various wall systems based on five pre-established criteria. This information was compiled into ‘Tear-Away Sheets’ and the walls were rated based on the results. Wall Tear-Away Sheets

  10. The four walls that the panel assessed were: Wood frame and variations Structural Insulated panels (SIPs) Rigid Insulated Core (RIC) Insulating Concrete Form (ICF)

  11. The five criteria were: • Buildability • Durability • Performance • Cost • Marketability

  12. Conventional Framing

  13. OVERVIEW • 2x6 or 2x4 wood stud and plate construction • Typically 16 or 24 on-centre spacing • Cavity can be filled with any type of insulation • Buildable on-site or in factory (including insulation)

  14. BUILDABILITY (4 pts) • Workforce familiar with the techniques • Flexible to accommodate a variety of style designs • Easy to modify

  15. DURABILITY (1 pt) • Lifespan can be affected by assembly of moist materials • Can be affected by mechanical system pressurization • Exterior finish can severely affect drying ability

  16. PERFORMANCE (1 pt) • Difficult wall to air seal • External insulation is a widely used technique to reduce air leakage and thermal bridging but may affect cladding choices • Maximum practical achievable insulation levels • Recommend window /door installation trade training

  17. COST (4 pts) • Relatively inexpensive to build • Site construction subject to weather damage, theft and vandalism • Extraordinary professional services generally not required due to wide spread usage and knowledge

  18. MARKETABILITY (1 pts) • Greatest customer demand because of low initial purchase cost • Hardest to achieve high energy performance therefore hardest to market as ‘ energy efficient’ • Cost and common practice does not encourage change or innovation

  19. SCORE - Conventional Framing BUILDABILITY 4 DURABILITY 1PERFORMANCE 1COST 4MARKETABILITY 1TOTAL SCORE 11

  20. Alternate Wood Framing

  21. OVERVIEW • Thicker than conventional walls • Many types such as staggered stud and truss walls • Can be filled with different combinations and thicknesses of insulation for performance tuning • Designed to avoid thermal bridging and to accommodate high insulation R-values

  22. BUILDABILITY (3 pts) • Similar or identical to ‘conventional’ wall framing • More time to frame and insulate and heavier to lift • Staggered stud has widest usage and shares a heritage with current style apartment walls [8” considered by group easiest and most affordable] and can be factory built

  23. DURABILITY (3 pts) • Must apply good practice for air and vapour sealing • A thick wall may delay detection of water leaks • Thick wall can be used to advantage by setting back windows for rain control

  24. PERFORMANCE (4 pts) • Designed to minimize thermal bridging • Customizable to any thickness to accommodate high R-values • Some insulations can sag, compress or dislodge from the cavity compromising performance

  25. COST (3 pts) • Extra material costs include additional transport and handling fees • Increased labour to assemble and stand • May require engineering if outside the bounds of code practices

  26. MARKETABILITY (2 pts) • Increased comfort and reduced energy usage may counterbalance higher upfront costs • Could have wide appeal to buyers with environmental concerns especially if combined with bio-insulation materials • Reduced interior square footage can be offset with better interior design

  27. SCORE - Alternate Wood Framing BUILDABILITY 3 DURABILITY 3PERFORMANCE 4COST 3MARKETABILITY 2TOTAL SCORE 15

  28. Structural Insulated Panels (SIPs)

  29. OVERVIEW • Foam board or liquid foam sandwiched • between sheathing material • Held together by glue bonds between the foam and sheathing • Various sheathing materials available • Produced in a factory

  30. OVERVIEW • Two variations: • ‘Stressed skin’ • Limited dimensional wood in the cavity • Large panels of up to wall size lifted by crane • No CCMC evaluations at time of report writing • ii. ‘Internal structural’ • Dimensional wood in the cavity as per CCMC • Smaller panels which can be manhandled • Some CCMC evaluations at time of report writing

  31. BUILDABILITY (3 pts) • Can be stood quickly by trainable labour • Takes a commitment to understand product characteristics such as assembly at the connections points • Heavily dependant upon quality at the factory level

  32. DURABILITY (3 pts) • Requires conventional air sealing and product specific sealing techniques at the joints • Controlled thermal bridging reduces likelihood of condensation • Have a fifty year history of use and durability

  33. PERFORMANCE (4 pts) • Substantially reduced thermal bridging when compared to ‘conventional’ built walls • High potential for air leakage control • Monolithic core minimizes heat loss due to convection

  34. COST (2 pts) • Each install incurs engineering fees • Minimal theft due to uniqueness, size and just-in-time delivery • Depending on type must be craned into place

  35. MARKETABILITY (2 pts) • Good performance without compromising interior space • May face concerns that product is glue bonded and not mechanically bonded • Lower upfront cost

  36. SCORE - Structural Insulated Panels BUILDABILITY 3 DURABILITY 3PERFORMANCE 4COST 2MARKETABILITY 2TOTAL SCORE 14

  37. Rigid Insulating Core panels (RIC)

  38. OVERVIEW • Load bearing framing members imbedded internally in a core of foam insulation • Minimized thermal bridging • Produced in a factory

  39. OVERVIEW • Two variations: • ‘Wood framed’ • Fully code compliant wood framed assembly • Foam board insulating core used as a framing jig • Large panels of up to wall size lifted by crane • ii. ‘Steel framed’ • Commercial grade structural galvanized steel studs of engineered gauge and spacing pushed into a foam insulating core • Can be easily manhandled

  40. BUILDABILITY (4 pts) • Can be stood quickly • Some RIC manufacturers may supply their own stand-up crews • Wood RIC suitable for volume builders

  41. DURABILITY (3 pts) • Requires conventional air sealing and product specific sealing techniques at the joints • Controlled thermal bridging reduces likelihood of condensation • Standing quickly avoids potential for weather damage

  42. PERFORMANCE (3 pts) • Reduced thermal bridging when compared to ‘conventional’ built walls • High potential for air leakage control • Monolithic core minimizes heat loss due to convection

  43. COST (3 pts) • Minimal theft due to uniqueness, size and just-in-time delivery • Requires extra cost of a crane to lift into place • Minimal on-site waste to manage

  44. MARKETABILITY (2 pts) • Reduced lock up times means quicker possession • Thermal performance better than ‘conventional’ walls • Wood RIC code compliant which may be more appealing to buyers than alternative walls

  45. SCORE - Rigid Insulating Core panels BUILDABILITY 4DURABILITY 3PERFORMANCE 3COST 3MARKETABILITY 2TOTAL SCORE 15

  46. Insulating Concrete Forms (ICF)

  47. OVERVIEW • Essentially a concrete wall that uses a cribbing system of manufactured foam forming (polystyrene blocks) • Intrinsic insulation and structural combination

  48. BUILDABILITY (3 pts) • Relatively simple but requires training and experience • Fully code compliant • Can be good choice in remote locations

  49. DURABILITY (4 pts) • Proper concrete mix and pour techniques are critical • Excellent fire and structural durability • Good moisture control but still requires proper detailing at window, doors and cantilevers