Difference between revisions of "Walls and insulation"
From Green Garage Detroit
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Because we were designing a [[Super Insulated Building Envelope]], our wall system design was extremely important. Our goals included: | Because we were designing a [[Super Insulated Building Envelope]], our wall system design was extremely important. Our goals included: | ||
− | * Minimize thermal bridging | + | * Minimize [[http://en.wikipedia.org/wiki/Thermal_bridge thermal bridging]]. |
* Reduce energy use of existing building by at least 70%. | * Reduce energy use of existing building by at least 70%. | ||
* Use envelope and insulation materials that do not harm building occupants or the environment. | * Use envelope and insulation materials that do not harm building occupants or the environment. |
Revision as of 19:41, 15 August 2012
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Contents
Sustainability goals for our wall system
Because we were designing a Super Insulated Building Envelope, our wall system design was extremely important. Our goals included:
- Minimize [thermal bridging].
- Reduce energy use of existing building by at least 70%.
- Use envelope and insulation materials that do not harm building occupants or the environment.
- Use envelope and insulation materials that are existing, recycled, and/or local materials wherever possible.
Wall design
- Historic side
Built second wall inside the brick/block walls to accommodate super insulation while preserving historic appearance and keep block from entering waste stream. Modeled wall system with WUFI software to determine how best to achieve high R-value and also deal with moisture within our super insulated wall assembly design
- Historic brick/block layer 8" thick
- Weep holes at base of wall to drain moisture from behind masonry layer
- Drainage plane 1" thick
- This air layer helps control thermal bridging by separating the inner wall from the outer wall
- Also helps control moisture build up in the wall by providing a path for condensation or rain water to run down to weep holes
- Firring blocks 1" thick
- Controls thermal bridging by holding stud wall away from drainage plane behind masonry
- Polyiso rigid foam board 2" thick, 2 layers with staggered seams (total of 4" thick)
- Cellulose blown-in insulation (and wood studs) 5" thick
- Absorbs and dissipates moisture like a living organism
- Contains fire retardant and mold inhibitors
- Gypsum wallboard 1" thick, 1/2" reused from existing, 1/2" new material
- Total thermal resistance for the walls is R-42
- Total wall thickness is 18.5"
- Historic brick/block layer 8" thick