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Unbuild It | Episode 162: Back to Basics: Air Control Layers Explained
The boys come up with some great generalities for at least three of the control layers in this episode:
- Staying in the same plane makes it easier to achieve continuity.
- Easier to install means greater chance of success.
- Combining control layers (in one component or material) means if you get continuity in one control layer, you get it in the next.
- Eliminate confused spaces: every space is either inside or outside the building (examples: attics, crawlspaces...).
And specific to air control:
- Blower doors do not lie: it is the best and the only way to really know how airtight your building is.
- Use blower doors quantitatively (the ACH50) but, just as importantly, find the leaks--how many, how big, locations (qualitative blower door results).
- Rarely can just one blower door test cut it - opportunities arise early and later during construction to increase airtightness.
- Air leaks are based on these phenomena: wind, stack effect, fans. Understand and respect each one.
- Two half-assed air control layers do not equal one good one.
- In renovation: blower door test 1st; air seal 2nd; THEN insulate.
Huge thanks to our episode sponsor, Diamond Kote. Learn more at: https://diamondkotesiding.com/
PETE'S RESOURCES:
- EPA – Moisture Control Guidance for Building Design, Construction, and Maintenance: https://www.epa.gov/indoor-air-quality-iaq/moisture-control-guidance-building-design-construction-and-maintenance-0
- Energy Star Thermal Bypass Checklist: https://basc.pnnl.gov/library/thermal-bypass-checklist-guide
- "A House Needs to Breathe...Or Does It? An Introduction to Building Science" (Allison Bailes): https://www.amazon.com/dp/1958711128?lv=shuf&channelId=500&plpRedirect=mhFallback
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