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4 Answers

Vapor permeability and SRI for unvented roof?

Building a new home, Climate Zone 5. Roof will be Uvented. Underside of rafters will be insulated with closed cell spray foam R-49 which will serve as A/V barrier also. Roofing is asphalt shingles. Most of roof is 12:12 cathedral with 5:12 dormers, with some minor attic area that will contain A/C ductwork. Overhangs are 16".

In Energy efficiency and durability | Asked By Julie Brown | Apr 13 18
6 Answers

Roof assembly

I’m insulating the roof of my log cabin in northern MN, zone 7. Trying to get to r49 topped with standing seam metal. Question is what underlayment do I put on the first layer of decking under the insulation and what do I put on the sheathing on top just under the metal? Also, vent the metal or not? Thank you, Andy

In GBA Pro help | Asked By user-6872567 | Apr 12 18
4 Answers

Searching for pretty good builder

I am in the planning stage for a 2,000 square foot pretty good house. It will be built in the outer reaches of the Atlanta metro. Recommendations can be posted here or emailed to joknapp2000 at yahoo dot com.

In GBA Pro help | Asked By Steve Knapp CZ 3A Georgia | Apr 11 18
10 Answers

Foundation insulation & moisture protection

I would like to insulate and protect my basement foundation walls using a water based spray on waterproofing, XPS insulation board, and a dimple mat. In what order would they be fastened to the wall? I feel like the insulation should go on after the waterproofing for it to be effective as an insulator.

In Green building techniques | Asked By Bryanw511 | Apr 10 18
2 Answers

LEED Certification process questions

Hey GBA'ers.

Have any of you gotten a building LEED certified?

I have been emailing and calling the Canadian Lakesideca Council (I'm located in Toronto), but they're not getting back to me. So I figure I'll just ask the community that actually helps people build green.

Just want to know what the process is, as in, do they need to do inspections during the build? Or is there just one inspection at the end, where they just take my word regarding what materials were used behind the walls. etc?

In General questions | Asked By Jamie B | Apr 12 18
9 Answers

Roofing Underlayment Options

I'm building a new house that will have a conditioned attic with open cell spray foam applied directly to the underside of the roof deck. The roof will be asphalt shingles. What is the best underlayment for this application? The climate zone is 2; hot/humid.

In General questions | Asked By E247 | Apr 11 18
29 Answers

Rainscreens with Roxul Comfortboard IS?

Hi all.
I am planning out my wall construction for a home in zone 6. Not much rain (15" annually), but plenty of snow in winter (56" annually). Hot (and mostly dry) in summer (80sF to low 100s), cold in winter (mostly lows in the single digits, but sometimes minus teens F). My house will not have much direct sun due to northern exposure and tree shading.

All that said, here is the wall I am considering:
- wall board
- 2x6 fir studs on 16" centers, Roxul Comfortbatt (R23) between the studs
- OSB, taped and sealed for my air barrier
- house wrap for vapor barrier

In Green building techniques | Asked By Mike B | Mar 20 16
3 Answers

Are Owens Corning Premium Cool Architectural Shingles worth the cost?

We are in zone 6 and planning not to vent our roof to wall new addition. We plan on using I-Joists with 4 inches of closed cell cell spray foam (R26) against the underside of the roof sheathing and fill the rest of the rafter cavity with an air-permeable insulation, additional fiberglass R25 underneath.
Wondering if it is worth the cost, (more than double) for this "cool" architectural shingles?
Thanks for any advice you can provide

In General questions | Asked By user-7005676 | Apr 12 18
1 Answer

Suggestions for tape for air sealing ISO (clean/used) foam board?

Building a house in SE Alaska, on an island, in zone 7. Thanks, Mike

In Energy efficiency and durability | Asked By Michael Parnell | Apr 12 18
5 Answers

Least evil of my wall system options

Border of Zone 4/5. I've read much of the material on this website about wall systems. While I have my desires for advanced framing techniques, including 2x6 24OC and thick foamboard outside insulation, these things aren't a realistic option with builders/subs in my area undergoing a building boom.

The path of least resistance is 2x4 or 2x6 16OC. The only other builder/framer reluctant possibility is Zip-R with built-in polyiso. My city uses the 2012 IECC, but has amended the walls from R20 or R13+5 down to R13. Yes, you read right, here in 2018, the Zone 4/5 wall code is R13.

In Green products and materials | Asked By Bruce Davis | Apr 11 18
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