Community: Energy efficiency and durability

Q & A Instructions

[Click map to enlarge]

The web site has a wealth of articles on a wide variety of construction topics. Before posting your question, you may want to check out the articles on this page: How To Do Everything. You just might discover an article there that provides the information you seek.

Please register for a free account or sign in to ask and answer green building questions.

If you want to post a question, the usual rules of courtesy apply:
1. Be nice.
2. If you can't be nice, be polite.
3. If you can't be nice or polite — well, please be brief.

To attach a photo or illustration: Under the box labeled “More explanation,” look for the words “File attachments.” Click that, and you should be able to attach a photo.

Thanks for joining the conversation!

4 Answers

New house question

After a lifetime in the Southwest, we are building our first home in a Zone 6 area (Northwest Montana near the Canadian Border). I stumbled across this website accidentally, and have read everything I can regarding insulation/ barrier techniques, but was hoping for some clarification.

Asked By Bill C | Nov 30 15
3 Answers

Unvented attic and wall?

Zone 3, 12/12 pitch roof, Galvalume color roof.
Talked to insulation contractor and discussed options.

2x6 walls = Hardie lap siding, 3/8" rainscreen, Tyvek, OSB, air sealing, BIB insulation (R-23), 5/8" sheetrock.

2x8 cathedrial roof, unvented, with total elect units and ducting in kneewall area and spare room in the center = standing seam, membrane?, 7/16" OSB, 2 inch polyiso, membrane or taped joints?, 7/16" OSB, 7 inch open-cell or BIB insulation.
No venting.

Are we getting closer?

Asked By Quinton | Nov 29 15
7 Answers

Can I leave the fiberglass insulation in place and add 1/2-inch Rmax polyiso to the interior?

I am starting a renovation in a home with T-111 exterior siding, 2x4 walls, 3 1/2" fiberglass batts for insulation. Can I add 1/2" foil faced Rmax on the interior wall and then sheetrock? Is there a better way to increase the insulation/air sealing then what I 'm describing?

Asked By James | Nov 30 15
4 Answers

I may need to tear out some insulation

Ok..before I found this site and looked into the proper techniques of insulation I started insulating our basement rim joist/sill plate area because we were working on the house and I was losing tons of heat in this area. I insulated about 30' of the sill plate area with foil backed 3/4" JM insulation doubled 1.5" against the 8x8" sill beam.

Asked By Geoffrey Cook | Nov 30 15
6 Answers

Where to put the smart vapor retarder?

We are remodeling the second floor of our 1956 Cape in Williamsburg VA, climate zone 4. I need advice about where to incorporate the MemBrain smart vapor retarder in the roof and wall insulation stack up.

Roof stackup: Asphalt shingles- Durabuild synthetic underlayment-1x8 plank roof decking- approximately 1.5 inch airspace (ProVent running soffit to ridge vet)- 3.5 inches of Roxul R15 between the 2x6 rafters- 5.5 inches of Roxul R23 between 2x6 “mooney wall” furring running perpendicular to the rafters- sheetrock.

Asked By Chris | Nov 29 15
9 Answers

SIP walls insulating the floor joists

I'm attaching a picture posted by Insulspan, the SIP manufacturer we're getting a quote from. It shows the SIP wall on the edge of the basement wall with the floor joists on the inside edge, providing continuous insulation of the rim joist. Has anyone seen this done? I thought at least 4 inches of the floor joist had to rest on the basement wall to be structurally sound. I plan on using superior walls which are 10.25 in thick and 8.25 in SIPs.

Asked By Brian W | Nov 28 15
2 Answers

What is the most economical heat system for a 700 s.f. house with no furnace?

I have a relative who may have to give up her house due to illness/unemployment Her gas furnace went on the blink. To replace it would be $1800 +. What is the safest most economical method of heat to heat her 775 sf house. She closes off one room so actually 3 small rooms & a bath is what she would be heating. For now she is using an electric fireplace and two infrared heaters that are supposed to heat up to 1000 sf.
Thank you.

Asked By Ruby | Nov 30 15
3 Answers

Best practices for HRV on a budget

I am building a simple but efficient home in climate zone C4. It will be a 3 bedroom, 2000 sq ft home. with us living mostly in the upper half. I was originally planning on putting one or two panasonic spot ERVs in but am know thinking it might be better for overall air quality, efficiency, and spreading the heat from my two headed mini-split, to put a fully ducted HRV unit in. I have been looking at the Fantec FLEX100H, and the Lifebreath RNC 95. Money is a huge issue but the price difference between two panasonics and one of these units is not much.

Asked By Kail Zuschlag | Nov 29 15
6 Answers

Advice for HRV/ERV on a budget

I am in climate zone 4C and building a fairly efficient home on a really tight budget. I used flashing tape and sealed all seams in my sheathing and will hopefully have a really tight home. The house is two stories, each story just over a 1000 sq ft (2100 sq ft total), and the home is designed so the majority of the living space is upstairs. I was planning on installing a single Panasonic Spot HRV in a central place upstairs, but a mechanical contractor (who was trying to sell me something) has told me that this will not be sufficient. and has recommended a Lifebreath RNC 95.

Asked By Kail Zuschlag | Nov 12 15
1 Answer
Register for a free account and join the conversation

Get a free account and join the conversation!
Become a GBA PRO!