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42 Answers

Heat-pump water heater vs. instantaneous water heater

Hey Martin;
New member and my first question! I've been following blogs, become a fan, and I'm on board/planning to build with exterior rigid board, using a mini-split, and concrete floors for mass.

In Energy efficiency and durability | Asked By steven bumpus | Jul 2 10
3 Answers

Inside vs outside basement waterproofing

What's generally a "greener" approach to old basement waterproofing, outside or inside?

In General questions | Asked By Andrei Sosnovsky | Aug 5 10
4 Answers

Dow Expanding foam

I have read several posts regarding off gassing off 2 part foams both closed and open cell....However my question specifically relates to using the Great Stuff Dow Expanding foam around HVAC supply vents. My concern is any off gassing that may occur around these supply vents if I use this foam. I have some minor gaps that I was going to seal to enhance the air barrier. But have concerns regarding any off gassing AFTER the foam has completely cured.

Anyone have any insights into this.

In General questions | Asked By matt | Jul 14 10
38 Answers

Too many vapor barriers! Help!

This is the exterior wall assembly on this house: Vinyl siding, 1" polyiso, then flash and batt (1" closed cell in cavity. Then clear plastic was applied on the interior face of the wall. I'm thinking that has to go. What are our options? Is it possible to vent the plastic with strategic slits in the plastic? The drywaller is scheduled for next week, and I just pointed this out to the owner today. Thanks in advance for any help I can pass on to add weight to my advice to him!

In Green building techniques | Asked By Sandra Heiser | Jul 27 10
21 Answers

Outside to inside perm ratio for mixed-humid climate?

I've read several posts lately mentioning a "5:1 outside to inside perm ratio with the goal of creating walls that can dry to the outside" for cold climates. Does anyone know what the ratio (along this line of thinking) would be for mixed-humid climates? It seems the goal would be to dry to both sides...but it also seems that opens the chance for moisture problems at both extremes of the year- we get 90 degree summer days with a good deal of humidity and single digit winter nights.

In Energy efficiency and durability | Asked By Hunter Dendy | Jul 30 10
4 Answers

I'm considering using rigid insulation under a metal roof with open rafters at the interior? Can I reach an R-30 value?

In a mixed climate area in Northern California (Lake County) where the summer temps can often reach over 100 and the winter temps fall below 32 at times, can I effectively reach the required R-30 insulation requirements with a metal roof over rigid insulation and an open rafter interior situation?

In General questions | Asked By william greineder | Aug 3 10
5 Answers

Existing cedar sided walls nailed to studs without building paper

We're remodeling a garage into a studio and want to "seal" (while allowing breathing) the exterior walls and then insulate. The siding is in pretty good shape (a few cracks) and is nailed directly to the studs. What is best for sealing the cracks? And can we insulate without building paper? Is there a way to install a wrap of some sort without removing the siding?

In Energy efficiency and durability | Asked By Julie | Aug 3 10
3 Answers

Best looking fiber cement shingle?

Would love recommendations on the best looking fiber cement SHINGLE siding.. so far have researched James Hardie, Nichiha, Certainteed.. and now found out about a rustic line shingle that Certainteed sells direct to BuildDirect.com. Cerber makes the treatment on the top of this shingle.
Thanks for your advice!

In Green products and materials | Asked By Karen Miller | Aug 3 10
3 Answers

Will you be able to afford to replace your shingles?

Came across an article on the cost of asphalt going forward that should be food for thought for builders interested in ensuring that homeowners can afford to stay in their homes in the long run. Since asphalt shingles are the predominant roofing choice I thought the following article might make people reconsider roof design going forward. Essentially asphalt is going to get more expensive , so shingles will cost more!

In Energy efficiency and durability | Asked By Andrew Henry | Aug 2 10
2 Answers

Exterior rigid foam protection

Hi, I am in the middle of building a home. The contractor has placed one-inch rigid foam insulation of the exterior of the home. Vinyl siding is going over this. At the bottom of the house, where the siding stops, you can reach under and feel the foam insulation. It is about 2 feet above grade.

Do I need to seal the bottom of the foam to prevent any critters from getting in, and if so how?

In General questions | Asked By Chris Johnston | Aug 2 10
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