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22 Answers

What would you do? XPS or EPS or ISO?

I am building a 3000 sq foot home in northern ontario (zone 8 or 9) with about 9000 HHD.

I am weighing my options on this wall contruction type.
It will be a 2x6 frame with R24 blow in batt in wall cavity and exterior foam insualtion, 1x4 strapping and siding

After reading and calculating foam thicknesses(thanks Martin) I would like to get to R20 if possible for the foam giving me a total wall R40+ rating, will be detailing like a REMOTE wall (window bucks)

Assume all of these will be taped:
I have been able to find EPS 5" thick(R20) non faced - plain white stuff

In General questions | Asked By Brian Krmpotic | Mar 28 12
19 Answers

What is a cost-effective wall assembly?

it seems a variation of this building question gets asked a lot so forgive me... i am building a 600 sq. ft. home in the Rocky Mountains of British Columbia where the building code calls for poly on the warm side of the insulation.

i would like to get as close to R-40 for the walls as economically as possible. Seeing that the received opinion around the GBA is the tandem of polyethylene sheeting and exterior rigid foam is not ideal, what do the builders on this site recommend? Larsen truss seems fairly labour-intensive and rigid foam is expensive... Is a double stud wall the answer?

In General questions | Asked By erik olofsson | May 13 12
2 Answers

Has anyone experienced problems installing Hardi siding over Zip R ?

I am building a "high performance" home in S E Dallas. I am concerened about Hardi siding staying attached, long term, when it is nailed through 1/2" OSB with 1/2" foam (Zip R). The siding will be blind nailed, properly. I have heard complaints by others that the nails worked loose due to expansion and contraction of the foam, causing extensive warranty issues for the builder. Having an extensive background in framing and general carpentry, I am doubtful of this zip R product in this situation. I would like to hear from anyone who has used this product in the manner described.
Phillip McCloud

In Green building techniques | Asked By Phillip McCloud | May 15 12
7 Answers

I am rebuilding a house and the sill plate is below grade

I am putting new ZIP sheathing over the whole house but 10 inches is below grade. I was thinking of putting Durock below grade for the 10 inches but some say pressure treated plywood might be better? Either product will be treated with a waterproof coating and then 3 inches of rigid foam then a stone exterior which is best or can I use something else? The foundation is block they just build it below grade ...


In Green building techniques | Asked By michael kasales | May 14 12
6 Answers

Age-old question of insulation payback — only heating costs? Why not the costs of cooling?

I'm in lower NY state Zone 5 (just), I have R-38 batts in the ceiling and want to put plywood down after bringing insulation level up 6 inches (cellulose).

Now I've been looking all over Google for a payback calculator that handles both heating and cooling. I've seen the heating one on GBA. Or am I missing the fact that you don't need to worry about the cooling if you have heating?

Sorry if It seems like a trivial question, but trying to figure the payback but it seems strange to me I can only find a heating payback not one where cooling in involved.

Anyone's feedback is appreciated.

In Green building techniques | Asked By Darren Finch | May 14 12
1 Answer

"Metal shingles" vs "lifetime" asphalt

A local neighborhood's covenants forbids metal (standing seam) roofs. If I decide to build there, I'm looking for longevity and recycling and trying to anticipate life cylcle costs.

On the one hand, I'm thinking of the GAF Timberline "cool roof" asphalt shingle with a "limited lifetime" warranty. Locally prices run about $160/sq.

But I've also found these: "Stone Coated Metal Shingles." There are several mfgs online. But I haven't found local contractors who have used them or who know about them. They seem to run between $250 -- $300/sq.

In Green products and materials | Asked By JoeW N GA Zone 3A | May 14 12
1 Answer

Is it OK to use spray foam on the back of a plaster wall and then fill the stud bays with fiberglass?

First, a little background: I am a plumbing, heating, and cooling contractor in Wilmington, DE. I own a circa 1874 balloon-framed house.

I am in the planning stages of my renovations. The wood lath plaster walls are in great shape, so I do not want to tear them out. As I’m sure you all have deduced, my house has no insulation except in the attic.

In Energy efficiency and durability | Asked By Shawn Woodrow | May 14 12
2 Answers

How to seal a crawl space in new constuction?

My idea is to put down 10-mil poly before pouring the footings and run the poly into the footings.

Will moisture from the concrete walls be a problem? Is there a better way?

In Green building techniques | Asked By larry ogden | May 13 12
26 Answers

Using polyisocyanurate insulation on the exterior of a home

I just read one of the discussions’ on the use of polyisocyanurate insulation on the exterior of a home and how it acts as a vapor barrier and not to use it because it doesn't breath, thus resulting in potential condensation and mold problems within the walls. My concern is that I am currently getting ready to reside my house and I have already installed this on 50% of my home. I wanted to only add 1.5" thick foam to work with my 8" windows jams that I have upgraded to So I wanted the most R value possible from a foam. And polyiso gave this and It was also cheaper then the 2" XPS.

In General questions | Asked By Shane Kingston | Jul 3 11
24 Answers

Is a thin layer of rigid foam better or worse than nothing?

I am building near Madison, WI. Our house plan has walls that consist of (outside-in): Cedar or Hardieplank, tyvek, 7/16 OSB, 16" on center-studs, R23 bib insulation, 6 mil vapor barrier, drywall. My question is whether 0.5" of rigid foam insulation added to the exterior, inside the Tyvek will do more harm than good. I gather it will reduce thermal bridging, but it is too thin and may lead to moisture problems. I know 1.5 to 2" of rigid foam is the correct thickness. So the question is, should I just ditch the foam?

Thanks in advance.

In Energy efficiency and durability | Asked By Adam Bayliss | May 6 12
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