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8 Answers

Roof Underlayment Perm Rating?

I am in my final push of re roofing. Martin, Thank you again for answering my earlier questions.

My cathedral ceiling timber frame from inside out has:

tongue and groove
vapor barrier


tongue and groove
vapor barrier
Metal Roof

We tore the shingles off to find a fair amount of air leakage and are strapping and adding venting to the assembly.

In General questions | Asked By T White | Jan 7 12
3 Answers

Thought y'all might enjoy this:

Goddess knows how this wonderful structure escaped the eagle eye of UK Building Regulation enforcement, but there is mention of beer brewing and that may have helped. Aficionados of creative structural design will enjoy the 'reciprocal roof' - click on 'How' and then 'Roundwood Frame'.


In Green building techniques | Asked By James Morgan | Jan 7 12
1 Answer

How do you remove polyurethane spray foam?

Smell in attic from polyurethane foam soray

In General questions | Asked By Judy Gross | Jan 8 12
9 Answers

Attempting chainsaw/PERSIST retrofit... Help?

In June, I will be attempting a chainsaw retrofit of a 50-year old country cabin that faces ESE.

On the roof, we have vinyl shingles nailed into (I believe) tar papered 1x6 sheathing over 2 x 4 framing, and a chimney protrusion for boiler venting from the basement; that roof is on top of an unconditioned attic with about about 4-6" of blown-in cellulose on top of fiberglass batting on the attic floor. Hangover for eaves and rakes is approximately 18". There's also a dormer on the front for two fo our bedroom window.

In GBA Pro help | Asked By Satoshi Yano | Jan 7 12
4 Answers

High end shed: sealed envelope or open to roof?

Building a 12x15 multipurpose shed, most of the time just storing stuff unattended in Central Texas heat (and very rare freeze). Framed brick construction (light colored brick) with white metal roof, one window and french doors. Roof on top of radiant barrier. Attempting to beat the heat (9 mo/year and sometimes beyond 110 degrees), and condensation after fast temperature drops (sometimes >10 degrees/hour). No use of grid power (eventual plan is small solar system for lighting, fan, and radio). 3 months of the year there can be cold weather also, occasionally freezing.

In Energy efficiency and durability | Asked By Charles Peterson | May 18 11
6 Answers

Hybrid Sprayfoam


I am building a 600 sq foot cabin in US climate zone 5 with 2 by 6 wall construction. I have gotten a lot of great information from your web site and, as a result, the wall system from the outside in is 1.5 inches of XPS rigid foam insulation, housewrap, plywood. I am trying to decide what kind of insulation to use in the wall cavity.

In Energy efficiency and durability | Asked By Ron Baker | Jan 6 12
5 Answers

How does a vapor retarder work in a Northern climate?

I guess I'm asking a Building Science question here, but in a Northern Climate (e.g., 6A), What does an interior vapor retarder actually do, especially if the air barrier is at the sheathing layer for a typical 2x6 wall with fibrous insulation? I can understand an interior temperature of 68% with a relative humidity level of 35% (and the dew point that must be kept higher than any condensing surface, which seem to the real parameter of interest in all of these discussions), and I can understand the temperature gradient (and its associated "humidity" gradient increase with dew point change).

In General questions | Asked By Bob Manninen | Jan 6 12
22 Answers

Cathedral Ceilings Retrofit - Zone 5

Hi All,

I have house just north of Boston, in Zone 5. It is a contemporary home built in 1983 with nearly 100% cathedral ceilings. I have an active leak on one of the roof sections, and as such will be replacing the roof very shortly. The roof section is 6/12 pitch 22 feet wide and 28 feet high with two layers of asphalt shingles.

I would like to address some of the shortcomings of the existing roof system which are:

In General questions | Asked By Bernie Simon | Dec 31 11
3 Answers

Where can I find the "insect screen -full width" that is shown in detail 2-00004?

I am using the GBA wall section detail #2-00004. I have been looking online for the insect screen described in the detail. I envision it as something like a soft mesh that is 3/4 thick. Is there anything out there that is not too expensive? If so, who is making it?

In Green products and materials | Asked By Beth Robinson | Jan 6 12
5 Answers

How to build a movable passive solar heat sink?

My wife & I are remodeling a house to accomodate a 133 inch long dining table when fully expanded. Most of the time the table is closed to a 60 inch diameter. We will install a south facing window approx. 7 ft. long x 4 ft. high. Except for when the table is fully expanded (1% of the time), we could have a passive solar heat sink inside the room near the window, but need to move it to accommodate the table when fully expanded. Have been thinking of something water filled. We could install a faucet & drain in the room. A movable sink would also allow it to be unused during the summer.

In PassivHaus | Asked By Robert McDonald | May 24 09
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