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3 Answers

Saw your post referenced above and Peter Yost's "How to Insulate an Unvented Roof" last week.

In Energy efficiency and durability | Asked By C P | Nov 22 11
14 Answers

I've been trying to persuade my wife that we should install a mini-split, but the look of the indoor units is a non-starter for her. Personally I can overlook the issue because I like the energy savings, and I can get the thing for almost nothing by using utility rebates, but I do agree they look clunky and mechanical. A lot of people I talk to have the same feeling about them.

In Mechanicals | Asked By David Meiland | Nov 19 11
3 Answers

I recently installed a water heating element in my englander 3500 wood burner. Because the 80 gal storage tank and the wood burner are both in the basement and about 12 ft apart I opted to go with an active circulation system. Nothing fancy just a Grundfos pump with an aquastat. The w shaped Heating element is mounted horizontally in the firebox and the 1/2 copper plumbing runs across the ceiling between the tank and heater. To my surprise this system thermalsiphons pretty effectively. My question is how will this effect the performance.

In Mechanicals | Asked By Anthony Kramer | Nov 21 11
1 Answer

I am considering using stacks of polyisocyanurate to insulate a cathedral roof. Basically, two stacks of 2" foam between the rafters with a 3.5" ventilation chute above. Then another 2" layer below the rafters. I have read that polyisocyanurate foam can shrink as much as 1%, which I calculate to be about 1/2 for a 48" wide sheet. Will this cause issues later on? That is to say, by these calculations the foam will shrink up to 1/8" in between each rafter. Will the low expanding foam used to seal the between the rafter and foam expand to keep these gaps filled? Thanks in advance!

In GBA Pro help | Asked By David Baker | Nov 21 11
2 Answers

I am building a new home and would like to verify the correct placement of material. From the inside to outside: sheetrock > 2x6 > dense pack cellulose > OSB > foil faced polyiso foam > brick.
Covered back patio is same except hardie type siding instead of brick and polyiso with no foil face.

Would house wrap be redundant if placed over the OSB? Or is the polyiso foam overkill for this zone (which I think would then necessitate the house wrap)?

In General questions | Asked By Charles Tomlinson | Nov 18 11
3 Answers

I have a client that is questioning which is a better route...going with ZIP sheathing on the exterior and blown insulation for air tightness, or going with a standard 7/16" osb and open cell foam on the interior for air tightness. Exterior foam would be installed in either situation. Zone 6 for construction.
I was really not sure what is the best recommendation on air sealing. Cost wise, it appears it will be almost the same.

In Energy efficiency and durability | Asked By Jesse Lizer | Nov 16 11
11 Answers

I am trying to get my new built cottage down to .6ACH at 50 pascals. I had my third blower door test done today and initially received good news - we had achieved .6ACH. Then the tester ran the test again at ACH 150 and ran the results through some interpolation software. This test indicated an ACH 2.4 at 50 pascals. Thinking that there might be an error in the interpolation, he then used the duct blaster attached to a window and came up with an ACH 2.8 at 50 pascals.

In PassivHaus | Asked By Steve Snyder | Nov 18 11
16 Answers


How should I air seal and insulate a pine tongue-and-groove ceiling?

My house has a T&G ceiling. Over time the boards have contracted and caused gaps at the tongues and grooves. In a few areas where the ceiling has an angle change, I can see the insulation's kraft paper.

In Energy efficiency and durability | Asked By Walter L | Nov 13 11
10 Answers

I have a 1964 rambler home with a heated room under the garage. The garage slab is reinforced concrete in good condition. I'm planning to upgrade the home's insulation, and this seems like a major area needing attention. There is currently no insulation under the slab, and the room under the garage has a low ceiling (approx 7 ft). The garage has an internal floor drain and is heated, but we keep the temp set just above freezing. The most obvious solution would be to add foam insulation to the underside of the slab, but would this cause problems with condensation?

In Energy efficiency and durability | Asked By Jody Keppers | Nov 16 11

The designers at my firm have enjoyed using Tectum roof deck systems:


We are trying to avoid using XPS because of blowing agent issues, so we were encouraged to find out that Tectum offers an EPS option. Ideally though, they would offer a polyiso option. Since they don't, do any of you know of a similar product out there that offers polyiso instead of EPS or XPS?


In Green products and materials | Asked By Heather Gayle Holdridge | Nov 17 11
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