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5 Answers

Caulking with closed cell insulation

I am building a new home with R30 and R 50 walls and ceilings. We will have 3" of closed cell in the basement walls.
What are best management practices for caulking?
Thanks in advance.
Peter Whitman

In Green building techniques | Asked By Peter Whitman | Jul 15 15
13 Answers

Spray foam on top of upstairs ceiling?

Getting down to the details now on my design (Upstate NY Zone 5 near Zone 6). I plan a cold attic with vented soffits, baffles protecting the upwards airflow, and no ceiling intrusions like wiring, lights, outlets ducts or holes/hatches for access from inside. My plan is to build a fake ceiling and soffited sheet rock below the original ceiling WITHIN the envelope, in which to run my ducts and put a few ceiling lights or fans up there. I plan on building a door on the gable peak large enough to get into the attic by removing some screws that will hold it in place.

In Green building techniques | Asked By Joe Suhrada | Jul 14 15
1 Answer

Need to know how good Prodex insulation is for under metal roofing?

Thinking about using Prodex insulation under metal roofing need advice.

In Green products and materials | Asked By Troy Tubbs | Jul 16 15
1 Answer

Can spray foam help?

My home originally had an open front porch which, at one point, was enclosed. I recently had the enclosure torn off and reconstructed so that the area would serve as an addition to the home's front room. The new "addition" sits atop a "coal bin." Would spray foam help insulate the front room from any moisture and drafts from the coal bin?

In General questions | Asked By Kevin McArdle | Jul 16 15
3 Answers

Spray foam under outdoor space. Good or bad idea?

I've got a outdoor patio, about 300sq/ft. Its got a hallway on one side, and covered patio on the other.

The hallway already has sprayfoam on the underside of the roof deck, in the wall cavity and under the slab. Its represented by area in blue (see attached).

The covered patio area currently has nothing for insulation in it. I was planning on doing T&G fir on the underside of the covered patio under the vault.

I'm wondering if there is any benefit to putting spray foam or any insulation under the covered patio even though the area is not heated?

In General questions | Asked By Mark Helmrich | Jul 15 15
1 Answer

Is a heat-pump water heater in Zone 7 worth it?

I'm currently designing a highly efficient 2 bedroom 1080 sqft house. Right now I am wondering if a heat pump water heater would pay itself off before it needs to be replaced. Also, the mechanical room would only be 3'6" x 7'6", not big enough size for manufactures recommendations of 10'x10'x10'

My question is how could I run the numbers to see if buying one is a good investment?

In Energy efficiency and durability | Asked By Matt Berger | Jul 15 15
4 Answers

Is humidity above 60% above grade as much a mold problem as basements?

For houses without A/C in the summer in humid areas why is not mold a big problem?

In Energy efficiency and durability | Asked By Alan B | Jul 15 15
2 Answers

How much is R-value reduced by screws/nails and other fasteners?

Plywood/OSB is installed with nails/screws, the same with foam board, siding, studs and many other components, has anyone done the math to figure out how much they reduce the insulating value (since they are usually metal).

I'd like to hope its almost zero, but data/calculations may show an appreciable effect?

In Energy efficiency and durability | Asked By Alan B | Jul 15 15
2 Answers

Is it cool to use butyl and acrylic tape together?

Have some tyvek flex tape, is there some chemical weirdness that might occur with say 3m all weather?

In General questions | Asked By kevin freeman | Jul 14 15
13 Answers

Should I correct the ductwork or the un-insulated walls or both?


We live in Hudson, Quebec between Montreal & Ottawa. My plan is to insulate walls of 2 rooms, from the inside, using 2" EPS Type I insulation, covered with a reflective vapor barrier directly on the existing drywall and 1" furring strips and 1/2 drywall. These rooms have 2 “exterior walls” each and tend to be more humid and cold than the other rooms.

In Energy efficiency and durability | Asked By domenic montagano | Jul 10 15
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