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12 Answers

Should I use closed-cell foam to replace rodent-ruined insulation?

20-year old house has uninsulated basement (both a crawl space and a concrete part) and attic.

There is insulation in the ceiling of the basement of the type that you roll out, as well as the floor of the attic.

The insulation has been ruined by rodents.

It seemed that replacing the ruined insulation with 3" of closed cell foam that would be clean and rodent-resistant would be an easy choice. But I want to make sure there are no serious drawbacks.

-Besides price, are there any drawbacks to properly installed closed cell foam?

In Energy efficiency and durability | Asked By Moya Mim | Oct 15 12
4 Answers

Is closed-cell spray foam fire resistant or does it spread fire?

I was surprised to hear that closed cell spray foam if installed in basement has to either have (i) special paint coating to slow down the spread of fire or (ii) sheet rock over it.

Is this a true? Is this an advantage of open cell spray foam, in that it is much more fire resistant?

In Energy efficiency and durability | Asked By Moya Mim | Oct 18 12
3 Answers

IBC Airtightness conversion

How do you convert cfm/sq. ft. @ 75 Pa to ACH 50?


In Building Code Questions | Asked By Roger Lin | Oct 17 12
3 Answers

Insulating a walkout basement in Alaska

I have a 6 year old home with a partially finished basement. I have been in the home a year and would like the basement to feel warmer. The house is partially underground as we are on a sloped lot. The walls are block underground and wood framed above, with a concrete floor that I think is uninsulated.
The walls in the unfinished space have fiberglass batts and vapor barrier. Electrical is done what would be a good way to tackle this? Leave walls in place and foam or use thin sheets of foam behind walls? The walls are built about an inch from the block walls.

Thank you

In General questions | Asked By Kelli Cornwell | Oct 17 12
9 Answers

How to size a woodstove for a superinsulated house?

Seems that sizing heatingunits in a superinsulated house is a real challenge! The 3000 sqf house I have built just outside Ottawa, Ontario, Canada, has R54 walls, R80 attic insulation, R25 slab insulation and triple-pane fibreglass windows. It is situated due south, and has a passive solar glazing area to floor area ratio of 11.5%. The heat load calculation determined a 33,000 btu heat load.

In Mechanicals | Asked By John Scime | Oct 16 12
3 Answers

Air quality issues from air sealing attic?

If I air seal the ceiling plane of a client's attic using canned spray foam, caulk, rigid foam, etc., what is the chance I'll cause an indoor air quality issue because the house no longer has sufficient ventilation?

Most of the homes I work with are at least 15 years old. I realize in an ideal world you would do before/after blower-door testing and all the combustion appliances would have dedicated air intakes but that just isn't a financial possibility for my clients.

In Energy efficiency and durability | Asked By Randy Ransom | Oct 17 12
4 Answers

How to insulate prefab chimney interior wall

I have had a roof leak around the chimney masonry which was apparently "fixed" by the previous owner while continuing to leak small amount of water into the wall by the side of the fireplace. This wall is now open to allow for replacement of the rotted studs, and I'd like to improve on the original insulation from the inside. On the other side of the wall is the open prefab chimney cavity - apparently just one layer of brick lined on the interior with some plywood and fiberboard.

In Energy efficiency and durability | Asked By Laura Mitrescu | Oct 15 12
35 Answers

Will mold grow between foam panels in the wall?

Hi, I am planning a new house in Wisconsin with 2" x 12" wood framing. The wall will be: drywall, 6" thick faced fiberglass batt, 3 foam panels 2" thick each, plywood sheating, house wrap, tar paper, corrugated stucco wrap, stucco. I am wondering if there is a problem with condensation between the foam panels causing mold. I am planning on making the drywall and plywood be air barriers. Also, instead of 2" x 12" wall studs, I am planning on two 2" x 4" studs with a 4" space between them for insulation.

In Energy efficiency and durability | Asked By Dennis Vogt | Oct 8 12
6 Answers

What would be the best low VOC product to seal cedar to prevent its natural VOC emissions?

My wife is very sensitive to VOC's. We have an expensive 3 year old oak bedroom dresser and two matching nightstands with a total of 20 drawers that have dovetailed joints and cedar sides and backs. The cedar in the drawers is causing my wife headaches, and we will have to sell the furniture at quite a financial sacrifice unless I can find a low VOC coating of some kind, primer, polyurethane, whatever, to seal the cedar well enough to prevent its natural emissions. Any ideas as to what would work would be very appreciated.

In Green products and materials | Asked By James Day | Oct 14 12
3 Answers

Top plate sealing? (ADA)

We plan on using Conservation Technology EPDM gaskets between the slab and (bottom) sill plate. And then some form of gaskets to create the airtight drywall approach (either the ones from conservation technolgy or Denarco).

What I am still a little unclear about is what if any seal is needed at the top plate(s)? The house will have a double 2x6 top plate. I have looked at a few different diagrams about ADA and weather sealing and for some reason I am still confused.

I found this diagram from an older post by John Brooks (hope you don't mind me using it):

In Energy efficiency and durability | Asked By Jack G. | Oct 17 12
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