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8 Answers

Vapor Barrier to Prevent off gassing of CCA treated wood and OSB ?

I am in the middle of house building for a passive solar designed house in a mild marine Climate in southern Chile ( similar to Portland Oregon) where likely using a vapor barrier would not cause problems from what I understand.

The house frame upper and lower floor was built with OSB which I understand contains formaldehyde and CCA pressure treated wood. These are common construction methods where I live.

In this case might someone recommend a vapor barrier to prevent off-gassing from the CCA wood and formaldehyde in the OSB ?

In General questions | Asked By marion marshall | Jan 19 13
4 Answers

Wall assembly strategy using Dow structural insulated sheathing

I live in MD, climate zone 4 and want to use the DOW SIS 1" with blown in high density insulation. I can use a 2x4 wall to achieve R20 in the wall. Please help me settle a disagreement with my architect. He is concerned with using the DOW SIS product because the product has such a low perm rating that it will act as a vapor barrier and the wall won't dry to the exterior. He has traditionally used an interior poly so the wall needs to dry to the exterior. I say leave off the interior poly so the wall dries to interior.

In Energy efficiency and durability | Asked By Ryan Sober | Jan 19 13
1 Answer

Basement insulation retrofit - walls versus floors

Here and elsewhere its commonly advised to insulate basement walls with foam panels and permeable walls. My understanding is that this allows water vapor to diffuse through insulation and wall assembly without the occurrence of condensation and related problems. I've not seen where installation of a vapor barrier between wall and foam board, whether plastic sheeting or waterproofing agents is recommended, at least not unless liquid water was entering through the walls.

In Green building techniques | Asked By Andrew Alden | Jan 19 13
26 Answers

What should I do about improper installation of an air exchanger?

A year and 4 days ago, we moved into a brand new house. Installed already was a Venmar AVS air exchanger. Immediately we found that the house always felt cold. Being a newly constructed house, and our first winter in the house, we thought that we just needed to 'let the house warm up' and remove the humidity. We left the air exchanger on the setting that was recommended by the installer. We found that the house, and basement especially always felt cold. The windows constantly have condensation on them, and it is difficult to breathe.

In General questions | Asked By C Wat | Jan 17 13
4 Answers

Achieving net zero in a row home with one minisplit per floor?

I would like some opinions from all you smart people.

I have read many of the articles/posts on this site about a one head per floor minisplit approach for a net zero buildings. I do gut renovations of row homes in DC and have LEED Platinum certification on some, but have not achieved net zero. But I really want to!

Since these are existing ~100 year young brick rowhomes, mostly with attached frame porches, we cannot achieve a passive house tightness with our current construction techniques. We achieve in the neighborhood of 3.5 ACH50.

In Mechanicals | Asked By Tanya Topolewski | Jan 18 13
6 Answers

Recessed IC can lights in unventilated cathedral ceiling.

I'm having a log home built wth cathedral ceilings. I plan to have 1 1/2 to 2 inch closed cell polyurethane sprayed onto the interior side of the roof sheathing with blown in insulation filling the balance of the twelve inch rafter (I beam style of rafter) cavity. This wll be an unventilated roof. Tongue and groove will be used on the ceiling surface. I understand the spray foam will act as an air barrier, and the tongue and groove is very air permeable.

In GBA Pro help | Asked By Rick Schneider | Nov 7 12
3 Answers

Cathedral ceiling, adding insulation....

I have posted here before about retrofitting my house with spray foam and turning it into an unvented attic. I have since realized that this will be a huge waste of money since my home is already set up and insulated with batt insulation. So, I would like to add to or correct what I have and go with it. Ive talked to a few pros and the only ones suggesting I do spray foam are...well, the spray foam companies. Everyone else actually suggests I add to what I have or don't add anything.

In Energy efficiency and durability | Asked By Jason Duke | Jan 18 13
7 Answers

What material should I use to fill the footprint of my new home ?

As seen in the attached photograph the new home (near Brockville, Ontario, Canada) is being built 100% on granite bedrock. The site slopes to the west . That is the right-hand side of the photograph. There are two drains (4" diameter) located on the footings on the west side.

The home will have a 4" concrete slab on 2" of rigid insulation (taped). This will sit on the fill. At the east and north sides of the homes, the fill will be perhaps 1 foot thick. At the west side, the fill will be perhaps 4 feet thick.

In General questions | Asked By Wilder Boucaud | Nov 2 12
11 Answers

Will I have humidity issues with a closed cell retro?

I am considering removing all of my batting insulation and having my attic spray foamed. My second story is unfinished, meaning it has no drywall yet. So, that is a plus for this installation. My question is, if I have 6" of open cell foam put at the roof line and SEAL the attic, will I end up with moisture issues in the attic??? I live near Houston, so its humid. The installers I have spoken with insist that there is enough air transfer through drywall and the relatively few can lights to alleviate the potential issue. Also, my AC probably has a little leakage into the attic.

In Green building techniques | Asked By Jason Duke | Aug 13 12
38 Answers

Opinions on radiant ceiling heat?

I checked out a building yesterday that had heating mats like this one installed in four areas. Obviously it's electrical resistance heat, and there's an attic above so there's doubtless some loss into the attic, but these definitely make you feel warm, because your head is so close to the heat source. There was 1260 watts of heating installed in this area, along with 576 watts of fluorescent tubes. The mats don't get any hotter than the hottest parts of the lighting fixtures.

Any comments on this type of heating?

In General questions | Asked By David Meiland | Jan 31 12
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