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3 Answers

I've heard that some heat recovery ventilators produce ozone. Is that true, and if so how?

How can you know you are buying one that doesn't?

Asked By mark romwalter | Oct 8 17
1 Answer

What are my options for attaching and protecting foam insulation to exterior concrete basement walls?

I live in an area of frequent freeze/thaw. basement walls have foam insulation that has detached in some places, and has just generally degraded over the past 10-15 years.

Asked By user-6932004 | Oct 9 17
4 Answers

XPS on ridge beam

I insulated my basement walls with 2” XPS including cut and cobbling foam on to the ridge beam. The walls will be frammed and finished with wallboard. But do I need to also put drywall over the foam in the ridge beam to meet code?

Asked By adam stanton | Oct 7 17
4 Answers

SIP Wall to Gable Corner Question

I am curious to hear if how a design pro might approach a SIP Wall corner at the gable end of a house. I have 2 choices as to whether to run the wall panel long or the gable panel long. Just curious to hear what the advantages to each approach might be. I don't think either approach is structurally any different but there might be a difference that is not readily apparent to me. SIP mfg hasn't been too helpful in elucidating the pros and cons.

Thanks in advance for any thoughts.

Asked By John Brown | Oct 8 17
1 Answer

Leakage around windows and doors under housewrap

I am using osb sheathing as my primary air barrier and have caulked all panel edges before install along with taping seams with 8067 all weather flashing tape. Around the window and door openings I am also taping the osb to the framing. Tyvek will be installed and wrapped into window openings using the "inverted wineglass" technique. It seems, however, that unless I seal the tyvek to the rough opening framing, that air can leak through on the back side of the tyvek, even when the flanged window is installed, flashed, and caulked correctly.

Asked By Brett Greenburg | Oct 9 17
8 Answers

Will plumbing P-traps <i>under</i> rigid foam of a monolithic concrete pour risk freeze damage?

We are soon pouring a frost-protected shallow foundation here in MA. When the plumbing was installed, the ptraps for some of the fixtures (floor and shower drain) are below the place where the 6+ inches of EPS will sit Effectively, these traps will not be in the insulated envelope.

I am concerned about possible freeze issues in this scenario and need to decide whether I put a layer of foam on top of these traps (this would be to protect the house from the cold) OR leave off the foam over the ptraps (so that the warmth of the house will keep the ptraps warm enough in Winter).

Asked By Kenneth Gartner | Oct 7 17
12 Answers

Non-toxic ductwork

We are researching truly non-toxic ductwork for our all new electric heating/cooling... HVAC system. We are only finding the usual hardpipe which is known to be coated on inside with rust proofing, and the flex. The flex is found to be polyester and nylon in the interior with a wrap of insulation, probably but we've not been able to find that info yet, probably has fire retardant and formaldehyde, and who knows what. then the outer black plastic layer or silver whichever, silver would be best as all plastics outgas toxic fumes and when heated... even moreso.

Asked By Evan&Suzy | Oct 2 17
27 Answers

Conditioned crawl space

We recently had a contractor close up our crawl. they placed 10mil poly on the floor and spray foamed the walls. conditionied supply air is added to the space, and a return is vented outside. I do not seem to be noticing a difference though.

Asked By Shammah98 | Jun 9 17
5 Answers

Should I plan to better vent my roof later?

Hi GreenBuildingAdvisor,

I love your site. Lots of great information, and informative comments.

We just bought a 100 year old home. It is a story and a half. It has been through several renovations, many of which make me cringe. We should have bought a different house, but we were under pressure, and this will be our home for at least the next five years, if not the rest of my life (I'm 38).

Asked By Save a Penny | Oct 6 17
25 Answers

Another garage heating question


So I'm building my dream shop/garage, then I going to build my house.. So my wife is making sure I stay on budget.

Building is 64'x 40' x 14'

ICF frost walls that will be 4' below grade and 2' above grade then 12' of 2x6 walls on top for 14' ceiling.
Walls will be taped and sealed OSB best I can and have 3" (reused) Polyiso on exterior and filled with Roxul.
Attic spaced will have blown in cellulose, R???
Floor will have 4" foam under slab. If needed??

South facing side (64') will have 4 large 5' x 5' windows, casement style on half of 2 windows.

Asked By Dave B | Oct 4 17
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