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Much of the value of this site is the pooled experience of members and their willingness to share it. One way is by using the comment boxes that follow every post. This page offers a Community area formatted for Questions & Answers. Please notice on the right that we've divided the Q&A forum into topics to make it easier to find your area of interest.

Anyone may ask a question--about anything within the realm of residential green building--and anyone may answer. Sometimes one of our 15 Advisors may chime in; in other cases, you'll get the wisdom of some of our members who have experience with the detail, material, code, etc. that prompted the question. We encourage everyone to give us the benefit of both their questions and answers. The usual rules of courtesy apply.

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93 Answers
Serious Windows vs. Thermotech, Fibertec, Inline, Accurate Dorwin

Does anyone have experience with Serious Windows or Canadian fiberglass windows? I'm having a difficult time finding high SHGC windows (with a U-value less than or equal to 0.30) for my passive solar home that are affordable. Looks like the fiberglass windows can give me the performance I'm looking for, but I can't find any local installations to inspect the quality of manufacture.

In Energy efficiency and durability | Asked By Claire Anderson | Oct 1 09
12 Answers
Do you need to air seal ICFs?

We are planning a house using ICFs. We are building to the Passive House standard of 0.6 ACH at 50 Pascal. ICF manufacturers have told me that we don't need to air seal. I understand that ICFs with the concrete will be pretty air-tight but I still see the joints where the ICFs meet as potential weak spots. Will I need to air seal them and how would you do it?

Thanks

In Green products and materials | Asked By Roger Lin | Sep 1 10
27 Answers
HRV or ERV in cold climate?

I'm building a well insulated house (R-40 walls and R-60 roof) in a 9500 heating degree day climate (Upper Michigan) and will not have air conditioning. Most sources seem to suggest an HRV in this situation but I have had several people recommend an ERV as the better choice. What would I gain with an ERV in my situation, I thought ERVs were for air conditioning climates?

In Mechanicals | Asked By Donald Lintner | Aug 11 09
7 Answers
Flash and Batt and moisture issues...

I am 2/3 way through a major remodeling project and insulation time is fast approaching. I am looking hard at sprayed foam insulation and have prices closed cell. I Iive in the outskits of D.C. so the climate is zone 4 with 5 not too far off and humid.

I have four areas to insulate:
1. First floor -existing Brick outside wall, airspace, 4" block wall and treated 2x2 lathing. Proposed 1 1/2 pink foam board glued to block wall between lathing and then drywall over it. Q - is this a good plan and do I need to worry about a vapor barrier?

In Green building techniques | Asked By Scott Miller | Sep 1 10
3 Answers
Helix as rebar/mesh replacement

I am considering trying out adding Helix (steel fiber) into concrete and do away with rebars.

Any experience with this positive or negative in slab applications and ICF wall applications?

Thanks in advance.

In Green products and materials | Asked By Roger Lin | Aug 27 10
1 Answer
Injected foam insulation

I am trying to get some ball park about injectable core foam for hollow concrete blocks.

I have an existing home in South Fl houses faces east and west. I am considering having the walls filled with inject able core foam. The only insulation that I think is in the walls is the brown paper with foil on back. The house is CBS built in 2001.

In Energy efficiency and durability | Asked By Roberta Atkins | Sep 1 10
10 Answers
Challenging Floor Details

I've seen a lot of discussion about wall and roof details with respect to air, vapor, and thermal transmission. What I haven't seen is discussion of the flooring and how this contributes to thermal and moisture problems. And I have a quite challenging situation that has me a bit stumped.

In Green building techniques | Asked By corn walker | Aug 30 10
9 Answers
Can I get away with radiant floor heat, some ducted dehumidification for summertime, and spot ERVS in a large-ish new home in Virginia?

I live in the foothills of the Appalachians.

In Mechanicals | Asked By Neal King | Sep 1 10
39 Answers
Ducting in slabs & passive solar

I'm looking for research that examines the effects of using ducting in concrete slabs to circulate heat. Specifically, I'm interested if there is any added efficiency in passive solar applications where air is circulated through the slab. My impression is that this technique opens you up to a lot of potential moisture/mould scenarios. Does anyone know of any research that looks at the implications of this technique?
Thanks,
Jay

In Green building techniques | Asked By Jay | Jul 19 10
5 Answers
Adding insulation from the exterior

Climate Zone 5 / Western Massachusetts

I am working on a project that involves a cape style house with existing 2 x 6 rafters spaced at 24" o.c. Currently, the 48" high knee walls and unused portion of the floor from knee wall to eave are insulated with fiberglass batts. The roof slope to the peak has been dense packed with cellulose insulation - no venting - and 2" of XPS rigid insulation and strapping applied prior to drywall.

The house will need a new asphalt shingle roof next year.

In Green building techniques | Asked By Jon Wyman | Aug 25 10