Community: Green products and materials

Q & A Instructions

[Click map to enlarge]

The web site has a wealth of articles on a wide variety of construction topics. Before posting your question, you may want to check out the articles on this page: How To Do Everything. You just might discover an article there that provides the information you seek.

Please register for a free account or sign in to ask and answer green building questions.

If you want to post a question, the usual rules of courtesy apply:
1. Be nice.
2. If you can't be nice, be polite.
3. If you can't be nice or polite — well, please be brief.

To attach a photo or illustration: Under the box labeled “More explanation,” look for the words “File attachments.” Click that, and you should be able to attach a photo.

Thanks for joining the conversation!

1 Answer

Are solar panels today carbon footprint break-even during (and after) lifetime?

I know this is ever changing, and big effort is being made to find new ways to produce PV panels from cheaper/more environmentally friendly materials, but if I were to buy PV panels today, will they ever reach carbon footprint break-even point, when we take into account their production AND waste management?

On some soruces, I've found that getting rid of these panels is a big problem, because of the toxic materials used. How big a problem is this?

Asked By Davor Radman | Apr 19 18
11 Answers

Comfort Board 80 vs 110 - density worth extra cost?

For our upcoming house build using 4" of rigid mineral wool we have been quoted for both Roxul comfort board 80 and 110. Over the top of this we will install 2x4 furring and cedar siding.

The 110 has a compressive strength of 1120 PSF at 10% deflection, the 80 is only 439 PSF at 10%, using the 110 will simplify the installation of furring as it will compress less, but I don’t know that the furring installation sub would price their install any differently between the two products. (Furring install not by insulation contractor).

Asked By Chris Armstrong | Nov 16 16
28 Answers

Are low-e windows dangerous?

I've read a couple of articles that suggest low-e windows can cause fires. It sounds like the low-e coating (or a film, the articles weren't clear) is capable of reflecting and focusing sunlight in a way that can cause materials outside the house to combust. Does anyone have an explanation for what is going on with these windows?

Asked By Steve Knapp CZ 3A Georgia | Apr 1 18
14 Answers

Dense-packed dry cellulose: any downsides?

I've been going over insulation techniques to use on a new home. Every insulation contractor that we've talked to has a different system. One in particular that is being pushed is dense pack dry cellulose. I have personally witnessed wet cellulose settling in our own home, however based on everything I have read about and heard about dense pack is that it will not settle and that our current home's insulation was not installed properly. I know that cellulose is somewhat springy so I understand the theory is it will hold true in the wall for hopefully many many years.

Asked By Css1813 | Apr 16 18
3 Answers

Performance of polyiso exterior foam at cold temperatures

I've been meaning to post this ever since you helped me out with this question:

One of the last comments by Dana was that in my analysis I should de-rate the foam (especially if it is reclaimed)

"But for unknown goods don't count on it for being better than mid-5s from a design point of view."

Asked By Steve Mackay | Apr 17 18
16 Answers

Recommended European Tilt Turn Options with Thinnest Site Line

We had originally specced our project with Yaro UPVC but were considering options with smaller frames and similar high performance windows. One option is the Tanner Vitra.

The Vitra frame is 3.3” while the Yaro frame (currently specified product) is 4.6”. A difference of 1.3” in frame width. This equates to 2.6” more glass in both height and width (2 x frame dim.). This narrower frame will significantly change the feeling of openness one gets from a window of equal size. Of course the Vitra is more expensive and we're estimating about 45% more. Performance-wise they're very similar.

Asked By J M | Apr 7 18
12 Answers

Sliding Glass Patio Door - Leakage Rate?

Climate zone 6A and doing a pretty good home with a target leakage rate of less than 1.5ACH50. I'm just starting to look at windows so I'm not fully up on the technical specifications yet.

Asked By Steve Mackay | Apr 13 18
5 Answers

Least evil of my wall system options

Border of Zone 4/5. I've read much of the material on this website about wall systems. While I have my desires for advanced framing techniques, including 2x6 24OC and thick foamboard outside insulation, these things aren't a realistic option with builders/subs in my area undergoing a building boom.

The path of least resistance is 2x4 or 2x6 16OC. The only other builder/framer reluctant possibility is Zip-R with built-in polyiso. My city uses the 2012 IECC, but has amended the walls from R20 or R13+5 down to R13. Yes, you read right, here in 2018, the Zone 4/5 wall code is R13.

Asked By Bruce Davis | Apr 11 18
8 Answers

Foil Faced Polyiso & DrainWarp for OSB drying

A week or two ago there was discussion about vapor permeability of foil faced polyiso exterior foam and the effect it has on drying of the sheathing.

I came across this Tyvek Drainwrap which sounds like it is similar to regular building wrap except it provides a drainage route between the sheathing and exterior foam. It seems like it would also be a way for the sheathing to dry to both the inside and outside.

Does anybody know of its effectiveness or is it just marketing hype to sell more expensive building wrap?

Asked By Steve Mackay | Apr 6 18
25 Answers

Starting point for affordable triple-glazed windows?

Hi guys, we are building in the White Mountains in New Hampshire. 1250 square-foot oneday retirment house with a small loft. We haven't solidified any details yet but are shooting for a pretty good house.

Asked By John Williams | Mar 18 17
Register for a free account and join the conversation

Get a free account and join the conversation!
Become a GBA PRO!