Q&A: A Forum for Green Building Experts and Beginners

Q & A Instructions

[Click map to enlarge]

The GBAGreenBuildingAdvisor.com 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!

0 Answers

Should I tape vapor barrier to foam board?

Good day. I'm remodeling a tub surround on an exterior wall and want to air seal properly. Should I tape closed the "pockets" of black plastic, which I believe are the laps of vapor barrier where they come through the foam board and then down on the outside?

Tim in TX

Asked By TX Tim | May 28 17
0 Answers

What is the best flooring for pier and beam with plywood subfloor?

I have a house on pier and beam with a plywood subfloor. The cavities between floor joists are filled with about 4-5 inches of open cell foam. I live about 50 miles southeast of San Antonio, TX. I need suggestions for flooring that will allow inward drying of the subfloor. Thank you in advance for you help/suggestions.

Asked By Brian Hons | May 28 17
5 Answers

Do Light-colored 'cool' Roofs add to winter heat load?

Has anyone done a calc to compare the summer savings from a cool roof versus a possible greater heat load in winter than that where the roof is dark-colored?

Asked By David Goldman | May 27 17
0 Answers

Martin - Knee wall and foam

Martin, I recently asked question about air washing insulation in knee wall applications and you suggested foam backing and said it would not create a double moisture barrier. (can't seem to add a follow-up question to the thread) I have since read several other posts on this site which suggested that foil faced foam in this application would create a moisture trap. Please clarify.

Asked By Bob Brown | May 28 17
6 Answers

How do I get Comcast through my envelope prior to blower door test?

In anticipation of a blower door test, water, sewer, electricity, and gas were run to house with one phone call each. Can anyone suggest a way to convince Comcast to provide a stub-out to new construction with studs not yet covered?

Three weeks and half a dozen phone calls (each one requiring a half hour just to get to someone who could look at the job ticket) I usually get: “T.V. has to be ready to hook up before we can install service.” Why, I ask, can you not bring the cable to a utility box and test the signal there? Yesterday I learned this:

Asked By David McNeely | May 27 17
7 Answers

Understanding HRV Energy Use Calculations

I am trying to understand the last column on the below sheet. I can see that the "last but one" column value is arrived at by subtracting the "Total Annual Energy Use (KWh @ COP 1.0)" from "Recovered Heating Energy (KWh/yr)". But I am trying to figure out how the last column values are being arrived at and also what the last 2 columns mean in layman terms. Thanks.


Asked By Venkat Y | May 27 17
3 Answers

Hot dormer: radiant barrier time?

I have read Martin's "Radiant Barriers: A Solution in Search of a Problem"

I have an existing house, about two years old. The second story is made up of two dormers, a bathroom, a "bonus room," and some "usable" attic space (outside building envelope).

The second story gets much hotter than downstairs (8-10 degrees in hot days). I'm interested in whether there's anything we can do to address that, short of cranking the hvac.

Asked By Maurice A | May 27 17
0 Answers

Wide door for workshop built to passive house standards

I am looking for an affordable wide door for a workshop that meets passive house standards.

I want to preserve as much wall space as possible.

I am looking for at least 6 to 8 feet of opening. With this being a workshop, it doesn't need to be a work of art, just functional.

I had looked at the Zola breezeway panel door. That is not available in their lower priced uPVC lines.



Asked By Andrew Sanderson | May 28 17
0 Answers

what is the datasheet of the ARCO panel which was in the picture?

the non silicon panels that are more than 30 year old.

Asked By shrik kader | May 28 17
4 Answers

Adding an addition after AirKrete and polyiso - now what?

1960's ranch near Rochester, NY

A couple of years ago, the home was resided with vinyl. I took this opportunity to have the home wrapped in Tyvek and covered in 1.5" reclaimed polyiso with black kraft facing. The walls, which had minimal fiberglass insulation, were filled with AirKrete.

Overall this has performed well, the home is quiet and the walls are warm in winter and comfortable - despite problems with the local contractor.

Now I am looking to add an addition, 10x20. The addition will bump out one wall and require part of another to be modified.

Asked By J Heckmann | May 27 17
Register for a free account and join the conversation

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