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!

7 Answers

Who makes a decent fiberglass entry door?

I've been looking at Therma Tru, Pella, and Jeld Wen. Ideally, I'd like an Energy Star door that seals well and offers decent quality. The contemporary style of our home means the door will be mostly glass, so that part is as important as the frame.

Thanks in advance for your suggestions.

In Green products and materials | Asked By Steven Knapp | Aug 25 13
2 Answers

Should I call for rigid mineral wool sheathing to be installed in two layers?

I'm planning to use rigid mineral wool sheathing on a retrofit project. In the past when I've done this with XPS or polyiso rigid foam sheathing, I've called for 2 layers of foam, with staggered seams, presumably because rigid foam shrinks and installing in 2 layers reduces the likelihood of "cold lines" in the continuous insulation layer. Mineral wood doesn't appear to be a product that shrinks and the photos I see suggest that the product can be joined at each edge quite tightly.

In Energy efficiency and durability | Asked By Rachel Wagner | Sep 26 13
2 Answers

Building a better system to build a better house

I’ve been doing a lot of reading on this site with the blogs and the Q&A section. I’ve learned a pretty fair amount about Passivhaus , Net Zero and Green Buliding . I’ve come to some conclusions that I think may be valid, but wonder if there should be more.

In General questions | Asked By Dan N | Sep 26 13
5 Answers

Installing vertical cedar siding over external foam and housewrap


In Energy efficiency and durability | Asked By Chris O Brien | Sep 25 13
3 Answers

Rigid foam over kneewall studs to eliminate thermal bridging?

Hello! I've got a 1926 bungalow in Portland, OR (zone 4C). The attic was finished in the 50's, and is terribly leaky and not insulated. The previous owners left behind a boatload of fiberglass batts, unwrapped, with kraft paper backing. I was hoping to use them to insulate the kneewall, after air-sealing the gaps with some caulk.

However, since the joist bays are somewhat shallow (I believe ~3.5"), I was hoping to cover the outside of the studs with rigid foam insulation as well (XPS or ISO) to prevent thermal bridging, secured in place with a polyurethane expanding foam.

In Energy efficiency and durability | Asked By Richard Smaldone | Sep 25 13
3 Answers

Final insulation questions for wall and attic

Ok...I'm getting ready to finish up insulating my interior walls and my attic.


In Energy efficiency and durability | Asked By Geoffrey Cook | Sep 26 13
2 Answers

System efficiency: forced air furnace vs. water heater/air handler

Where would I go to predict the relative efficiency of these setups:
1) An efficient forced air furnace, plus separate efficient water heater.
2) The same class of water heater, but with a water-to-air air handler instead of the furnace.
(In this case for a 1500sf insulated one bath single family home in a mild climate, which has no existing furnace)

In Energy efficiency and durability | Asked By Bryce Nesbitt | Sep 26 13
1 Answer

How to install a mail slot in brick wall thru garage drywall

How do I install a mail slot in an exterior brick wall thru garage drywall? What is the distance between the garage wall beams? Thank you.

In General questions | Asked By Sharon Yanish | Sep 26 13
1 Answer

Pre-existing unvented cathedral ceiling-- will there be problems?

My client has a house built in the 1970s with cathedral ceilings, a shallow (2 in 12) roof, 2x12 rafters, and T&G pine ceiling. The ceiling was insulated (looks like R-38 faced batts), but there is neither ridge nor soffet venting. The owner had a membrane roof put on about 2 years ago and now wants to remodel. I am concerned about an unvented roof with a relatively "leaky" ceiling-- won't there be issues with moist air getting into rafter space and condensing on the underside of the roof deck?

In GBA Pro help | Asked By cynthia sharon | Sep 25 13
0 Answers

Dirty Sock Syndrome

I have been asked to come out and look at a home with a dirty sock smell coming from the HVAC. This is a home built in 2012. It is a ranch home with a finished basement. Supposedly it is a tight and energy efficient home that includes mechanical ventilation. The home does have a whole house dehumidifier that has been shut off and the smell still persists.

In General questions | Asked By Robert Hronek | Sep 25 13
Register for a free account and join the conversation

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