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!


5 Answers

Insulate rim joist with rigid foam: exposed concrete?

I'm trying to understand the different in recommendation in this FineHomebuilding article:

http://www.finehomebuilding.com/design/departments/energy-smart-details/...

If using spray foam it states "For good thermal performance, the foam should cover all of the exposed concrete at the top of the wall." and the picture shows the same.

On the section above for using foam board, it does not show the top of the concrete being insulated.

In Energy efficiency and durability | Asked By Jeremy M | Feb 22 16
4 Answers

Basement Insulation

Hello. i have a basement in zone 5B. we are getting ready to finish it and I have a couple questions.
Can i use 1/2" xps against the interior foundation, then frame up to that and use mineral wool batts in the stud wall to get to the reqd R value?
---the rim joists would also have xps and sealed with great stuff.
---wall seams will be taped and the bottom sealed with great stuff.

Should radon mitigation be done before or after insulating the foundation?

In Green building techniques | Asked By jaems sweepstakes | Feb 23 16
5 Answers

Is insulated vinyl siding worth the cost and is it effective? I am on the coast of Maryland.

Vinyl siding is inherently ventilated typically so it seems that any insulating value would be washed out. If that weren't an issue, isn't the relatively thin insulation enough to cause vapor drive issues in the winter? Minimum exterior foam thickness for my climate is 1" but 1.5" would be safer. We usually opt for 2".

In Energy efficiency and durability | Asked By Mike Labesky | Feb 22 16
17 Answers

Insulating cold bedroom not in building envelope

My wife and I recently bought a brick, 1925 Victorian twin in Philadelphia. It has 3 floors + attic, but the 3rd floor and attic spaces do not extend over the top of the bedroom at the back of the house. We are planning to use this room as our main bedroom but it is significantly colder than the rest of the house.

I've been reading as much as I canon GBA and many other site and online videos, but I am at a loss to know how to improve the comfort level in the room.

In Energy efficiency and durability | Asked By Chris Trollen | Feb 22 16
5 Answers

Where to put membrane on unvented metal/polyiso roof

Hey folks,

I'm renovating an old house in Tucson, Arizona and I'm just about to put a new roof on. The previous owners of the house knocked out the old drop ceiling, closed off the vents, and stuffed a bit of fiberglass between the roof and a tongue-and-groove ceiling. It's a very low-sloped roof, so they created a glorious 6" cathedral ceiling and a mold problem. Hopefully I can do a bit better.

I've been reading lots of articles on GBA and I've got a plan, but I want to put it up for scrutiny to make sure I don't overlook anything obvious. Can you give me a quick stupid-check?

In General questions | Asked By Aengus Anderson | Feb 22 16
1 Answer

Safety of new baseboard heaters?

I'm really torn on what we should do for baseboard heaters. Dimplex and Likewise makes compact (inexpensive) baseboard heaters... 40" long for 1500W. Everything else is about 65"(ish) for the same wattage. But I'm concerned about the Likewise and Dimplex because the tops are open with a grate thing. Someone told me that they're fire hazards because the tops are open. So then I thought about getting the "old style" with the panel at the top (where it's open more in the middle).

In Energy efficiency and durability | Asked By Sarah Poulin | Feb 23 16
4 Answers

Faced or unfaced?

I have talked to you before. Hopefully you can help me once more. I'm in Zone 2a. The building is metal. It's going to be a/c only.

I wanted to foam it -- but $$$$, so I'm going to put a vapor barrier in the cavity, an air space will be maintained at the metal, then put a Johns Manville wool/fiberglass batt in the wall, then drywall and paint.

In Energy efficiency and durability | Asked By Bill Metzger | Feb 22 16
2 Answers

Consultant needed

My wife and I are looking to build a new home in St. Louis, MO. We would like to find an architect who can help us build a very green home.

I have a good architect in mind, however green is not their focus. We were thinking it would be useful to work with a consultant who could guide us and work with the architect to design an extremely efficient home. We are not necessarily looking to be net zero, but we would like a home that is built to the very best efficiency standards available.

In Project management | Asked By Peter Perkins | Feb 22 16
12 Answers

What is the best way to install floating laminate over basement slab?

We are installing laminate flooring (and one room of tile) over an unsealed basement slab. The basement has exterior waterproofing, drain tiles, and sump pump. We live in the midwest - so lots of temp changes and humidity. What is the best way to install floating laminate flooring over basement slab? We do not have rigid foam installed under the slab unfortunately, so I am thinking we do need some under the flooring. I want to do everything we can to prevent condensation and moisture/mold/mildew problems. The basement is a walkout on the entire 4th wall. Thank you!!!!

In Green building techniques | Asked By Carolyn Farrow | Feb 13 16
13 Answers

Basement insulation / wall framing with limited space

Hi. I'm working on a basement in a 1960s ranch in Minneapolis, all below grade, with a concrete block foundation. I've read pretty much all of the articles here about basement insulation, and I was set on doing the following: 2 inches of XPS glued to the block, then a 2x4 framed wall, and then either XPS or spray foam in the stud bays. HOWEVER...

In General questions | Asked By Jay | Jan 20 16
Register for a free account and join the conversation


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