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!

2 Answers

Attic insulation need a solution...


In Green building techniques | Asked By Scott Miller | Jun 23 11
1 Answer

I live in an ICF home. We have an HRV system and A/C. However the humidity is 68%. How do I get rid of the humidity?

We live in central Illinois where the humidity can be high. We just moved into our home in April so we are new at this.

From what I have read am I right in assuming the only way to control this humidity is by using a dehumidifier? If so should i use a free standing one in the house or one that is installed on my HV system. How often should i be running the HRV system?

In General questions | Asked By randall muller | Jun 23 11
1 Answer

Drainage mat behind stone veneer?


Is it preferred to have a drainage mat in the air space with a stone veneer (as I typically specify - EnkaDrain-standard) )


Is it OK/ better to delete the mat and the air space (to minimize the opportunity to form condensation) and fill behind the veneer solid with mortar?

I would provide weeps at the bottom of the wall for water to escape in any case.


In Green building techniques | Asked By Debra Cedeno | Jun 22 11
4 Answers

Garage ventilation requirements/calculations?

Working on an energy retrofit project and the client is wanting mechanical garage ventilation. I'm having a hard time finding information about how to figure out how much he needs. Is it just a matter of how much he wants? Some other discussions online seem to be about commercial garage areas, but others seem to have calculations for residential ones. Some direction for where to search, or some answers outright, would be most helpful.

In Building Code Questions | Asked By Bradley Yoder | Jun 22 11
5 Answers

How can a slab edge be tied into a foundation stem wall and insulated at the same time?

I'm working with the local code officials to find a way to insulate a slab to a footer or stem wall. They are concerned about termite infiltration and structural issues when tying the insulated slab into the footer with rebar. One jurisdiction is allowing R-5 placed horizontally but nothing on the slab edge. I told them the requirement does little for stopping heatloss through the edge. Attached is a design they came up with but the local HBA rep. on the board expressed the concerns listed above.

Connecting the slab through foam products with rebar poses its own set of problems.

In Green building techniques | Asked By Bruce Chyka | Jun 21 11
7 Answers

Can anyone forward me an article as to why we do not recomend puting Ice & Water sheild on the exterior of a building?

We are currently building a new building at Mt. Snow, VT to house there private water system equipment. There resident Engineer is insistant that we install Ice & Water sheild over the exterior sheilth to protect it from the deep winter snow drifts. We proposed using Dow building wrap taping al the seams. Vicor at all doors & window locations. The foundation is concrete with a suspended first floor (concrete) and the foundation called for no insulation or sealent/membrane system.

In Green building techniques | Asked By Matt BLANC | Jun 20 11
4 Answers

Bad HVAC Install?

A few fishy things with my HVAC install, wondering if any of these are real bad... my installers cut corners wherever they could.

1) The return air receive box (where my 2 return airs feed into - that connects to the furnace unit in the attic) is sealed to the unit on all sides (tape and paste), however the bottom seam of their connection is NOT sealed.
There is a lot of soot that looks like it went in thru there from my dirty attic. That is bad right? Or is that supposed to be open? I think it may be the cause of #2...

In Energy efficiency and durability | Asked By Ryan Gullahorn | Jun 21 11
1 Answer

Multiple vapor barriers within a wall assembly

I was reading Martin's column in the Green Building Adviser regarding “All About Water Resistive Barriers” (January 2011). I have a specific question in mind which has to do with a siding replacement project.

In General questions | Asked By Brian Westerhout | Jun 21 11
4 Answers

Grailcoat on SIPs Repairs

I have a client with a failing Grailcoat job in NC. The house is framed with 6" Insulspan walls. The Grailcoating apparently cracked, let in water, and there are numerous soft spots in the outer layer of the SIP's OSB.

1. Has anybody had a Grailcoat job fixed?

2. Did the fix work, and what did it look like?

3. What is the proper way to repair a SIPs panel?

Thanks for any help.

In General questions | Asked By John Eshelman | May 8 11
1 Answer

ICF Wall system with Brick veneer - Full brick or Thin brick?

I have a 2-story ICF showcase home we are building in Central Florida. My gut tells me thin brick is the better route. Unfortunately, I must be the first builder in CF to build with brick over ICF and have no details from the architect or manufacturer specific to ICF with brick. The biggest problems to solve are figuring out the details around doors and windows and where the first floor roof deck hits the 2nd story ICF wall…any comments?

In Green products and materials | Asked By Greg Hardwick | Jun 20 11
Register for a free account and join the conversation

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