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!

1 Answer

Refinishing painted cinderblock walls

1954 rambler in Minneapolis, Minnesota here. I am in the process of refinishing our basement after some slight water intrusion last year caused us to discover mold growing on our old tar paper behind knotty pine finishes. We concluded it was due to water weeping behind the walls and then collecting on the tar paper, a problem that had been ongoing for decades with no obvious failure until now.

In General questions | Asked By fishybass | Jul 17 17
5 Answers

Air sealing kneewall with I-joists beneath

Hey my name is Josh and I live in Maryland zone 4. Excuse if my terminology is off, that's why I'm including some pictures. I just moved into a 2002 built 1 and 1/2 story home. I'm trying to do everything I can to seal and insulate the home because I don't the builder had energy efficiency in mind.

In Energy efficiency and durability | Asked By Joka | Jul 16 17
17 Answers

Synthetic roof underlayment (low perm material) as Stucco WRB?

Given the history of prior stucco failures and what we have learned, would it not be prudent to use a WRB with an exceedingly LOW perm rating with a wall assembly designed to dry to the interior? I am planning stucco on a residential structure in Zone 5 (despite the barrage of don't do its, it fits the architecture of the home). Thus have been stopping into jobs randomly where stucco is being installed and find most contractors apply two WRBs under stucco. I've seen a wide permutation of choices.

In Energy efficiency and durability | Asked By Sal Lombardo | Jul 9 17
22 Answers

Properly installed can light vs. surface mount

I am doing more research in lighting after an earlier question and reading other articles. The general consensus I am seeing is: Can lights are evil. The logic? Because of air leakage.

In General questions | Asked By Nicholas C | May 1 17
5 Answers

Exterior foundation waterproofing

I recently had my foundation wall treated with a spray on waterproofer. I noticed a week later that there were little pin pricks throughout the black layer. Some of the pin pricks you can see concrete through. Is this a typical occurrence or should I have the company spray the wall again? I am mostly worried that it will cause the waterproofing to be defective due to moisture instrusion. Thanks!

[Editor's note: Photo below.]


In General questions | Asked By Chris Roche | Jul 16 17
4 Answers

Roof retrofit for non-cathedral, non-low slope roof

I've read several items about adding exterior insulation to existing roofs but haven't found the detail that I'm looking for.

We have just purchased what amounts to a one story ranch home with a walk-out basement in Central WI built in 1985. The basement is block except for the walk-out wall. The walls are 2x6 stud construction with fiberglass and poly. The gable roof is framed with standard (not energy heel) trusses 2' o.c at 4/12 pitch. There is a also a small intersecting gable addition with that roof framed on top of the original gable roof.

In Green building techniques | Asked By Scott Lind | Jul 14 17
4 Answers

What is the optimum insulation and roofing solution for a low-slope cathedral ceiling/roof?

I need some advice, please. I own a mid-1950s rancher with a cathedral ceiling/roof in Hershey, PA. The slope of the ceiling is about 3 ft of rise in 11 feet of run. The ceiling is drywall, to which acoustical tile is attached. The character of the space from the ceiling to the roof is unclear. The gap between the ceiling and roof deck is 6 inches. The roof is unvented. The soffit does have some venting, but it does not seem like a lot. The "attic" has fiberglass batt insulation that likely is in failure. The problem is interior moisture.

In General questions | Asked By Need to learn | Jul 15 17
2 Answers

Any new insight on Air Krete?

I've read the other posts, which are a few years old.

Does anyone have any new advice or guidance using the product? I have a client that is interested in the product. Specifically looking for any known issues or installation advice.


In Green products and materials | Asked By Cliff kornegay | Jul 20 16
2 Answers

Air Krete

Air Krete seems like an incredible product. Everything about it sounds great. R-value of 6. Inert. No VOCs. Fire Resistant.

How many builders, retrofit contractors are using this?

It does not appear to be widely popular but it seems like a dream come true.

What am I missing here?

What's the catch?

In Green products and materials | Asked By Reuven Walder | Aug 7 14
9 Answers

Kneewall insulation planning stage - Thoughts appreciated

Hi All,

I have read all the available articles and Q&A on kneewall insulation, including Dana's comments on playing the fool on multiple occasions and therefore would appreciate your views on my situation / questions / possible approach.


- Climate Zone 5 (Chicago area)
- Walk-in closet over attached 2-car garage (20ft x 8ft space)
- Garage attic has soffit and ridge venting and this attic is isolated from the rest of the home's attic space, except for one HVAC duct which comes from the "main" attic. This duct runs above approximately half of the kneewall ceiling

In Energy efficiency and durability | Asked By Joe Duchek | Feb 10 17
Register for a free account and join the conversation

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