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

Older home (1950s) smells of mildew...

I purchased a home in late 2009 and have been trying to get rid of a heavy mildew odor. Last week I discovered the seller had put vinyl siding over two layers of other siding. Underneath the vinyl was a layer of extremely damaged Boise Cascade panel siding. It was crumbling and had large holes in multiple places (no house wrap). Behind the holes I discovered clear plastic sheeting and underneath that was cedar lap siding. I continued on down to the Buffalo board that was somewhat warped and had a strong mildew odor.

Asked By Terri Gerhart | Jul 1 15
6 Answers

It's 2015 and they still build like this...

Brand new build going up in Phoenix, AZ. What you see is completely 100% framed and ready for stucco. The missing OSB sheathing is done on purpose. They do "open framing" and only use sheathing where required. The rest is open 2x4 framing.

They will stuff R-13 batts within the 2x4 walls, staple on some building paper and then put 1" of rigid EPS on the outside and use conventional stucco to finish it off.

A recent blower door test on a home like this showed 15 air changes per hour.

ALL of the duct work and air handlers are installed in the 150F unconditioned attic.

Asked By Peter L | Jul 1 15
12 Answers

Foam over a concrete floor

I plan 4 - 6 inches of EPS under the slab and now am considering an inch of either EPS or XPS on top with 5/8 or 3/4 tongue and groove plywood or OSB to provide a nicer floor to walk on as well as a warmer floor in the walk out basement. I think this will make it easier to attach partition walls and tile in the bathroom and hardwoods in the sunroom.
Question. .. Is this a good idea, and do I glue the foam (EPs or xps) to the concrete and the sheeting to the foam or leave it free floating?
Any gotchas in this?

Asked By tim brown | Jun 29 15
4 Answers

Closed-cell spray foam in conditioned crawl space, sill gaskets, windows, & air sealing

We have our house plans back from the designer and are getting ready to start building. I have a few separate questions:

Asked By Michael Geoghegan | Jun 30 15
1 Answer

Can a feature be added to e-mail on a reply?

If i want to follow a conversation, I have to come back to it and sometimes it ends up on the second or third page. It would be very convenient that once I reply to someone's question, I get an e-mail when it gets replied to by someone else.

Asked By Alan B | Jul 1 15
3 Answers

Foundation capillary break & waterproofing

My wife and I are building a small home (First Day Cottage) on a full foundation with a walkout on the downhill end. I read about having a capillary break between the footing and foundation wall and it makes sense to me. When I asked the concrete contractor about it he said he's never done it (though he did remember one other customer who asked about it a couple years back). I get the impression they won't leave me much time to do it myself between pours.

Asked By Martin Frank | Jun 30 15
3 Answers

New Unvented Attic and High Humidity

Last year after a severe hailstorm the attic insulation and the entire roof deck of my 1600 sqft ranch style home in Fort Calhoun, NE was replaced. With the replacement we upgraded the insulation to Open Cell Icynene spray foam on roof decking. The spray foam is at least 6-8 inches on the roof, and covers the sidewalls, soffits, and attached garage ceiling. This completely closes in the attic to the thermal envelope of the house. I've been monitoring the relative humidity levels of the house for the last year.

Asked By Nick Schuler | Jun 30 15
8 Answers

Is my 5000 BTU LG 10 year old window unit significantly inefficient ?

My wife says so, in comparison with similar modern window units. She wants it replaced. The unit runs on all work days, during summer work hours, in my home office in San Antonio, Texas. San Antonio summers are hot, but not as hot as north Texas, as an example comparison. My question is whether efficiency advances in 10 years have made a big difference for small window units.

I tried to search, but every search returned hundreds of irrelevant topics.

Asked By Weldon Cabaniss | Jun 28 15
6 Answers

Trapped moisture on SIP roof

I knew SIPs were the Achilles heel of my 100% engineered house design, But because of inattention to detail, heavy rains at a critical time of my house build pushed water underneath the PVC membrane (applied on mechanically fastened DensDeck) onto my SIP. It happened the night before the adjacent wall could be spray foamed to properly seal off the membrane. Unfortunately, the spraying was later done to the walls and the underside of the SIPs without knowing there was water present.

Asked By Edward Mallett | Jun 29 15
52 Answers

Attic hot after closed cell spray

Finished attic with 4 foot knee wall , duct located in knee wall to support 2 floor,extremely hot, BASF spray tite 2 inches with spray foam wraped around rafter in knee wall but with Sheetrock on ceiling just 2 in foam In cavity . Suggestions to handle heat issue. Richmond Virginia all attic seal very well thinking heat coming from rafters under Sheetrock. Thermal convection coming from rafters. Worked done in the winter, crawl space also done, house built 1994 colonial 2 story with garage with room above with dormer. Also in crawl space does it really need supply vent and return vent

Asked By Mark hippchen | Jun 27 15
Register for a free account and join the conversation


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