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

Where to buy EPS foam (25 psi, termite-treated) for use under a concrete slab in West Virginia?

If someone could assist me it would be much appreciated. I have spent several days calling and searching the net. I am building a house with a large basement using superior walls. I want to insulate under the slab with 2 inches of eps foam but I cannot find anyone near that sells it. I want eps not xps. The house is being built near Charleston wv. I would not care to drive 1-2 hours to pick it up, but would like to find a company that could deliver it to the construction site. Closest I could find was a 6 hr drive and they would not deliver. Thanks for any help.

In Green products and materials | Asked By Chris Burgess | Apr 28 14
1 Answer

Custom polyiso roof-vent baffles + traditional unfaced fiberglass batts + poly vapor barrier (conditioned space) = Success?

If I build custom roof-vent baffles with polyiso board then fill the remaining cavity with traditional unfaced fiberglass batts, can/should I also install a Poly vapor barrier prior to dry-walling? If so what mil thickness would be recommended?

I am concerned that the PolyISO board would create a vapor barrier and then the poly roll would create another barrier and any leaks could cause moisture to become trapped in the batts and rot the rafters.

In Energy efficiency and durability | Asked By Logan MacKinnon | Apr 28 14
2 Answers

Crawl space fans

Hi

Does anyone have a recommendation for crawlspace exhaust fans?

Would an appropriately sized Panasonic be the simplest option?

In Mechanicals | Asked By Jill Neubauer Architects | Apr 21 14
3 Answers

I'm building an energy-efficient, hopefully net-zero house in Southern CT.

I've selected a Solar PV engineer/installer who offers either mini-inverters, on each panel, or two inverters in the house. The price is the same. I'm seeking advice on the pros and cons and which option is best.

David Dickson
dd6270@gmail.com

In Energy efficiency and durability | Asked By david dickson | Apr 28 14
2 Answers

Slab Foundation Insulation

I will be building a home in North Central Texas. I was wondering if it is reasonable to insulate with foam board on top of a slab foundation and of course below the flooring used. I have seen foam board used below a slab but not on top. My thinking is there is energy loss due to the HVAC system constantly having to heat and or cool the slab that pulls ground temp into the home relative to the season. Also the heating and cooling of the slab from the exterior of the slab pulls the ambient temp from outside.

In Green products and materials | Asked By David McLamb | Apr 28 14
1 Answer

Ductless Air Exchange

Hi

Approx 2 years ago I found a Fantech air exchange unit that goes against the outside wall and will bring fresh air in and stale/toxic air outside. It was very affordable, under $400 and could be installed by an electrician quite easily. I placed a link in my email and now that I'm ready to move forward the link doesn't work. Fantech says they have no such unit. I'm beyond frustrated because I had spent a long time researching for it.

In General questions | Asked By Shelley Davis | Apr 28 14
2 Answers

Does anyone have experience or knowledge of injection foam from USA Insulation?

They specialize in injection foam for retrofit applications. Their using a phenolic based methylene-linked synthetic polymer that is poured in to a wall cavity as a semi liquid. My concern is, has there been any independent study on the foams reliability and the manufactures claims?

In Green products and materials | Asked By cameron morris | Apr 27 14
3 Answers

Energy-efficient tack room?

We are adding a tack room to our barn this summer Climate zone 4a but near the edge with 3a). The reasoning is to provide more secure and better storage for the tack for our horses (consisting of a few saddles, driving harnesses, halters, blankets etc...)

Most of the tack rooms I've been in are just rooms built in the barn. They do a reasonable but not great job of keeping the dust and critters out. However none that I am aware of do anything to condition the space.

In General questions | Asked By Donald Endsley | Apr 25 14
6 Answers

Spray foam layer over board foam in Northern Zone 5a?

Mr. Holladay once wrote of rafters, "Yes, you can combine rigid foam and spray foam if you want to save some money. I would be inclined to install the layers of rigid foam first [I, Gordon, assume this means the rigid foam would go against the roof decking] -- cut undersized, and with canned foam sealing the perimeter of each rectangle -- and cap everything with spray foam [I'm seeing this as under the rigid foam and further away from the roof] from a contractor's truck."

In Green building techniques | Asked By Gordon B | May 23 13
3 Answers

Electric tank water heater?

Hi. I am back and forth about purchasing either the Rheem Marathon or your run-of-the-mill steel tank electric hot water heater. I have read that the Marathon series is no more efficient than a standard tank (EF factor), however, has the advantage of not rusting out. So what's the advantage of all that foam on the Marathon? It costs 2/3+ more and its tank is made out of polybutylene which is a bit worrisome. Any recommendations on kind, as well as sizing (2 adults, 2 kids; are fairly water conservation minded); I'm thinking an 50-75 gallon would work?

In General questions | Asked By Matthew Michaud | Apr 26 14
Register for a free account and join the conversation


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