Community: General questions

Q & A Instructions

[Click map to enlarge]

The 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!

8 Answers

Surface-mounted LEDs

I understand how recessed lights are a problem with air sealing, so I want to go with surface mounted LEDs wherever I can. So, how are these mounted and wired? Is a 4" box sealed with foam and then the box sealed to the ceiling, followed by the surface mount?

Also, are there any smart LED fixtures that work with Google Home?



Asked By Norman Bunn | Aug 16 17
1 Answer

Sealing exhaust fans

Most exhaust fans you get from Home Depot have tons of places for air to leak through. Is there a good way to seal these or are there better fan options out there?



Asked By Norman Bunn | Aug 16 17
6 Answers

Re-roofing a flat roof in Utah


I'm re-roofing our flat roof single-story home in northern Utah -- dry summers and sometimes snowy winters. Air humidity is very low and we get about 19" of precipitation, much of which is snow. We have about 2650 ft2 of conditioned space (walk-out basement) and used 510 therms of natural gas last year for heating at a cost of about $500 with a forced air gas furnace that is probably < 75% efficient. The interior of the house is tight based on a blower door test.

Asked By mtaylor12345 | Aug 15 17
3 Answers

Quick question about repairing an expansion joint in concrete

The joint is about 3ft x ~1.5 inches and the gasket put in place by the builder is long gone. I plan to install a new gasket and top off with the appropriate caulk/sealant.

Since the gap has been neglected I anticipate having add fill with some sort of material.

Q: What material should it be? Sand or soil? I have an opened bag of potting soil that I could tamp down in order to raise the gasket to the correct height. I'm thinking maybe a half inch of fill.


Asked By John Clark | Aug 16 17
12 Answers

Renovation to address heat gain (summer), heat loss (winter) and ice dams

We have a home at about 6000 feet elevation in Utah. It’s dry, and the temperatures can vary from below zero F in winter to over 100 F in summer. Our house was built in 1994 with some attic space and lots of cathedral ceilings. From what I have observed, the roof/attic was not insulated well when built. This has been partly remedied by blowing in extra insulation into the attic, but most of the cathedral ceilings where framed with 2”x12” with probably 8” or 9” thick batts of fiberglass. In short, the roof has lots of heat gain during the summer and lots of heat loss in winter.

Asked By Chris Butson | Aug 13 17
5 Answers

Garage with in-floor heat

I live in a northern climate where freezing temps and snow is a common occurrence during the winter months. I am planning to build a new garage using hot water in floor heat. I was told by the plumbing contractor that in floor heat is not advisable unless a ventilation system is installed as well. Along with floor drains. The reason for the ventilation system is to guard against mold growing in the insulated walls caused by the evaporation of water from snow melting off the vehicles.

Asked By Pokegama | Aug 15 17
1 Answer

Slab and frame issue

What product would be best to seal between a slab foundation and the frame? Am getting outside bugs in and I was told by our HOA that others have had this issue.

They suggested an spray foam insulation.

Asked By Kim9131 | Aug 15 17
5 Answers

how to insulate around a ceiling light can in and attic and loose as little thermal loss/ leakage as possible?

If one uses compact floresent bulbs which do not get as hot as incandesent, how close can you get the insulation next to the light can?
.........Terry Nordbye - North Bay Green

Asked By terry nordbye | Jan 29 09
5 Answers

Insulated cathedral ceiling question

I reviewed your article on this topic ( but am hoping to get your thoughts about my specific variation in mind.

I'm constructing a small (12x24) guest cabin with a "modern" post and beam frame. The plan for the (cathedral ceiling) roof assembly is v-groove over the rafters then 2 layers of rigid polyiso sheets staggered and taped, house wrap then Advantech screwed to the rafters followed by asphalt or fiberglass shingles over felt paper or whatever material is appropriate for the product.

Asked By MF-NH | Aug 12 17
5 Answers

Temporary bracing for small trusses

I'm installing standard trusses with a 20' span, 2' overhangs, and a 4:12 pitch for a simple gable roof. The truss drawings indicate that the only permanent bracing needed is sheathing on top and a drywall ceiling directly attached on the bottom, both of which I'll install.

Asked By Jeff Cooper | Aug 12 17
Register for a free account and join the conversation

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