Community: Energy efficiency and durability

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!

5 Answers

I live in an 1890 Victorian in Southern Pennsylvania, heated by oil. While I love radiators, I hate using fossil fuels! Is there a way to use green technology to use less oil? My methods to date have been uncomfortable - installing a wood stove,

Is there a way of boosting the boiler with green energy? Would geothermal help? I'm newly divorced and ignorant about systems!
Thanks, Susan

Asked By Susan Hanway | Aug 28 16
2 Answers

Cathedral unvented ceiling in California

I live in Santa Barbara, CA (ideal climate) and I am remodeling a home. The roof was built in 1975 by the prior owner. The roof from top down and ceiling are comprised of shingles, paper, 1/2" plywood sheathing, 3/4" foam board, then 1 3/8" tongue and groove. All materials are sandwiched together with no air gaps. The roof is supported by exposed rafters/beams.

Asked By Jeff Swaim | Aug 28 16
7 Answers

DIY heat recovery and ventilation question it's been a while. We completely destroyed and then rebuilt our 1800s house and aside from some trim and exterior improvements...we have been comfortably living in it now for over a year with many thanks from this site. We used the cut and cobble insulation system combined with blow in with a mooney wall to keep our house very energy efficient. Even in the deep cold of winter our heat bills are below 100 bucks in a 1400 square foot house built over 135 years ago.

Asked By Geoffrey Cook | Aug 24 16
1 Answer

Can you use rigid insulation only? Exterior wall in zone 1

We are enclosing a screened porch, reinforcing exterior walls on a 1969 trailer and then we plan on putting up rigid insulation over plywood sheathing and existing aluminum

Asked By Jennifer Earp | Aug 27 16
9 Answers

Insulating a finished garage with unvented cathedral ceiling

Hello -

I am hoping for any input/advice about insulating my garage, which I'm in the process of finishing. The details are:

This is a 20 x 20 garage, uninsulated concrete slab floor with an epoxy finish on it. Unvented roof which will have drywall up to the peak. The walls are ordinary 2x4, the ceiling is 2x6. The garage has several windows, all double-page argon/low-E and a insulated garage door that seals surprisingly well (but it's still a garage door).

This is in Denver, CO zone 5.

Asked By Dave H | Aug 9 16
5 Answers

Cellulose over 1/2" drywall and 24" o.c. furring strips


Asked By Marc Delisle | Aug 26 16
8 Answers

Polyiso sandwich with synthetic underlayment

I'm located in Central Texas (China Spring, TX) and am building a house with my wife. The house was originally started by the previous owners and we are replacing and redoing quite a bit of it at the start. We are doing the majority of the work ourselves (taking forever) and we are at the point of finishing the roofing

Asked By Jacob Cox | Aug 24 16
5 Answers

Spray foam the ceiling joists vs. the back of the roof sheathing?

Is there ever a time when an attic space is so large that it is better to spray the ceiling joists rather the backing of the roof sheathing?

(No cathedral or vaulted ceilings…)

The home is ~6000 sq ft under roof (including garages) the builder is thinking that it is better to spray the ceiling joist since the attic space is so large.

(There are areas were the ridge row is ~15+ ft above the ceiling joists.)

His logic is why  do I want to cool the attic and that my electric bill will be higher since I’m heating/cooling a larger area.


Asked By Cynthia Richards | Aug 23 16
3 Answers

Embedded floor joists air sealing

I have a 1960's bungalow in Canada where the 2x10 floor joists have been embedded/cast into the concrete foundation wall. The foundation wall stops about 1" below the floor sheathing.

I have been considering insulating the rim joist area but because of the embedded joists I don't feel this is a very good idea because of the potential for the joist ends to rot in winter. It seems the best option is to leave that area un insulated.

Asked By David Red | Aug 23 16
23 Answers

Basement subfloor retrofit insulation options

We recently renovated our 1897 brick workman’s cottage here in Chicago. We’ve done our best to upgrade the energy efficiency of it including insulation upgrades– although based on some of threads, may have made a few not optimal decisions (closed cell soy foam interior – we’re in an historic district so we cannot make any changes to the exterior.). We’re now seeking to tackle our basement floor, specifically insulate it.

Asked By brandon antoniewicz | Nov 30 10
Register for a free account and join the conversation

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