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!

0 Answers

Am I asking for trouble?

I may need to switch to a 2x6 load bearing exterior wall as my outer wall cannot be load bearing but had to be changed to a "Larsen" like truss. To maintain about the same total wall depth I'm considering an inner 2x6 load bearing wall sheathed on the exterior with OSB and filled with mineral wool r23 and a modified Larsen truss 2x6 wall outside. I'm envisioning the trusses as frames of 1x2 with pieces of Thermoply on one side at both ends and filled with mineral wool (about r19). Should I stagger the studs? or put them inline?

Asked By Jerry Liebler | Sep 21 17
0 Answers

Insulation under floor joists in a crawl space

I have recently installed a new tile floor with electric radiant floor heating over a crawlspace and am looking for the most economical way to insulate the floor. If a radiant barrier blocks 97% of the radiant heat is it necessary to install foil faced EPS on the bottom of the joists for more insulation at three times the cost?

Asked By pickaname | Sep 20 17
4 Answers

Pros - How Would YOU Build?

This question goes out to the pros on this site; those who are builders, building science aficionados, or some mixture of the two.

Many folks, myself included, come here with some vague ideas of how they think they would like to build and then post their ideas asking for advice. Instead of starting somewhere and then working backwards, I'd like to know where the pros would start. So here we go:

Asked By Lance Peters | Sep 18 17
0 Answers

Taping OSB sheathing to ICF foam

Does anyone have experience with an effective tape for sealing OSB sheathing to the ICF stem wall foam?


Asked By Brett Greenburg | Sep 20 17
10 Answers

Is there a reason people do not use hydraulic cement to parge an entire stone basement?

I have a stone basement in Wisconsin. It's depositing sand along the edges of the walls in various spots. Not bad, and it only leaks a small drizzle of water if there is a huge downpour, but I want a clean water tight basement.

Asked By PFields | Sep 17 17
1 Answer

Zip vs. Thermo-Ply in retrofit wall assembly

I am a homeowner renovating a 100-year old foursquare in Manhattan KS (mixed-humid, zone 4). We need to remove our wall sheathing to address some dry rot issues, and are taking the opportunity to improve the envelope details and work closer to a pretty-good house.

The walls are 2x4 balloon framing with interior lathe-and-plaster and 1x12 exterior board sheathing. The cavities are insulated with blown cellulose. After repairing the rot, our plan is to add the following layers on top of the existing board sheathing:

1 – ½ Zip system panels with taped seams

Asked By Nathan Bean | Sep 18 17
11 Answers

Cape Cod--Building a maintainable insuated roof (on the cheap!)

We are purchasing a Cape Cod style home near Dayton, OH (climate 5A, but the southern edge). I've read many of the helpful articles here (thanks, Martin, for the notes about Capes here: . I can't say I wasn't warned!)

Other articles I found very useful:
This situation:

Asked By Mark Waldron | Sep 11 17
3 Answers

Turning off/setting back ductless minisplits, kwh, efficiency, and more

So I talked to an LG engineer today (hint: if you have questions about minisplit performance, don't call tech support, find the number to a local manufacturer and ask to talk to their engineer).

My 4 ton LG LMU48HV condenser can cool down to 14,400 btus. At that minimum, the system will use around 900 watts. This was actually verified by my Efergy Elite monitor, which showed that during 82 degree outside temperature, 3 of my indoor units were on, and it showed a pretty constant energy use of 900 watts for the 8 hours that it was on (2 pm - 10 pm).

Asked By Jimmy Nguyen | Sep 15 17
4 Answers

Sub-slab insulation

I was planning on using 4" of Type II EPS covered with 10 mil Stego under my slab and 2.5" of EPS on the basement walls. I spoke with my concrete guy today and he told me they have been using this product:

Asked By Jonathan Lawrence CZ 4A New Jersey | Sep 13 17
2 Answers

How much do oil-based stains affect vapor permability?

Hi guys,

I stained my siding recently (bevel siding) with oil based stain.

Since my house is built fairly vapor open, I am curious how much oil stains will affect the vapor permability of the building's envelope and ability to breath?

I am guessing it leaves the wood still semi vapor permeable because almost every house has paint/stain.

How do you guys approach this when building a vapor open house? Even if it makes it vapor closed, I do have 1/2" furring strips behind my siding, so would that be suffecient to allow vapor to escape from the house?

Asked By MichaelBa | Sep 13 17
Register for a free account and join the conversation

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