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!


13 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
10 Answers

Which long screws are really necessary?

HI

So I know an engineer should confirm everything, and are useful in most cases ,but lets see if I can get cheaper advise and experience form others. (I have paid for numerous other required Eng. stamps).

Also this is a storage/work shop so I am not as concerned.

I'm looking for best bang for the dollar(LIKE EVERYONE) in a 6" screw for holding my horizontal furring strips on the walls. I'm in Ontario Canada, so less choice of stores willing to ship.

Wall inside -out
2 x 6 stud wall @ 16" OC.
7/16 OSB sheathing
3" Polyiso
tyvek

Asked By Dave B | Sep 9 17
2 Answers

Subfloor for new covered 3 season porch?

I am planning a new 12'x12' 3 season covered porch attached to the house in far northern Minnesota. The footings are pinned to solid ledge rock, so there is no chance of this thing moving. I'm using pressure treated ledger and 2x10s joists.

The porch will be about 4' above the grade. The underneath of the structure will be protected from critters by heavy screening and a trellis. However, it will be exposed to outside air movement and temperature and humidity swings.

Asked By Steve Lenertz | Sep 23 17
3 Answers

Window sill detail

Attached are my "current" elevation and 3-D details for my "innie" window install. I recently added the beveled sill.

Do you think I need to take that beveled sill to the front edge of the Roxul so it will drain down the rainscreen? Any comments on the rest of the detail?

Thanks.

Asked By Jonathan Lawrence CZ 4A New Jersey | Sep 22 17
4 Answers

Do I need drywall between rafters and T&G wood plank ceiling?

I have read a number of articles about unvented cathedral ceiling design. I'm a diy guy rennovating a 1978 brick ranch in Nashville, TN. Im not sure what climate zone I'm in. By the map, I think I'm in 4, but code requirements seem to be based on 3. I think I've read just enough to get unsure of myself. I will hire out all of this work, but I want to make sure the right things are being done to optimize my insulation and not cause more problems. I know there have been several posts on this subject, but I haven't found anything that is related clear on my exact setup.

Asked By ecfelts | Sep 22 17
7 Answers

Clarification on unvented cathedral ceilling

Hello all, this is Annie. I needed some help with my roof assembly. I have tried to put this in the comment section under Mr. Martin Holladay's article about unvented cathedral ceilling but the system blocked my post. So if it cleared out and anyone has seen repeated questions I posted, I apologize here first.

I am in central Alabama, Climate Zone 3, and in the middle of building a tiny house on wheels. My roof is a very low slope almost flat shed roof (1/2 to 12 pitch) and I have decided to finish it unvented.

Asked By Maiter | Sep 22 17
11 Answers

I am looking for the best ideas for a project for my high school Green Building class

I have been teaching a green building course to high school kids for 4 years. We design green buildings that are enegy efficient using the 3D BIM software Revit and learn all the latest construction techniques and standards. A lot to learn!
What I am looking for is a good hands on project ideas to apply all the theory and design.

Asked By tim eberhardt | Sep 19 17
8 Answers

Install rigid foam while the wall is lying down

Has anyone tried installing the rigid foam EPS or XPS while the wall is on the floor deck and then installing the plywood over the foam overlapping foam seams before lifting the wall into place ?

Asked By susan cosentini | Jul 26 17
2 Answers

Once again, the New York Times flubs an article on green building

Today's New York Times announces an exciting new type of housing.

The article describes this housing option as:
- "eco-friendly"
- "sustainable"
- "a legitimately green option"

What's the article talking about? Homes made from shipping containers, of course.

Here is the link:
https://www.nytimes.com/2017/09/22/realestate/home-in-shipping-container...

Asked By Martin Holladay | Sep 22 17
14 Answers

Typar vs Zip

I was thinking about using the Zip R system sheathing on my house - removing old clapboards, insulating the wall from the exterior and then installing the ZIP R. I just attended a seminar with a Typar house wrap rep who basically said Zip was no good - is not surfactant resistant and not much more that felt paper glued to OSB. But of course this is coming from the Typar rep. Any thoughts on the pros and cons of each?

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


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