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!

0 Answers

Slab on grade retrofit - Climate Zone 3C

Hello all,

Asked By ELLE55 | Mar 28 17
7 Answers

Building a new home in Climate Zone 5 — Need insulation help

We are building a new home in zone 5 (Michigan) and I would like your recommendations on how you would insulate the walls and roof/attic space.

The home is 3500 sqft with 2750 on the main floor and 750 upstairs. The main living space (kitchen, dinning, living room) is open concept with a cathedral ceiling. Other areas have a more traditional attic space.

The basement will be unfinished and we will use 2" rigid foam under the slab and on the walls. (unless you tell me differently)

Walls are 2x6 construction.

Asked By NKoenig | Mar 26 17
25 Answers

Hydronic Heating System Hydraulic Buffer Tank vs Hydraulic Seperator

This question might be more appropriate in a plumbing forum but I have had such great and thoughtful responses in the GBA forums I look to here first. This is also a hydronic heating mainstream topic which should be appropriate for GBA.

Asked By Roger Smith | Feb 26 17
0 Answers

Flooring approach in climate zone 3A basement

Hey folks,

I'm planning on finishing by basement and am looking for some advice on the flooring assembly. I posted something similar about the walls a few weeks back. http://www.greenbuildingadvisor.com/community/forum/energy-efficiency-an...

Some quick information: Climate zone 3a, poured concrete slab, no insulation under slab, no bulk water issues so far, new house constructed in 2016.

Asked By Jamie Royal | Mar 27 17
5 Answers

Different one-part foams

Hey folks,

I'm installing XPS/EPS rigid foam against my basement walls. I've seen and read on FHB using low-expanding as the adhesive to hold the foam on the walls. I'll be framing a 2x4 wall in front of the rigid foam, so the adhesive only needs a moderate hold.

Great Stuff Window & Door is by far the most common spray foam I see. Its in the big box stores, Amazon, etc. I've put up a few rigid foam sheets in the basement as a test with the Great Stuff and the hold is fine.

Asked By Jamie Royal | Mar 26 17
1 Answer

EPS Foam Density for Under Concrete Slabs and Around Stem Wall

Hi everyone,

I'm right at the point where I need to purchase some EPS foam for our slab foundation / stem wall on a residential net zero project. I've read and posted on the project in the past and there seems to be a consensus that Type II EPS foam should be fine from a compressive strength perspective in both applications.

Asked By Joshua Greisen | Mar 27 17
10 Answers

Building a new house, looking for opinion on insulation/exterior foam combinations

I am currently in the process of designing a new home. I built one four years ago that we have decided is too big and inefficient for what we need. This time around I am looking to build small, simple and efficient. The house will most likely be framed with 2x6 walls, however I would like to maximize R value of that wall.

Asked By user-6801629 | Mar 23 17
0 Answers

How to vent attic that has no eave.

In an older building. The problem is ice dams more so than energy cost reduction. The roof design is more complicated than I can explain easily here.

I am considering using these vents. however they look designed for new not retrofit construction. Any experience with this type of vent.


thanks in advance

Asked By walt ott | Mar 27 17
11 Answers

Low-slope "warm" roof build-up clarification

We are advancing on the planning stages of a new build project in climate 4C (near Vancouver, Canada). Thanks to the many articles and Q&As on this site I've got myself comfortable with most outstanding issues we are facing in developing our roof and wall build ups. This is a small building used as a holiday home, not fully occupied in Winter.
With that in mind any feedback from your good selves would be appreciated.
The roof is a mono pitch (shed style) front to back at just 1:12 with no "rafter" space to hold insulation
Build up:
- Exposed 3X8 Douglas fir beams

Asked By Quinn Sievewright | Mar 26 17
0 Answers

Taping Seams in Plywood for Health Reasons?

Climate 4C. I am debating the cost and effort of taping our plywood sheathing. Due to a few circumstances, we changed our building wrap to doubled up 60 minute paper, attached to furring strips (closed rainscreen). Alternatively we are considering a hybrid product called Hydro-Tex, which is tar paper that has a drainage plane on the backside. Either way, is there a risk of this petroleum based product causing health problems, which the inhaling of off-gassing? I know most people who tape plywood seams do so for energy reasons, but is it reasonable to do so more for health reasons?

Asked By Mike Dominic | Mar 27 17
Register for a free account and join the conversation

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