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!


3 Answers

I am having a house built and have some questions about the crawl space.

This is a northern Idaho climate and the house was designed to be at garden level. There is a crawl space and the floor joists were originally designed to be hung with Simpson hangers below grade. Instead, there was a short support wall placed on the footings and the floor joists are sitting on the short wall. We intend on making the crawl space conditioned/mechanically ventilated. The short wall was installed within 1/8 of an inch of the foundation wall.

Asked By justin edwards | Jan 21 17
6 Answers

Vapor Barrier on top of SIP floor?

We are working out the details for the construction of our new house in the Pacific Northwest. Our architect and structural engineer have specified a 9 1/4" SIP floor for the 1st floor. Since we will be building in a flood zone, our foundation will be an open design with concrete columns extending from a mat foundation. Horizontal beams will sit on top of the columns and the SIP panels will sit on top of the beams. The structural engineer has specified a factory treatment of "bluewood" preservative to the bottom face of the SIP panels.

Asked By Kevin Camfield | Jan 17 17
6 Answers

How to insulate a vaulted ceiling

I am an American living in Provence France. We have hot summers and for the most part mild winters. In January, temperature can drop into the upper twenty during the night. It is a dry climate. I have been renovating a house at different times since last April. During the spring of the year I did the outside roof structure. I installed a new wood decking then a product called flexotuille designed to put under a clay tile roof. After a few other project, I have removed the inside ceiling in the den area in order to vault the ceiling in this area.

Asked By Louis Mattei | Jan 23 17
11 Answers

Insulation for vaulted ceiling

We re-roofed our house this summer and found a lot of damage over our family room with a vaulted ceiling. We replaced the plywood and are now redoing the underside. The roof has a roof ridge vent and ventilation holes in the soffits. We are creating on-site baffles with 1" rigid foam boards. We are planning to use R30C insulation which is denser for cathedral ceilings. The question is do we use faced or unfaced, and do we need to use plastic sheeting as a vapor barrier? We want to get it right this time!
Thanks,
Kim

Asked By Kim Howard | Nov 22 16
3 Answers

Smoke odor

Hi, We are restoring a severely fire damaged home and while many components have been simply removed (down to the studs), the framing needs to be treated to eliminate the smoke odor. Our research has pointed us toward alcohol based shellacs. Some say first use an oil based primer and then the shellac. Can you advise?
Thanks, jk

Asked By Joseph Klockner | Jan 23 17
1 Answer

Can Roxul Comfortboard 80 be installed on roof deck in non-vented assembly 70psf load requirement?

Passive house build in Northern California

Asked By Forrest Kerr | Jan 14 17
1 Answer

Cold access room - Air barrier gaps between roofline and exterior wall

Hi Everyone,

Asked By Joe Duchek | Jan 13 17
1 Answer

Hydronic radiant heat over concrete slab

I'm building an addition that partly includes an extension for an existing room off one side of my house here in Connecticut. Existing floor is 2 1/4" x 3/4" oak strip hardwood floor. Addition floor will be slab-above-grade with poly and rigid foam underneath the slab. Need to "marry" the existing oak floor (conventional wood subfloor/structure) to new concrete slab using new oak strip flooring. Because I'm building this addition myself, there will be more than sufficient time for the slab to dry (perhaps a year or more) before new finish flooring needs to be installed.

Asked By John Rooney | Jan 14 17
1 Answer

Insulating an historic house's attic

Hi all!

I live in Montgomery County, PA, which is at the northern edge of the 4-A climate zone according to the map on this site.

Asked By Robin Klingsberg | Jan 15 17
9 Answers

Insulation retrofit

Looking for some advice on a smallish rehab project I am about to start. I've read many of the great articles and Q&A discussions here, so I think have bit of direction...but as I am novice, I am interested in some feedback before I moved forward.

Asked By Jeremy Kachejian | Jan 12 17
Register for a free account and join the conversation


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