Q&A: A Forum for Green Building Experts and Beginners

[Click map to enlarge]

Please register for a free account or sign in to ask and answer green building questions.

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

Freestanding sauna wall construction / insulation

I'm looking to build a free-standing sauna building in a cold, damp area of the Catskill Mountains in NY State. The heated portion will be a 6' x 8' space, fired by a wood-burning stove. Much of the literature about sauna building on the internet suggests using foil-faced fiberglass batts covered by an air barrier. I have a few questions about this approach:

-Will this be sufficient to prevent moisture infiltration into the wall cavities?
-Can fiberglass withstand temps up to 160F?
-What air barrier can withstand temps up to 160F?

In Green building techniques | Asked By Armin Zomorodi | Feb 10 13
4 Answers

Can I heat-harvest my cathedral ceiling internally?

I have an unventilated cathedral ceiling, insulated with 7 cms of rigid foam. I have tested it and found a 1" airspace between the top of the foam and the backs of the slates. Would it be OK to blow air in at the ridge and force it out at the (internal) eaves, to circulate any entrapped heat ?

I have a good mechanical ventilation system, but I still don't want to risk introducing humidity into the ceiling !

I would then install a siphon near the ridge, and pump the hot air down to the basement.

Grateful for any professional wiews on this !

In Energy efficiency and durability | Asked By green villager | Feb 9 13
3 Answers

Employment with a green builder / contractor

I live in Ottawa, Ontario, Canada. I would love to apprentice under (or work for) a Green Builder/Contractor, but I don't know where to look or how to find this type of job. I've completed my first term in the Construction Carpentry (Advanced Housing) program at Algonquin College, where we learned to frame floors, walls & roofs (gable & hip). I'm willing to relocate, if necessary. If anyone has any suggestions or advice, it would be greatly appreciated.

In General questions | Asked By Ron Bishop | Feb 10 13
2 Answers

Hubble heat-pump water heater vs other heat-pump water heaters — Questions

I recently came across the web site for Hubble Water Heaters of New England. They offer a Hubble PBX heat pump water heater model that comes in 50 gallon, 80 gallon and 120 gallon variations. The main feature of this water heater is that it offers a cement (concrete) tank, as opposed to the more common glass tank models. You may have to Google the web site. We are a family of four (two teenagers) in Tennessee in an all electric house. Garage located 50 gallon electric water heater that rarely drops below 48F in the winter.


In Energy efficiency and durability | Asked By Ken Reid | Feb 10 13
7 Answers

Is it OK to sandwich exterior wall sheathing between external foam board and interior flash coat closed cell spray foam?

I am building a new energy efficient home. The builder wants to have the exterior wall pre-fabricated and for structural stability wants to have the 2 x 6 walls sheathed with 1/2" OSB. The exterior wall would then get 1' XPS or polyiso, a Tyvek rain wrap, and then cement board vertical siding.

The interior will receive a 2" flash coat of closed-cell spray foam and the cavity finished with batt insulation.

I don't see a path for moisture to get to the OSB or plywood, but was interested in opinions on this procedure. Thanks for you input

In Green building techniques | Asked By ed kemp | Apr 18 12
9 Answers

Covering exposed rigid foam insulation on foundation

I am building a new house and plan to have 4 inches of ridged foam on the outside from the foundation to the eaves. My question is how to cover the portion that is above grade level, but below the siding?

In Green building techniques | Asked By Eric Heerdt | Feb 7 13
2 Answers

Do unvented cathedral plank ceilings require spray foam?

I am designing the envelope of a 600 sq. ft. house to be built later this year. It has a cathedral ceiling with a few irregularities that would prevent proper venting. I was planning to use cellulose between the rafter bays, insulate on top of the roof sheathing with rigid insulation, and use the airtight drywall approach to keep interior house moisture out of the cellulose. However, my wife and I want to build the house in a cottage style with wood planks on the walls and ceiling.

In General questions | Asked By Eric Matsuzawa | Feb 10 13
1 Answer

How to insulate my uninsulated house?

I live in a house in Kamloops, BC (40c in summer, -20c in winter, dry climate) that was built in the early 1950's. From inside out: Drywall, Foil-backed paper, 2x4 framing, Drywall (local plywood shortage at the time of construction), Tarpaper, Wood siding. There is no insulation in the stud cavities. The exterior is due for replacement, and I would like to add some R value at the time. I have researched PERSIST designs, and think it would work, but have a couple of concerns.

In Green building techniques | Asked By Ben Colver | Feb 9 13
3 Answers

Adding insulation and new ductwork in a Kansas attic

I live in an 1800 sq. ft. 20 year old single story ranch on a slab. I'm located just outside of Kansas City, KS in climate zone 4A. I want to increase the attic insulation, but before doing so, I wanted to improve the duct work in the attic since the builder did a really poor job with both the design and the install.

In General questions | Asked By Roger Marrs | Feb 8 13
10 Answers

ERV Installation

Folks ... just built a new fully enveloped home. Being concerned about air quality, I had an ERV system installed. We have dedicated stale air exhaust but the fresh air intake is plumbed into the Air handler return. When the ERV runs, the fresh air seems to be coming out of the return filter and not the existing supply side ducting. I would prefer not to have to run the air handler fan all the time. Anyone else experience this issue ?


In Mechanicals | Asked By Johnny Hodges | Feb 9 13
Register for a free account and join the conversation

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