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!

4 Answers

"Innie" Doors?

I'm planning on adding rigid foam insulation to an exterior gut remodel.

I believe I will adding OSB, 2" of foam, 1x4 furring and the fiber composite siding to the existing 2x4 frame wall.

Even if I purchase a 2x6 pre-hung door with a 6-9/16" jamb, it will be short of the new wall. How should I solve this?

In Green building techniques | Asked By Chad Yates | Jul 18 12
12 Answers

Fancy canned spray foam

I see fancy canned foam in the blogs from time to time, with metal triggers and hoses. Where would one buy a setup like this? I'm building my house on weekends and can't seem to reuse cheap canned foam hoses... Maybe there is a trick I don't know about.

In General questions | Asked By stephen edge | Jul 6 12
1 Answer

What is the easiest way to replace the subfloor?

I recently bought a 1970's model mobile home, and its actually in really good condition. Some neighborhood kids broke out the windows in it, and the rain has caused the particleboard subfloor to bow and swell up into big hills throughout the living room, kitchen and hallways. The floor joists are fine. What is the easiest way to rip up the particleboard without damage to walls or framing? There is no ductwork, no insulation, and we need to replace the plumbing anyway so none of that matters. Thank you for any advice, im doing this on my own for the first time and have no idea what im doing.

In General questions | Asked By Angel Jones | Jul 18 12
2 Answers

Roofing Help?

I have a flat roof, 2700 sq foot, single story home that was built in Broward Co. Fl in 1972. Around 1995, the previous owners obviously had some issues and had the roof re-roofed with no tear off (legal to code). What seems to have happened is that the roofers did not enhance or create much of a pitch at that time and my roof pools in particular places, many places. To make matters worse, there is only one drainage area.

In General questions | Asked By Suzi Margolin | Jul 17 12
4 Answers

Rainscreen fastener length

In a rainscreen wall system, is it ideal for siding fasteners to be long enough to pass through siding, furring, sheathing, and still bite into the framing?

3/4" horizontal lumber siding
1x4 vertical furring strips
1" diagonal lumber sheathing
2x6 framing

Thanks for the advice, it's a been hugely helpful.

In Green building techniques | Asked By Richard Baumgarten | Jul 17 12
6 Answers

Correct roof overhang depth for proper solar shading

I used Sketchup to help determine how the solar path would fall on the house I am designing. How do I determine the correct amount of shading/sun?

With the window heights and overhangs I used in the model, at noon on June 21, the entire glazing of the south elevation windows are completely in shadow, but just barely. At noon on January 21, the glass is completely exposed. This seems, intuitively, to be the sweet spot. But should I tweak the overhang to get more shading in the summer months or, conversely, more sun in the winter months?

In General questions | Asked By erik olofsson | Jul 14 12
2 Answers

Conditioning a basement in a superinsulated home?

A lot of talk is about the exterior walls and roofs of superinsulated homes. Also R value is addressed for basements and below slabs. Conditioning of the main floor or above grade is often discussed and minisplits are recommended. However I cannot seem to find too much talk on conditioning a finished basement level for superinsulated homes.

In Mechanicals | Asked By Jesse Lizer | Jul 3 12
8 Answers

Bath fan in an airtight home

How do you reconcile leaky bath fan ducting within an airtight new home?

In General questions | Asked By erik olofsson | Jul 5 12
13 Answers

Insulating HVAC ducts

I have a feeling this is a dumb question -- but I don't get it:

Nearly every house in heat-pump-land has ductwork in the attic ... insulated to R-6 or R-8. Sure, it should be in conditioned space, but for millions of structures it isn't.

Why aren't there products that offer thicker insulation for attic ducts? Or conversations about DIY ways to improve R-value?

What happens if someone adds a couple of layers? Or wraps ducts in wall batts?

In Mechanicals | Asked By JoeW N GA Zone 3A | Jul 7 12
5 Answers

Is a 1/4 gap in rainscreen enough?

Your advice and articles are topnotch. I wish I had been reading them before now. Thank you in advance for your help. I am renovating the east wall of my home in northern Vermont. For the past two months the wall has sat- OSB covered with Tyvek. I plan to side this wall with fiber-cement clapboards to match the rest of my house. The OSB is there and the windows are well-flashed, so I would rather not mess with them. I see that many sources recommend a 3/8 in. air gap in the rainscreen. If I do this I must reflash my windows. Do you think a 1/4 in. gap is adequate?

In Plans Review | Asked By Jeff Grogan | Jul 12 12
Register for a free account and join the conversation

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