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

[Click map to enlarge]

drawing of climate zone map.gif

Advice can depend on climate -- Please specify in your question.

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!

Ask a Question >
3 Answers
How did you connect the heat pump to the ventilation system?

I am building my own home in central Maine using a double studded wall with 8" of Thermax between the studs. My heating contractor says I can't connect the heat pump to the ventilation system.

- art

In PassivHaus | Asked By Arthur Taylor | Nov 24 13
3 Answers
HRV help!

We are building a 2600-2700 sq ft home in VT.
Using spray foam insulation.
Told we need HRV ...
We do not know much about the various systems but with our open floor plan are having
a difficult time with duct work/vents - not many walls to put them in.
1. Are there any systems that hands down work better
2. Aret there any systems that use smaller or minimal duct work?
3. Any particular HRV systems to avoid? Think FanTech is what is spec'd.
Thanks!

In General questions | Asked By Elizabeth Croes | Oct 19 13
19 Answers
Insulating wood I-joists with Roxul

O.K., to repeat, I'm building a 1-story house in Zone 4C. Builder is using wood I-joists 16" O.C. for the floor. After considerable thought and reading, including comments by Dana Dorsett and research by Washington State University, I decided that an open crawl space would work for me. However, I have insisted that we use good insulation: R-24 (commercial size) stone wool batts by Roxul for the floor insulation. This comes in 16.25" widths. My builder says, Fine, but how are we going to shove them past the flanges at the top of the I-joist so that they're snug against the floor?

In Energy efficiency and durability | Asked By Gordon Taylor | Nov 21 13
5 Answers
Our water heater needs to be replaced and we are considering getting a heat-pump water heater

Our water heater needs to be replaced and we are considering getting a heat-pump water heater. We could really use some advice as to whether or not this makes sense for us.

Our current water heater is still under warranty, allowing us to replace it with a 5 year unit (current unit is a GE 40 gallon natural gas-powered tank). We are a family of two adults and one 3 year old. We could get $1,050 rebate if we bought one before the end of the year.

Other details:

Therm cost: current month 88.1¢, last month $1.36

Klw cost: current month 10.3¢, last month 10.5¢

In Mechanicals | Asked By Leah Marshquist | Nov 25 13
4 Answers
One more cold sheathing question

I see that cold sheathing issue has been thoroughly discussed, including an excellent Martin's article. The takeaway I got (right or wrong) is "eliminate air infiltration, allow wall to dry at least in one direction and don't worry". This is happening in Northern Virginia, ASHRAE Zone 4, 111 days with freezing temperature a year on average. House was built in 1986.

In General questions | Asked By Vladyslav Ovchynnikov | Nov 25 13
5 Answers
I need some help (advice on windows)

I'm in the process of building a new house. I am zone 6, I have the house orientated with lots of glazing on the south side.Trying to gain as much heat from the sun as possible. But i don't want to get cooked in the summer. I have external shading designed on that side. I have a R-20 under my slab, R-30 on my foundation walls, R-40 walls, and a R-60 cap. I am shooting for a .6 ACH at 50 pascals or less.

In PassivHaus | Asked By Kirk Nygren | Nov 21 13
3 Answers
Is it necessary to use a rainscreen when installing fiber cement siding over Zip wall sheathing?

I am trying to keep the budget down on the siding install on my own home

In General questions | Asked By Richard Shea | Nov 24 13
7 Answers
Why don't we use plastic as a barrier between the ceiling and a vented attic?

I have been thinking about this. Why couldn't a builder staple a 2' x the length of the top plate piece of plastic to the top plates of the walls before the rafters are set? This piece could then hang down a foot on either side of the wall and still leave the ceiling open for electrical. Then, once its time to close up the ceiling, you could poly the whole ceiling and have an ample piece next to every wall to tie into and gett a good tape seal on. It seems like this could be much more efficient than using plywood/osb for an air barrier.

In Green building techniques | Asked By ben grzadzielewski | Nov 24 13
3 Answers
Notable quote on building cost

In the current issue of FHB (Jan 2014, No.240), there is an article by Steve Baczek on page 50 called "Designed for Success," part one of "The Passive House Build." At the end of the article the author makes a very nicely worded statement about the cost issue associated with Passive Houses, which can be applied also to the PGH level of house. I thought it worthwhile to draw attention to the statement as a "notable quote of the week."

In Energy efficiency and durability | Asked By Dick Russell | Nov 24 13
3 Answers
How long to wait before painting spray foam insulation with fire retardant paint?

We are general contractors and sub out the spray foam insulation jobs. Some contractors paint the fire retardant on right away and others say they have to wait a day and thus come back to the job later to paint. I'm trying to find out which is actually right. Do you have to wait 24 hours to paint the foam or not?

Thanks,
N

In General questions | Asked By Nancy Tang | Nov 25 13
Register for a free account and join the conversation


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