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!

13 Answers

How to get the best out of a thermal imaging visit

I have a contractor coming around in a few days to do thermal imaging on our house with and without a blower. He's going to visit at 6am so we should have at least 10C difference between inside and outside and no direct sun since the day before.

In Energy efficiency and durability | Asked By David Coote | Oct 22 12
3 Answers

House tightness

Is there any thing in the code (North Carolina) that states the ventilation, natural or mechanical, is at an acceptable rate. I have ran a blower door test on a new residential and got 867 cfm50 with 2.95 ACH50.

I don't think that there is any thing in the code but I want to make sure that the house is safe regardless of the code requirements.

In Building Code Questions | Asked By Matt Edwards | Oct 29 12
3 Answers

Outside Combustion Air

My daughter has an 1860's vintage house in New Bedford, MA with a hot air heating system. She has a damp and moldy basement which supplies the intake air for furnace. Can we easily install outside intake air to supply return duct and does it need any special equip. besides a vent hood and duct? Would it replace the damper attached to return duct? She has a new baby and a 4 year old and we are concerned about moldy air being sent to living space.

Thank you


In Energy efficiency and durability | Asked By Fletcher Hall | Oct 29 12
3 Answers

Can cellulose be too fluffy?

During one of my frequent visits to this area of the site, one of the discussions revolved around, to quote Martin "the slight performance degradation of very fluffy insulation on the attic floor due to wind-washing and internal convection currents, especially in very fluffy fiberglass insulation at very cold temperatures". My question comes from my recent experience of removing my cellulose insulation and blowing it back in after spraying ccSPF on the attic floor. The re-used cellulose insulation seemed much fluffier than the supplemental cellulose I installed.

In Energy efficiency and durability | Asked By Pete Marthaler - Zone 7 | Oct 30 12
8 Answers

Hurricane Sandy reports

East coast readers: what's happening where you live? Has the storm arrived?

Here in northern Vermont, as of 10:30 a.m. Monday, we haven't had any rain yet.

In General questions | Asked By Martin Holladay | Oct 29 12
1 Answer

Bathroom remodeling & insulation

Two questions on insulating exterior wall of tub/shower area. I am in northern Pennsylvania.
Currenlty the wall has hardboard siding and sheathing that is not vapor resistant, the rest is stripped down to the studs. I plan on adding fiberglass, then 6-mil poly, then cement board, and tile.

Is this method appropriate for the area i live in?

In Building Code Questions | Asked By eugene sanchez | Oct 29 12
1 Answer

Proper ratio for attic venting?

We have a very simple gable roof with flat ceiling that requires venting. the code says the unobstructed vent area shall not be less than 1/300 of the insulated ceiling area. The vents must also be evenly distributed on both sides of the house with not less than 25% of the required openings located at the top of the space and not less than 25% at the bottom.

In General questions | Asked By erik olofsson | Oct 29 12
2 Answers

Most efficient way to supplement existing solar batch heater in winter?

I'm a tenant in a yurt in east San Diego county CA, at around 4000 ft. of elevation. Right now, the only hot water comes from a solar batch heater, which completely meets my needs April-October, and intermittently on clear days throughout the winter months. However, the landlord has agreed to install something to provide consistent hot water to the one indoor sink and the outdoor shower.

In Energy efficiency and durability | Asked By Ben Blue | Oct 29 12
5 Answers

Ice & water UNDER or OVER the drip edge?

I did a little searching before asking this, thinking that the topic
*must* have come up in the past, but didn't find anything coherent.
We're having this bit of disagreement between a GC and a roofer as
to whether ice & water shield over decking should flash over or
under the drip-edge piece at the connection to the fascia. The
roofer's claiming that putting the drip-edge metal over the I&W
isn't a reverse flash because water in an ice-dam situation would
flow upward, and the GC [who I'm tending to agree with] points out

In Energy efficiency and durability | Asked By Hobbit _ | Oct 26 12
4 Answers

100 year old house--insulation for exterior walls/ceiling

We're gutting a 6x15 area, originally a pantry, to add a tiny powder room and walk thru pantry. The exterior sidewalls are 3/4" pine boards with redwood clapboards. About 15 years ago we stripped the claps, used oil based primer and 2 coats of high quality latex paint. There is no housewrap, but some red rosin paper under the claps. The roof is sound with no leaks.

In Energy efficiency and durability | Asked By Jo Swearingen | Oct 29 12
Register for a free account and join the conversation

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