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!

1 Answer

Covering Paint with Non-VOC Paint?

My painter used regular paint instead of the no-voc product we picked. Is it worth having him cover it with the no-voc paint? Or is it better to just leave it as is. Given that "no-voc" paint probably still has some VOCs, we don't want to add more VOCs unless it would provide some type of sealing benefit over the VOC paint. thanks

In General questions | Asked By Brian Jackson | Mar 28 12
1 Answer

Redwood siding corrodes building paper?

I recently moved into a redwood-sided house built ca. 1992 in climate area 5A (midwest). I have have problems with leaking roofs - i thought - until the roofer took off some of the siding below an area where two parts of the house come together - to find that the building paper was corroded, the sheathing completely rotten, and studs and sill plate partially rotten too.

In GBA Pro help | Asked By Katie Grigg | Mar 28 12
7 Answers

Pier foundation - how much space would the plumber, HVAC people prefer?

We will be building a house for my brother in Upstate SC next year. We are currently in the design phase and having a disagreement on where to put the downstairs kitchen and bathroom with the plumbing lines.

I am thinking along the lines of what makes the house the most resilient and easiest to repair and who knows what he is thinking. The house will be on a pier foundation because it is near a flood zone. The land is sloped so that the piers at the driveway side will allow a crawl space of 3 feet or so and probably 6 feet at the other end near the pond and the flood zone.

In General questions | Asked By Lucy Foxworth | Mar 26 12
5 Answers

Website improvements

GBA is working on some website improvements, and we're encountering a few glitches on the way to a better future.

Today's problem includes the occasional blank line that appears (unwanted) in the middle of a sentence, usually after a glossary term. We're working on fixing the glitch.

Please bear with us as our team works on solving this software code problem. And if you want to draw our attention to any other irritating glitches, please do -- by posting a comment here, or by e-mailing me:
martin [at] greenbuildingadvisor [dot] com


In General questions | Asked By Martin Holladay | Mar 6 12
2 Answers

Is it worth the effort? Attic insulation detailing.

My home is a 1950, 2 floor, brick colonial in the Detroit area (5A). This place was built with no wall insulation. There is still no wall insulation.

In Energy efficiency and durability | Asked By GARY ZIRULNIK | Mar 26 12
1 Answer

Thermal Bridging of I-Joists

Building living space over a garage (zone 5-Colorado).
Floor will be 12" I-Joists (3/8 web) with blown cellulose (R-42).
Roof will be 12" I-Joists with blown Cellulose (R-42) plus 2' foam (R14).

Given that the delta T (garage to Living) is only about 40 degrees, do I need to worry about thermal bridging with R-42?

Second question: Have seen a couple double wall projects where the inspectors required 3/4 plywood fire stop every ten feet. Wouldn't this diminish the advantage of double wall?

In Energy efficiency and durability | Asked By Richard Patterman | Mar 26 12
2 Answers

Mass. glazing requirements for school buildings impede energy efficiency

It appears that Massachusetts now requires low solar heat gain (below 0.4) for windows in school buildings constructed with state aid:


The SGHC must be no higher than 0.4, according to page 186 of this document.

In Building Code Questions | Asked By rich cowen | Mar 25 12
3 Answers

I have three energy reduction measures.

Electricity is the only energy power.
One measure saves 25% . The second saves 7.5% and the last one saves 10%. What is the total saving?

In Energy efficiency and durability | Asked By Hanan Waizman | Mar 25 12
0 Answers

A Treehugger blog comments on a GBA story

Lloyd Alter of Treehugger.com has posted a blog commenting on a GBA news story about the Passivhaus petition: A Plague On Both Their Passive Houses.

In PassivHaus | Asked By Martin Holladay | Mar 26 12
2 Answers

Putting insulation in a wall that has none

Just moved into a new (to me) home in Southern California. A single family house, built 1965. I'm relatively new to DIY home improvements but fairly ambitious. I decided to work on upgrading a bathroom and started by tearing down the tub/shower wall in an upstairs bathroom. I got everything out to the bare studs and noticed there is no insulation. I see a thin black paper-like material that is breaking apart and behind that is (what I think) is concrete, then it must be the exterior stucco or something. So, before I build the wall back up, can/should I put insulation in this wall?

In Energy efficiency and durability | Asked By Newman Yen | Mar 25 12
Register for a free account and join the conversation

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