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!

6 Answers

I have read several articles about how much and which kind of insulation to use which is just confusing me. I will be building a house near Montgomery,Alabama in appox. 4 years and I know things are changing all the time. Some people say the best insulation is the sprayed which I guess is right because it covers all the holes. Would 2x4 frame house with sprayed foam be enough insulation? Do need rigid foam? I plan on having crawl space with concrete floor. On the blogs there was section by Matt Risinger, what do you think about his ideas on insulation?

In Energy efficiency and durability | Asked By William Wingett | Nov 1 11
2 Answers

I am looking for specific information about detailing plumbing waste lines for a slab on grade on Cape Ann (north of Boston, Zone 5A). I am concerned about sub-slab insulation, the air barrier, vapor barrier and general coordination of excavation, concrete and plumbing trades. I am familiar with Building Science Corporation's recommendations for polyethylene location and "no fines" in the stone layer.

Thank you,
John Rockwell
Rockport, MA

In Green building techniques | Asked By John Rockwell | Nov 8 11
26 Answers

We are building a new home ourselves and are looking for a checklist to help us prepare for the blower door test.

In General questions | Asked By Frank Willingham | Sep 25 11
18 Answers

Having looked at a variety of foundation systems, I see problems with all of them. Any stem wall or thickened edge generates insulating or compacting/pouring issues, as far as I can see, especially w/ lots of foam underneath. This one is not perfect, either. Nevertheless, here is an option I thought of that gives you the rigidity of the thickened-edge slab but is easier to insulate... except at the garage door. It also better locks the house to Terra Firma than a SOG, should there be seismic activity, .... I think it does, anyway. This generates a 4" lip to drive or step over.

In Plans Review | Asked By John Klingel | Nov 3 11
2 Answers

I'm insulating an existing basement slab using rigid foam and a dimpled mat.

In General questions | Asked By Ben Johnson | Nov 5 11
5 Answers

Greetings. I am in the process of "rescuing through renovation" a 1905 vintage 2-1/2 story house in Omaha (zone 5) that was formerly divided into seven apartments. Being that the house was used for apartments for the last 50 years, it has received minimal maintenance. The weak condition of plaster on the inside of the exterior walls have made the decision to gut the walls of plaster and lath a clear choice. I have new windows on order to replace the existing deteriorated windows.

In Energy efficiency and durability | Asked By Richard Ryker | Nov 5 11
37 Answers

We have a SIP roof that will be covered with standing seam metal. Because the lumber between SIPs roof panels present thermal bridges, we wanted to add two inches of EPS to break it.

Now the question is how to put the assembly together. We already have High Temp underlayment on the SIPs panels. Can we put the EPS on top and install the metal roofing on top of that?

Or do we need to put EPS, add another layer of plywood (or furring), underlayment and then the metal roof?

In Green building techniques | Asked By Roger Lin | Nov 1 11

I am not a professional, but designed and installed my own ground-based heat pump system.

In GBA Pro help | Asked By paul willing | Nov 5 11
5 Answers

I have 2x10 rafters with a new roof. Can I use Demilec AgriBalance open-cell spray foam?

They tell me it has an R-value of 4.5. My main concern is using 3/4" tongue-and-groove pine for the ceiling. Should I use a vapor barrier or not? Thinking of using CertainTeed MemBrain. Do not want mold issues.

Thank you for any input.

In Energy efficiency and durability | Asked By jim cassidy | Nov 2 11

I recently encapsulated my crawlspace (in central Maryland). Now it's time to insulate. We want to incorporate rigid mineral wool- Roxul's RockBoard 60, to be specific. The heavy vapor barrier, a DrySpace product, goes all the way up the interior foundation walls and stops just a few inches shy of the sill for future termite inspections. If I want to insulate these interior walls with RockBoard, what is the best approach? I ask because it seems few builders have much experience with this material..particularly in this application.

In General questions | Asked By Michael Matthews | Nov 4 11
Register for a free account and join the conversation

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