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!

3 Answers

Here are the facts about this house first;

Asked By Richard Beyer | Aug 29 14
2 Answers

My 1927 house has balloon framing, real plaster walls on rock lath, and no vapor barrier. It has cedar shingles over tar paper. If I blow insulation into the walls, will I create a problem with vapor from the house condensing inside the walls? Even without insulation (current condition), can I close the top of the walls in the attic or will that also allow water vapor to condense in the walls?

Asked By RUTH HENDRICKSON | Aug 29 14
Answers

I understand from prior posts there are concerns with the flash foam and fiberglass insulation in terms of moisture vapor.

Would the use of proper barriers and roxul instead of fiberglass help to abate that concern?

Asked By George Levicki | Aug 29 14
10 Answers

This is something that as passed a few times in my background brain processes,

How does SHG on exterior cladding/glass influence heatloss ??

If glazings specs 50%VT , a part of the remaining 50% must be converted to heat?

If exterior cladding on a building is black, and sun is shinning on the south face,
it must affect the heatloss greatly for the shined on walls ??

As an example, let's assume a building up here cold north.
20c inside 0c outside.
Sun shines on a large flat south wall that was cladded with a black painted steel sheets finish.

Asked By Jin Kazama | Aug 28 14
1 Answer

My new house is designed to limit penetrations through the building envelope to as few as possible. Nevertheless, sillcocks, outside electrical receptacles, outside lights, HRV intake/ exhaust, etc. need to be sealed.
Are there methods or products that are more effective than others? How about ease of installation? I've seen photos of tape covering holes and that seems like a pretty clunky solution. I'm probably going to either do much of the airsealing myself, or at least supervise it.
Thanks for any advice.

Asked By stephen sheehy | Aug 29 14
3 Answers

I keep hearing the term "acoustical sealant" in the context of air sealing, as in "use acoustical sealant for air sealing because it remains flexible", but am a little bit confused as to what it means. Does it refer to:

  1. Tremco accoustical sealant, the specific product?
  2. Any caulk or other sealant that exhibits the "remains flexible forever" property?
  3. Something else entirely?
Asked By Aaron Birkland | Aug 29 14
20 Answers

We are building a straw-bale house with steel bones in Sacramento, CA in spring 2015 and I'd love to get some insights from the community! We are pretty far along into the design process, but with nothing purchased as of yet I'd love to get some input before we put our money where our mouths are.

Our goal is to have a (mostly) passively heated and cooled home in (relativity) temperate Sacramento, CA. Passivhaus would be nice but it's an aspiration rather than a goal. Our lot has a number of trees for shade that we plan to utilize, especially in the western aspect.

Asked By Nick Campbell | Aug 26 14
19 Answers

I was speaking with my passive house consultant the other week, and she expressed concerns about boring critters and subsurface rigid insulation. She had such an experience with some insulation in her garden (It was put in one season and removed at a later time as she got back to completing the project.)
Now, I know all about the ate/termite protection used in these insulation products, but what about larger critters that would love to have a warm dry home?

Asked By Steve Young | Aug 16 14
15 Answers

I would like to ask the math pros here on how to calculate heat loss from infiltration rates.

I have seen so many different formulas in the last weeks that my head is hurting.

So would like to have a "reliable" formula that could be used in my never-ending expanding excel spreadsheets !

Something with at least a little bit of proven precision, that could be used to effectively get additional heat loss using door blower results or planned target value.

Links or straight formula please :)

Asked By Jin Kazama | Aug 25 14
3 Answers

I would like to add foam board to the exterior of my house to beef up the R value. The walls currently are 2x6 with fiberglass batts and plastic sheeting as a vapor barrier between the studs and drywall. Most of the stuff I've seen says you don't want a vapor barrier on the inside so your sheeting can dry to the inside but I haven't found much information on what to do if the vapor barrier is already in place. Thanks!

Asked By Jacob Roark | Aug 28 14
Register for a free account and join the conversation


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