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9 Answers

Following up on the musty smell in our crawl space

Editor's note: This is a follow-up to a previous thread on GBA. The previous thread was Why do I have a musty mildew type smell in my conditioned crawl space?

Asked By Linda Larochelle | Aug 26 16
8 Answers

How much are mini-splits really affected by altitude?

Hello -

I'm sizing a heat pump mini-split for my 20x20 garage, which has been pretty well air sealed and insulated with closed cell foam. I've had a series of installers out and the recommendations were all over the place, ranging from 12k to 18k BTU, and from $3k to $12k.

Two of the companies actually bothered to do a load calculation, and I tried it online as well - but those numbers had a broad range, too.

Asked By Dave H | Sep 22 16
2 Answers

Condensation on plexiglass?


In fall-winter-spring, I have lots of condensation on my double-pane windows. After reading multiple sources on the Internet stating that condensation does not form on acrylic, I fastened a plexiglass sheet on a window to test. I lowered the double-cell cellular shades for the night.

This morning, I realized that the test failed - there was fogging on the bottom part (but no droplets). I guess I read the wrong sources or I did something wrong.

Which one is it?

Thanks for your help!

Asked By Marc Delisle | Sep 25 16
0 Answers

Rain screen detail on chimney box with brick veneer and flashing detail

Building chimney box on peak of roof for chimney pipe and plumbing vent to exit. Thin brick veneer with a rain screen detail. The lid for the chimney box is elevated 1/2" for an air gap with 3.5" down turned legs for weather protection. All good so far, but when I go to install the step flashing on the roof next to the brick and then the cap flashing over that which it's mortared into the grout line, there is now no more ventilation from the bottom of the rain screen as it has been sealed off with the flashing details.

Is this an issue?

Asked By eric Mikkelsen | Sep 24 16
7 Answers

Best insulation method for LP Smartside panels as sheathing & siding?

Building woodshop in cold 6-7. Using LP Smart side panels as sheathing and the siding. 190 series, product is .53" thick.

Concerned about condensation on interior side of this sheathing/siding in cold weather. Will dense pack cellulose be fine, or should this siding/sheathing be first sprayed with 2lb closed cell foam?

Asked By eric Mikkelsen | Sep 4 16
6 Answers

Why is mold/mildew growing behind my rigid foam?

So I had started to finish my basement area and read all of the articles on GBA. I was using 2'' of XPS foam on the cinder block walls and recently had to remove a bunch to access an area for the egress window. When I pulled it off, I was surprised and scared to see that I had black stuff growing on the cinder block. I don't know if it's mold or mildew, but it can't be good, right? You can even see how it's growing around the foam adhesive that I used to attach it to the wall.

Asked By Jay Johnson | Sep 21 16
1 Answer

Manufactured stone veneer

I know this is not really a green building question, but I am looking for a copy of the MVMA installation instructions, First edition. I have later versions, but was hoping to find the original version. Thanks.

Asked By Mark Reinmiller | Sep 22 16
10 Answers

ZIP system R-sheathing on a Roof

I'm looking for a poor-man's alternative to thick polyiso on a roof and was wondering why ZIP system R-sheathing is not "allowed" to be on a roof? From Huber's web site:

"Zip System R‐Sheathing is currently limited to wood‐framed wall applications only. DO NOT use roofs or light gauge metal framing. For systems requiring multiple layers of water‐resistive barriers, ZIP System R‐Sheathing is intended to replace only the first."

My roof is extremely unique and you will all probably roll your eyes, but here we go:

1. My Roof is vented with baffles

Asked By Christiaan Lutzer | Sep 20 16
4 Answers

Converting a flat roof to a pitched roof?

I'm in the process of remodeling my 1950s ranch house. I have a modified bitumen flat roof, which is about 15 years old. The roof is in okay shape right now, however it's sloped incorrectly in about half the roof and has some ponding of a few inches most of the time. There has been some damage to the roof sheathing near the chimney in the past. The rest looks to be in good shape. I'd like to improve the roof and be able to add more insulation to the ceiling as the first part of my renovation. I'd like to get your opinions on the best way to improve the roof.

Asked By Betina Chaon | Sep 20 16
21 Answers

Can kneewall polyiso boards be left exposed on the attic side?

Can kneewall polyiso boards be left exposed on the attic side?

Asked By John Sean | Sep 16 16
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