Q&A: A Forum for Green Building Experts and Beginners

Q & A Instructions

[Click map to enlarge]

The GBAGreenBuildingAdvisor.com web site has a wealth of articles on a wide variety of construction topics. Before posting your question, you may want to check out the articles on this page: How To Do Everything. You just might discover an article there that provides the information you seek.

Please register for a free account or sign in to ask and answer green building questions.

If you want to post a question, 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!


5 Answers

Most resilient or maintainable air-sealing approach?

I'm in Austin TX, where the soils are expansive clay. This means that as the soils expand and contract with different moisture levels the foundation and walls move a fair amount. This is particularly true for wooden pier and beam construction but also for slab based construction.

I realize that one option is to attempt to control movement by "watering" the foundations and an advance version of that would be to monitor the water content and attempt to maintain it at a near constant level. This is costly, both in materials and in water (but might be advisable).

In Green building techniques | Asked By James Howison | Dec 9 13
8 Answers

Why is "reflective insulation" still being sold by HD and Lowes -- and used by many contractors?

I stopped by my local HD for more supplies and was surprised to see rolls of "radiant barrier" bubble wrap on the shelf. Lowes and online vendors sell products with similar claims. For example, here are the benefits promised by a leading vendor:

"An easy-to-install double reflective, double bubble insulation

R-values range from R-3.7 to R-21 depending on the applications

Energy-saving residential applications include: cathedral ceiling, crawl space, radiant floor,
wall, HVAC duct, water pipe, garage door, knee wall..."

In Energy efficiency and durability | Asked By Mark Hays | Dec 6 13
6 Answers

Looking for comments on this wall assembly

Hey everybody.

I want to build a Pretty Good House in the southwest in zone 2. It's a cooling-dominated climate, very dry, but there is a rainy season from mid-July to mid-September where it can get pretty sticky. Overall, we only get 11 inches of rain a year.

So, I've been thinking my way through numerous wall assemblies with the help of GBA.

I've read:
http://www.greenbuildingadvisor.com/blogs/dept/musings/hot-climate-design
http://www.greenbuildingadvisor.com/blogs/dept/musings/airtight-wall-and...

In Green building techniques | Asked By Michael McNulty | Dec 9 13
3 Answers

Best ventilation purifying system?

Hi! We live in Mt. Vernon, NY. Our basement is plagued by a bad odor that sits at the top of the stairs. The basement is damp and we have containers of DampRid. Also, we have moving boxes (from a moving company) stacked up down there and we're afraid that something noxious is coming from them as well so I'm trying to empty them as fast as I can.

We're looking at different systems and have seen the Wave Home Solutions and the Aprilaire websites. Do you have any suggestions for which system to use and who to have install once we decide?

Thanks so much
Erica

In Energy efficiency and durability | Asked By Erica Heymann | Dec 10 13
7 Answers

Insulation and vapor barrier with tongue and groove

I am in Southern Indiana which is zone 4a. My wall is this from outside in...Hardie board lap siding, house wrap, 7/16 OSB. That's where I am now. I have 2x4 walls.
If money were no object I would do 3 1/2 inches of closed cell foam. 2nd choice would be and inch or so of closed cell on the OSB and then net the walls and use cellulose. Even an inch of foam is very expensive so the cheap option is netting the walls and blowing in 3 1/2 inches of cellulose.

In Energy efficiency and durability | Asked By Mitch Groves | Dec 8 13
2 Answers

Insulation and ice dams

We are getting ice dams on the south and west sides of our home. We have plenty of insulation in the attic but on those two sides (south and west) there is a covered porch. There is no insulation on the soffit that covers the porch and of course no insulation in the eaves.

The porch is about 6 feet wide and runs the entire length of the south side of the home (the front) and the entire length of the west side. The east and north sides only have eaves which are less than 12 inches.

In GBA Pro help | Asked By Jared Bennett | Dec 9 13
1 Answer

I have an ICF house on Vancouver Island with a Open Joist/ T&G Fir roof

The T&G Fir is attached to the open joist through the T&G Fir, above the T&G is a layer of Glued Blue Skin followed by 3 layers of High density foam boards (8*4) 3.25x2 with 1x1..25 cross layered there is 5/8 Ply screwdown with long screws to the joists, The tar paper and duroid roofing is attached in the normal manner.
When we moved in (3 years ago) no issues materialised but where the T&G extends over the wall (outside) we are now seeing evidence of condensation when the temperature drops arond 0c. I suspect the T&G has dryed out and shrunk over time

In Energy efficiency and durability | Asked By Alan Webb | Dec 9 13
1 Answer

How to deal with odor coming up from basement?

I live in Nova Scotia. Moderately hot and sometimes fairly humid summers, cold winters although very variable. Similar to US North East.

In Energy efficiency and durability | Asked By David Monaghan | Dec 8 13
3 Answers

Obscure OSB air barrier questions

In general, is an air barrier composed of 7/16" OSB similarly effective as a 5/8" OSB air barrier, assuming all installation details were the same for both?

I have seen people using caulk and without caulk when fastening OSB to structural lumber, I assume that the concept with the caulk is that they're trying to seal the penetrations through the OSB?

Are the air leakage through holes created (and filled) a significant source of air leakage?

Thanks,

Chris

In Energy efficiency and durability | Asked By Chris Barnes | Dec 9 13
1 Answer

OSB vs. Zip System

Quite often I here about the problems with osb and moisture. It holds moisture, it falls apart, etc... Does this apply to zipsystem sheets or does the coating and glues they use put it in a different category? I have had to replace failed/rotted osb in the past and I switched to zip system because I was told this would not happen. Is this true???

In Green building techniques | Asked By darren williams | Dec 9 13
Register for a free account and join the conversation


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