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

[Click map to enlarge]

drawing of climate zone map.gif

Advice can depend on climate -- Please specify in your question.

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!

Ask a Question >
1 Answer
Insulating a 1-1/2 Story House

I am about to begin construction on a house in central North Carolina. It is a basic rectangular gable roofed story and a half with dormers on the front. Due to the design of the house it will have the HVAC for the second floor in the attic. This obviously means I will need a sealed/conditioned attic. I do not want to use spray foam in the attic because I feel there are too many unknowns with it. I believe cellulose is the best way to go but do want to maintain an airspace in case of a roof leak that always seems to occur at some point.

In Energy efficiency and durability | Asked By Andrew Smith | Apr 24 10
3 Answers
What's the best WRB option when using foam to insulate your structure / sheathing?

I'm most concerned about the critical details around windows. I plan to use OSB or plywood sheathing coated with StoGuard as the building's air barrier. This will be covered by Tyvek Drainwrap, followed by two layers of taped foam insulation (XPS or Polyiso). Finally, I'll have an airgap between the foam and siding (i.e. furred fiber cement). What is the safest option for windows: 1) Use Drainwrap as WRB, flash windows to wrap, then use exterior trim? 2) Use foam as WRB, extend window box flush with foam, install and flash flanged windows to foam?

In Energy efficiency and durability | Asked By Daniel Ernst | Apr 24 10
3 Answers
How do I build a wall within an exterior wall to add insulation value?

I want to at least double the insulation value of my exterior walls(existing). Do I have to rip out the drywall completly or just bust through it in a lot of places. The existing wall has no vapor barrier on the inside or tyvec on the outside. Its just a 2x4 wall with 3 1/2 " bats and 3/4" dow board insulation on the exterior and vinyl siding. I plan to put a vaper barrier in when I build the wall. Was thinking of another 2x4 wall off set from the existing studs giving me an 8" plus wall, depending on the gap between. Any thoughts? Thanks!

In Energy efficiency and durability | Asked By Chuck Byfield | Apr 25 10
8 Answers
Is foam insulation vulnerable to tunneling insects like carpenter ants?

I understand the clear advantages of foam insulation But I have found situations where it became a home for carpenter ants.This makes me wonder about the wisdom of using it in a semi-structural way on exterior walls,as in supporting siding that is fastened through the foam into solid wood.

In Energy efficiency and durability | Asked By Brian Carter | Apr 18 10
32 Answers
Plywood versus OSB for exterior walls?

I am planning an addition to my house which will have a 500ft basement with 2 floors above it. The exterior walls are 16 ft by 22 ft. The basement will be concrete, and will have brick cladding for the above grade portion (as an aside, the single layer of brick cladding has no gap but is directly applied with mortar to the concrete - what do youthink of that?). The first and second floor will have stucco cladding.

In Green building techniques | Asked By richard Ugarte | Mar 21 10
4 Answers
Tech Shield - Any Trouble with Shingle Warranties or Wifi Reception?

I thought these issues with the foil-faced (for radiant barrier) roof decking were resolved, but I heard a prominent and revered moisture and roofing consultant insist that the major composition shingle manufacturers still will not honor or issue warranties for their products installed on foil-faced roof decking. Is this true? He went on to say that there was also a problem of radio frequency interference or Wifi reception for anyone living under a foil-faced roof deck. I haven't seen any documentation on this alleged problem. Does anyone have any experience on either or both of these issues?

In Green products and materials | Asked By Stephen Colley | Apr 21 10
2 Answers
Blown in Cellulose or Batts in Vaulted Ceiling / Scissor truss

I've been advised against blown in cellulose because the pitch is too great and the cellulose will eventually settle from peak ( http://www.flickr.com/photos/48876863@N08/ ). What is the best practice for insulation for this pitch?

In Energy efficiency and durability | Asked By Frank | Apr 22 10
6 Answers
Residential flat roof design

Hi,

I'm an architect looking for advice as to how to detail a wood frame, flat roof/parapet wall assembly. I looked for one on this website and there isn't one. By flat I mean, one one that is sloped to drain and either is topped with a built up roof membrane or a single ply membrane. This is located in a mixed climate (Northern California).

I'm tending toward having an unvented assembly as the configuration doesn't lend itself to a simple venting solution. How should I insulate this - fully insulate with fiberglass batts, cellulose, spray foam?

In General questions | Asked By Daniel Weaver | Apr 15 10
2 Answers
Safe flooring option for basement playroom with uneven floor.

We had some water damage in our basement recently and I do not want to replace it with carpet due to the fact that the area is the children playroom. The research I have done so far - I see options as: cork, marmoleum, Flor carpet tiles, natural rubber. I don't want to pay a ton of money - but I want it to be a healthy environment.

In Green products and materials | Asked By Sharon | Apr 21 10
4 Answers
Thermal Eather Storage

Creating one of the most comfortable and economical heating systems available, SmartRooms Earth Thermal Storage System is installed in soil or sand under a concrete slab building foundation. (Sometimes called slab heating.) The result is that the ground underneath becomes an efficient, large mass of stored thermal energy. It's the same principle as the earth's core.

Their entire "energy saving" seems to depend on time of day off peak electrical rates as far as I can tell.
http://www.thermaray.com/solutions/earth.html

Comments?

In Energy efficiency and durability | Asked By Ted Ross | Apr 21 10
Register for a free account and join the conversation


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