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6 Answers

Green roofs: what's the verdict?

I'm intrigued by the idea but see several obvious problems: 1) leaks, 2) expense, 3) maintenance (weeding etc.), as well as a less tangible but possibly significant issue: 4) prospective home buyers viewing a green roof as a liability (we plan to be in the house for a long time, but plans can change.)

In General questions | Asked By Ray Sten | Feb 14 13
1 Answer

To rainscreen or not to rainscreen?

Hello GBAers,

I'm building a small (250 sq. ft.) cottage in my backyard in the Bay Area in California in climate zone 3C. We plan on using stucco for the exterior as it will match the main house.

The cottage will have one-foot overhangs because it's near the property line. Code around here is two layers of Grade D building paper under the stucco, but I know a lot of you guys believe it's better to add a rainscreen between the paper and the stucco.

In my research, it seems that a lot of the rain screen products are insanely expensive.

In General questions | Asked By Nick Jensen | Feb 19 13
5 Answers

HRV duct penetration

I've got a bit of a condensation problem with a cold-air duct. It's
the fresh-air intake for the HRV, made from a big PVC pipe [for less
thermal bridging than metal] run through a wall and air-sealed
around where it passes through the inner and outer wall layers.
It connects to a piece of insulated flex-duct that runs to the HRV,
with the fiberglass blanket and outer cladding of the flex pushed
right up against the inner surface of the wall to try and expose
none of the cold parts to the inside.

The fiberglass is at the heart of the problem: interior air appears

In Green building techniques | Asked By Hobbit _ | Feb 15 13
5 Answers

Reverse air conditioning?

We live near the Pacific Ocean, where the climate is cool (average about 60-65) year-round. In locations where the sunlight is unfiltered, the light can be quite intense and create a lot of heat. So on a normal day, our attic can be extremely hot--over 100--while the house remains very chilly. Because we have good insulation in the attic, that heat does not come into the house.

It seems to me that there should be a way to pull that daytime attic heat (the attic is very clean) down into the house, but I have not been able to find out how to do that.

Any ideas?

In Energy efficiency and durability | Asked By Maureen Girard | Feb 14 13
9 Answers

When insulating attic rafters, should they be completely filled or should there be room left for air movement?

Attic is finished room, had water damage from use dams, old insulation did not fill rafter completely

In Green building techniques | Asked By Paul Elvord | Feb 16 13
4 Answers

Best exterior foam 2x4 wall and 1/2-inch sheathing system

Looking for some comments on the best way to insulate my addition with the highest R-value possible for my situation and climate area (in New England).

In Energy efficiency and durability | Asked By William Campbell | Feb 17 13
5 Answers

Do I need to insulate duct work that is inside the envelope?

I am considering adding a geothermal heating system to my house in South Jersey. The utility room is inside the house. The trunk and duct work branches are very short and they will be inside the envelope in soffits, pretty much as detailed in "Keeping Ducts Indoors." I plan to seal the trunk and branches with mastic. Do I need to insulate them as well? Is it better to insulate the soffit or the duct?

In Mechanicals | Asked By Michael Arnold | Feb 17 13
8 Answers

Foam sheathing & spray foam

I am an engineer working on a set of plans for a new house for me & my family.

The structure will be located in the Northern edge of Zone 4A.

In Energy efficiency and durability | Asked By Brook Tarr | Feb 16 13
5 Answers

Cedar tongue and groove on walls - Remove or not?

Some contractors have recommended that we take off the drywall and remove the tongue and groove cedar under the drywall (some of the drywall is rotten/black mold) to lay in insulation and put in a vapor barrier. But we are wondering if it would be better to leave the cedar in place and blow-in insulation and then just patch-fix the drywall. We are also replacing windows during this process, and the house is empty.


What should we do?

In Energy efficiency and durability | Asked By Christine Clapp | Feb 17 13
7 Answers

Anyone got a detail for using 2" exterior rigid foam w/ stucco cladding?

Working w/ a builder on a 3 story, multi-family where we spec'd 2" exterior foam. The builder is using stucco cladding and to attach the stucco "chicken wire" they are using a metal z-clip that will go behind the foam, defeating the intent of the foam to elimate thermal brigding. Any help appreciated. thanks.

In Green building techniques | Asked By mike keesee | May 4 11
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