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19 Answers

Unvented slanted roof with radiant cooling and NO polyurethane in 4C

We are in Everett WA, north of Seattle, right on the coast, zone 4C. I hope that our location will save us...
We have a low sloping steel, west facing roof. Double, 30 weight felt paper underneath to dampen rain noise. I presume 1/2" plywood sheathing. 2x12" rafters, 11" true depth.
We will install WarmBoard R (13/16" thick OSB with aluminum tracks) underneath the rafters for summer cooling and supplemental heating in winter.

In GBA Pro help | Asked By Jan Verschuren | Mar 11 15
9 Answers

DVHP on Southern Maine Coast

We are building a new home: 2,200 s.f., three floors living, southern exposure, closed-cell foam, R-40 and R-60 +-, radiant heat (I know, my wife insists), HRV, little propane stove.

We are seriously considering an AirGenerate ATI66 for hot water.

Here's my thinking:
Summer, run a supply duct from second floor, exhaust to first floor living area;
Winter, supply and exhaust from outside;
Shoulders, supply and exhaust from outside.

In Mechanicals | Asked By Peter Whitman | Mar 18 15
4 Answers

Duxton Windows

Has anybody used Duxton windows. We are interested in a very energy efficient window for a new home we are preparing to build. We are leaning toward Intus but I think I should consider a quality North American product. The windows we are considering are casements with simulated divided lights. I would prefer no maintenance on the exterior and thinking we could go with painted wood on the interior. Any thoughts/ideas/opinions would be appreciated.

In Energy efficiency and durability | Asked By william dempsey | Mar 19 15
1 Answer

Attaching plastic attic baffles together

I purchased a bunch of ADO ProVent 14 inch plastic attic baffles.

I'm retro fitting them in between the insulation and roof in a cathedral type setup in a bungalow. So, I need to attach 2 or even 3 together before sliding them in.

I'm thinking of using Tyvek Housewrap 2inch tape, either on one side or both of the attic baffles to attach them to each other before sliding them in place.

I'm open to other products to attach them to each other. Any advice?

In Green building techniques | Asked By Jeremy M | Mar 19 15
2 Answers

Is fiberboard air impermeable?

A recent GBA post noted that some builders are finding that OSB isn't always air impermeable. I'd like to know if fiberboard, such as Biltrite or BraceRite, is air impermeable. Specifically, I'm interested in trying to use it as an air barrier, in an assembly where I need the sheathing to be able to dry, and fiberboard has a permeability of around 20. But can it be an air barrier, if I tape or otherwise seal the seams? I can't find this info on the company's website or anywhere else I've been looking.

In GBA Pro help | Asked By Rachel Wagner | Mar 19 15
1 Answer

What is the layering sequence when installing a slab on grade?

Moisture barrier, rigid insulation?

In Energy efficiency and durability | Asked By Robert Marrapodi | Mar 18 15
3 Answers

Ground loop in bottom of new footings

Hi folks,

I like to experiment and try new things, so I'd be grateful for any constructive thoughts on the below. I'm respectfully asking for helpful views which may improve the system and help make it a success. I'm not going to pay for an engineer to design me a system. This is a DIY job to take the edge off in the winter, no more, no less. I'm digging trenches anyway, I just need to know if this stands a chance of working.

In Energy efficiency and durability | Asked By Nick Smith | Mar 18 15
6 Answers

Need help with insulating a block house with crawl space

I am remodeling an old family house that was built in the 50's, that is structurally in great shape, and is in middle Georgia (climate zone 3). The house has block exterior walls that extend down 18 inches into the ground to the footer. The crawl space is slightly below grade, but seems to stay fairly dry because the house is sitting on a small hill. I am doing a complete remodel, but not sure how to insulate without causing myself problems down the road.

In General questions | Asked By Robert Fordham | Mar 18 15
2 Answers

Above-grade wall insulation concerns


In Energy efficiency and durability | Asked By Kevin Steltenpohl | Mar 13 15
5 Answers

Convective looping in fiberglass batts?

A big knock against fiberglass batts is that even when a building exterior is well sealed and the batts are installed correctly there can still be additional heat loss due to convection within the building cavity. I usually hear this called 'convective looping'. I have heard this a few times as a justification for using spray foam, cellulose or BIBS. Does anyone know of any impartial research done into this phenomenon? Is it actually a significant form of heat loss in wall assemblies with fiberglass batts?

In Energy efficiency and durability | Asked By Nick Sisler | Mar 13 15
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