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32 Answers

Vapor barrier or vapor retarder paint on open-cell spray foam?

I have seen some tout using the vapor barrier paint directly on open-cell foam before covering with Sheetrock, but as of late a general air of negativity towards that approach. I intended to use MemBrain under my drywall, but the open cell installer claims the paint works just as good for half the cost. What are thoughts on this? The stack up is a 2x6 wall with 2x2 interior Mooney strapping for a 7" thick OC foam fill wall over Zip board, taped of course. Then followed by a fired out ventilated assembly with Hardi siding.

In Green building techniques | Asked By Joe Suhrada | Oct 29 15
1 Answer

Blown-in insulation on open vaulted ceiling

I am had built with the plan to blow in insulation, and now that Im about to do it my mind is struggling with some physics.

I ceiling joist to the roof rafters with the help of an engineer to vault my upstairs bedrooms. This leaves me with a void of half the difference shown in the diagram attached. My question is will 5/8 drywall secured at 16" on center handle the load of blown in cellulose? If the insulation blows in as shown by the shaded area there shouldn't be any more than 18-20" over an given area. My biggest concern of course is how this would settle over time.

In Green building techniques | Asked By Marcus | Nov 17 15
8 Answers

Is this a good insulation strategy for apartment over garage (new construction)?

In early planning stages for a detached single-car garage/small shop with ~600 SF apartment above, as accessory dwelling unit (rental) to my house. Would like to approach Passive House standards for air sealing and overall energy use.

Footprint ~ 14' x 42', on a relatively narrow, deep lot. Thickened slab foundation. Stair to second story apartment inside building envelope. Climate zone 5, 6700 heating degree days, 10F winter design temperature.

Considering Remote wall system, as follows (from inside out):

In Plans Review | Asked By David Drake | Nov 15 15
2 Answers

Insulating over concrete garage floor

Our home is older - built in 1923, and has a great garage space, with a concrete floor that slopes outward. Several years ago, I repurposed the garage into a home gym, adding rolled covering that is 2.5mm thick. However, I still didn't like the slope of the floor as it limited the way I can arrange equipment. So, a couple of years ago I built a raised floor using high grade cedar decking - 6" x 1" on 12" centered floor joists. The floor is beautiful, stable, and works perfectly. Now I would like to insulate the space between the rubber matting and the raised floor.

In General questions | Asked By Paula Mueller | Nov 17 15
7 Answers

How to make a new room airtight?

I am building a room 14'L x 8' h x 42" wide inside my warehouse and the temp is constant 70 degrees..
Am using one interior wall as the back wall of my room. So I am building three walls using 2x4 studs
And I have already solved the problem of air sealing the door. I am not going to insulate or put on interior sheet rock. Just sheet rock on the outside. What should I do to make the room air tight.? I thought about wrapping the whole room in plastic and glueing it down on each stud or joist it touches.

In General questions | Asked By John West | Nov 15 15
6 Answers

Siga Wigluv vs 3M 8067 Flashing Tape

I'd like to tape the joint between the wood window bucks and the EPS insulation in my ICF wall, and want to decide on a tape.

I of course have read Martin's tape tests and it seems like Siga's Wigluv tape comes out on top for most tests, but 3M's 8067 Flashing Tape also rates very highly.

Of course some may say, just buy the best, but I'm trying to determine how different they are as Wigluv is about 2x as expensive as 3M 8067, and how much better is it really?

In General questions | Asked By Nick Hall | Nov 16 15
4 Answers

Stucco over exterior rigid foam - yea or nay?

I already posted this question under the title "accidental deep energy retrofit" but am hoping a stray stucco professional or engineer might weigh in with a more specific question in the title.

Proposed wall assembly: 2x4 framing (furred to 2x6 on the inside with polyiso foam and 1x, because we didn't know this siding project was in our future), plywood sheathing, 1.5" polyiso foam boards (taped) with the windows furred out on 2x2s, tar paper, lathe nailed to studs through foam with spacers, stucco.

In Green building techniques | Asked By Reanna Alder | Nov 17 15
3 Answers

Positioning a house (regarding window view wall)

We are looking to build in the Ashville, NC area, 2,100 - 2,200 feet above sea level. Mild winters. The view of this lot is to the south.

Does passive solar make sense in the southern US? Can we have our high window wall face south? We will be looking into the winter sun. We can build the roof overhangs longer from the house to assist.

Looking for opinions, articles or publications that address this. Gets confusing googling everything. Also natural gas is available; could go geothermal but very expensive. What is the next best way to go? Heat pump combined with gas heat?

In Interior design | Asked By Patrick Finnigan | Oct 24 13
7 Answers

Linear lighting options

I expect by the end of this decade I'll be buying nothing but LED's, but for now I'm still buying CFL's instead of LED bulbs for 3 reasons: Some LED bulbs are no more efficient than CFL's; some LED's have a rated lifetime shorter than CFL's; and LED's generally cost more than CFL's to buy.

Can the same be said for 4' linear utility fixtures? What's the best value on the market these days?

In General questions | Asked By Charles CAMPBELL | Nov 14 15
5 Answers

Proper ventilation

I'm considering building a sips panel home . what is the proper way to allow for , humidity removal , fresh air exchange , and compensating for exhausted air from , range hood at 300 cfm , clothes dryer at 250 cfm , and bath fan at 70 cfm ????

In Energy efficiency and durability | Asked By Scott Lawyer | Nov 13 15
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