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4 Answers

Zone 1 home addition — Dual-zone HVAC strategy?

I'm building a 1,700 sq. foot single story addition to my home in Houston, TX. 1,000 sq foot are a woodworking shop, 700 sq feet are living space. Living space is multi-room, think small apartment (kitchen/den, bedroom, bathroom, closet). Shop is one big room with a separate mechanical room. My current HVAC system won't handle the 700 sq feet of living space, which is also on the opposite side of the shop (maybe 100' from the current hot-attic system).

Current house is traditional stick frame, brick veneer with batt insulation and blown-in in attic. Gas available for heat.

Asked By Mark McFarlane | Jun 27 16
40 Answers

Best exterior wall design within standard 2x8 dimensions

I have been reading several of the GBA posts and articles and I don’t seem to locate the answer to my question so I wanted to drop you a line by email.

I am located in Saskatchewan, Canada and currently have a house under construction that is well under way. That being said I won’t over complicate it with detail but the house is not a high efficiency design and I am not and don't pretend to be knowledgeable on a lot of points that are covered on GBA.

Hhowever, this is what i have

Construction detail:

Southeast corner of Saskatchewan, Canada 15 miles north of North Dakota

Asked By chad online:) | Feb 21 16
3 Answers

Insulating the underside of a concrete deck?

I have a 2-story garage project where the lower level is built with ICF walls...R-25....and PEX radiant heated floors with an R-10 underslab insulation but the ceiling consists of the metal concrete pans and +/- 8" of concrete and rebar. Assume that space above is unheated.....it might also get insulated and heated from time to time when the homeowner needs to do automotive work.....but in general it will be unheated.

Asked By JONATHAN SCHOLL | Jun 27 16
3 Answers

Closed-cell foam versus thermal bridging

I have read several of Martin's articles and reader responses regarding the benefits of using closed cell spray foam on the underside of unvented roof decks. Because it is vapor impermeable, you can spray the underside of the roof without fear of vapor migration to the cold sheathing...so long as it is the proper R-value..... which would then cause rot over time. That's all good. In a cathedral ceiling or gable end wall, what happens to the rafters or studs which cannot be encased in the foam due to the need for drywall?

Asked By Jonathan Scholl | Jun 27 16
5 Answers

Two layers of insulation or one?

We are installing 2" of Hi-load XPS rigid foam insulation under a heated slab in zone 4a and we have the option of doing 1 layer of 2" insulation or 2 layers of 1" insulation. I'm wondering if there is an advantage to overlapping the seams or if it's inconsequential at the end of the day. We will be taping the seams.

thanks,

bigern

Asked By Big Ern | Jun 27 16
15 Answers

Geothermal vs. air-source heat pump

I have researching and getting quotes on hvac for a while now.. It is getting to crunch time.
Well insulated, tight house.

All three quotes include:
3 units, 3 air handlers, each zoned 3 times. Rigid Trunks and short flex runs.

option A. Carrier 18seer 25vna08... 5 stage. ( I don't like the potential harmonics problems of their greenspeed)

option B. Lennox x25 top of their line variable.

option c. Waterfurnace 7 series geothermal units. horizontally drilled ground loop.

Asked By Dean Sandbo | Jun 22 16
7 Answers

Is a dehumidifier needed in a tight house?

I've read several times that it's common for tight, well-insulated homes to need supplemental dehumidification, as the AC doesn't run enough to dehumidify the home.
As a person who is especially sensitive to humidity, I'm very interested in this.
I wonder if an equal level of comfort can be achieved more economically with a higher temp. set point but lower humidity. (In my case, Chicago area- warm and humid in the summer).

Asked By Ben Rush | Jun 27 16
1 Answer

Does this vapor barrier underlayment offgas?

Hi!

Thanks in advance for any help! Putting cork floor in a basement and need a vapor barrier. Of these three choices, does it matter which one I use from an off-gassing standpoint? I am trying to understand if these products off gas toxic chemicals into the home. The cork flooring is pre-treated so we won't be sealing it once it is down.

This one is "Bonded polyethylene" but I don't know if that off gases.....?
http://www.wayfair.com/Shaw-Floors-2-In-1-Foam-Underlayment-100-Square-F...

These two seem less likely to off gas based on description but I don't know:

Asked By Melinda S | Jun 27 16
30 Answers

Direct vent vs. power vent gas water heaters

A recent blower door test/audit has alerted me to the fact that my natural draft hot water heater can backdraft in worse case scenarios (range hood/clothes dryer/bath fan on). It seems to reverse back to a correct draft after a few minutes. It's only about 6 yrs old, so I hate to replace it, but not as much as I hate the idea of the back draft.

Asked By Erik Addy | Mar 8 16
8 Answers

Making the best of a misplaced vapor barrier

The project: an aluminum-bodied step van to be converted to a low-energy tinyhouse. It will move around once in a while, and needs to handle a range of climates.

The materials:
- heavy aluminum skin, built fairly air-tight (much tighter than corrugated RV siding)
- 4" thick fiber/paper-faced polyiso
- plywood interior panels, most likely
- a 100W heater/vapor generator that runs on potatoes and wine
- additionally heated by a woodstove when it's feasible, catalytic propane when it's not. I'm also looking into air-air heat exchangers.

Asked By Geva edhrven | Jun 13 16
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