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20 Answers

Sealing PT sill plate to concrete slab ?

I am a homeowner in the midst of a 2000 sq ft addition. Houston TX, foundation is a concrete slab. Walls (from inside out) are drywall, stick 2*4 framing with open cell foam, OSB, tyvek, air gap, brick veneer.

The builder used pressure treated 2*4s for the sill plate but there is no (capillary) barrier between the concrete and the sill plate. 3.5" of open cell spray foam is going in the exterior walls today.

Asked By Mark McFarlane | May 20 17
12 Answers

Opinions on my exterior options

I have posted a few times regarding my situation and have been provided a lot of great information from GBA. I have not really been able to figure out what would be the best option for my situation. So i thought i would try and summarize and hope the minds here can point me in the right direction.

Current house climate zone 6
drywall
poly
2x6 16"oc fiberglass batt
plywood
Wood siding
2.64 ACH

The siding is being ripped off as it is failing in multiple places

Plan
Inspect sheathing/framing for water issues, replace as needed
Tape seams of plywood
Add Tyvek or similar wrb

Asked By Jeremy Archer | May 15 17
13 Answers

How to deal with duct-work that installed in unconditioned attic and a powered attic ventilator?

I am a homeowner of a brick ranch built in 60s in climate zone 7 and it is about 1,800 sqft.

The previous owner had the furnace and ductwork were installed in the attic and a powered attic ventilator (PAV) too in 2013. The attic floor does have some fiberglass as insulation material and it is about 8 inches. The ductwork is insulated flexible duct (supply duct is black from the outside and the return duct is silver from the outside).

Asked By TedLiu | May 22 17
2 Answers

Use foam board underneath fountain footer?

I am installing this fountain in PA:

http://campaniainternational.com/uploads/assembly/FT-240%20Three%20Tier%...

I don't want to dig 36 inches to the frostline.

Can I dig 2 feet, put tamped 3/4 clean stone, place XPS foamboard and then pour concrete?

Asked By John Sean | May 22 17
4 Answers

Passive solar design and HVAC sizing

I just used CoolCalc.com software (free to use online) to do a Manual J. analysis of my heating and cooling needs, since I just found out that I may need to replace my 13 year old HVAC system. One of my 2 heat pumps has a leak and needs to be recharged, and I am considering my options, so I wanted to get an accurate estimate of my heating and cooling needs. I found that the Manual J. heat loss calculations do not take into account the heat gain from the passive solar design, (except for cooling loads).

Asked By Ron Nachman | May 22 17
7 Answers

Can I combine floor and wall heating in a solar passive house to avoid overheating?

I have consulted many "experts" on highly insulated houses, most of them recommend to use ductless heat pumps to heat the house. But I am a radiant heat addict...
Apparently the problem with radiant floor and passive solar is that when the sun comes out, the southern side of the house is too hot because the concrete slab has heated during the night and is warm and when the sun comes out it can bring it to a much higher temperature.

Asked By Micheline Freyssonnet | May 22 17
6 Answers

Help with vapor barrier - On-grade engineered wood

Hello All. Thanks for a great site. I have been reading quite a few Q&A regarding this topic but seems to be still confused. So I appreciate any assistance.

The home is located in the Dallas area (zone 3a I guess) and was built in 2010 with a plastic vapor barrier under the slab. There's also gutters and grading all around.

I'm trying to install engineered wood [flooring] on the first floor (on grade) and based on the consensus here is to put another vapor barrier on top of the slab as a safety measure in the long run. This is where I get confused.

Asked By Ram777 | May 22 17
1 Answer

Average lighting, appliance and plug loads for PV sizing?

In doing some energy modelling for a future single-family net zero residence (in Canada), I am running into the problem of trying to guesstimate what the total lighting, appliance and plug loads will be. Because it can be different with every specific family, I'm wondering if anybody has any links or resources they can provide that offer average values for these loads that one can use. I will calculate the heating, cooling and hot water loads separately, but am hoping somebody has some suggestions for those remainders.

Asked By Burke Stoller | May 23 17
1 Answer

Attic insulation in SF Bay

Apologies in advance for what feels like a question that's probably asked too often, but I haven't been able to find the answer on your site.

Can anyone offer any suggestions for finding good contractors? I live in the San Francisco Bay Area, and of all places I would think I could find some experts in green construction out here. But Yelp and Consumer Checkbook don't strike me as the best of options because the consumers who do the ratings might not know the difference.

I want some insulation in my attic, or possibly a foam roof, or someone who can guide me one way or the other.

Asked By Robert Shelton | May 22 17
9 Answers

Insulating polyiso with EPS in a roof stack

Has anyone tried protecting the R-value of Polyiso by putting it inward of EPS?
We are contemplating insulating a roof deck with an over-deck foam stack.
We are in Zone 5A (Lake Effect, N.E. Ohio) and the idea is to maximize R-value by using "some" Polyiso. In an attempt to maximize the R-value with a 6" foam stack here's what we have come up with. From inward to outward:
1) Rafters
2) Zip System OSB Decking
3) 2" Polyiso (R-6.7)
4) 2" EPS II (R-4.2) - Staggered
5) 2" EPS II (R-4.2) - Staggered
6) Roofing Membrane
7) Furring and metal roofing
Total R-value of 30.

Asked By Dave-OH | May 19 17
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