Q&A: A Forum for Green Building Experts and Beginners

Q & A Instructions

[Click map to enlarge]

The GBAGreenBuildingAdvisor.com web site has a wealth of articles on a wide variety of construction topics. Before posting your question, you may want to check out the articles on this page: How To Do Everything. You just might discover an article there that provides the information you seek.

Please register for a free account or sign in to ask and answer green building questions.

If you want to post a question, the usual rules of courtesy apply:
1. Be nice.
2. If you can't be nice, be polite.
3. If you can't be nice or polite — well, please be brief.

To attach a photo or illustration: Under the box labeled “More explanation,” look for the words “File attachments.” Click that, and you should be able to attach a photo.

Thanks for joining the conversation!

1 Answer

Feasibility of exterior insulated stucco panels

In the process of trying to finalize the wall design that would allow 2.5" exterior rigid "outsulation" over CDX sheathing. Planning for final stucco/stone veneer exterior. The issues that have been discussed on the board are surfacing. Two that concern me the most :

In Energy efficiency and durability | Asked By Sal Lombardo | Aug 13 15
2 Answers

UPVC vs. fiberglass windows

Hello all. Building a new home in the Philadelphia area.

Looking for windows. Was considering fiberglass, but have been reading online that uPVC may be just as good but cheaper.

Can anyone comment on the pros and cons of each material?

Thank you.

In Green products and materials | Asked By Boris Rubinstein | Aug 12 15
3 Answers

Drywall ceiling

I nailed by 28 inches in the drywall ceiling because of weird joist distance.
The interval of nail is 28 inches and 20 inches..
it will be fine?

In Green building techniques | Asked By Mansig Yoon | Aug 10 15
1 Answer

Soffit vent is blocked. Weird. I don't know what to do.

We live near Chicago and recently bought a 55 year-old, ~1200 sq ft ranch house with a relatively low roof. We are trying to install more insulation in our attic (there is currently ~3" of blown-in insulation). In the process, we found all kinds of references that you should not block the soffit vents, need to maintain air flow, etc.

In General questions | Asked By Mansig Yoon | Aug 12 15
15 Answers

Approximate cost

I'm looking to install Geothermal heat/ac in a commercial building in north NJ. I need the approx cost for a 12,000 sq. ft. single-story office building. I was inform 6 units, 4 wells but no specifics were given. I know its not all the info needed but i was hoping to get a high ballpark figure.

Thanks, Rich

In Green building techniques | Asked By Richard Hussey | Aug 10 15
5 Answers

What material is best for furring strips behind Hardie Reveal panels?


Looking for the best material to use as 1x4 furring strips behind Hardi reveal panels? I have been told Douglas Fir is best cost and rot resistant, some say Western red cedar (sounds expensive), Pressure treated wood, or Trex (plastic wood alternative), or of course there is the metal varieties.

One issue is read with PT wood is that any contact with aluminum or other metals causes corrosion so you have to paint over that (more expense)

In Green building techniques | Asked By Tauran Ivall | Aug 12 15
1 Answer

Rigid foam and rafter tails

The attic is conditioned space due to foam spray on the underside of the roof deck. Foam also fills the void between top of wall and roof deck. So, when I install my exterior rigid foam should I stop at the top of the wall or cut out for rafter tails and continue the foam to the bottom of the roof deck.

In GBA Pro help | Asked By Robert Brown | Aug 12 15
3 Answers

Best way to seal rafter baffle

I am looking to use the accuvent baffles in my rafters from soffit to ridge vent. I assume I need to seal them properly for air leakage. Do I use tape? a paint? A foam in a can (great stuff) - god I hope not since I will need a ton of it. LIke 2700 linear feet!!! 54 rafter bays, each 25 ft long, both sides

In Energy efficiency and durability | Asked By Joe Watson | Aug 10 15
5 Answers

Pool solar panels: Will they naturally thermosiphon?

I have a 35,000 gallon pool with a south facing roof top right next to it. Solar panels would be a natural fit. BUT, the filter pump and mechanicals are on the opposite side of the pool. Before re-plastering when I first bought the house I installed 2 ea.1 1/2 ' PVC fittings on the house side of the pool and capped them off.
The question is, will I need a large, 1 HP pump to circulate water to the roof (15' head +-), will a small fractional HP recirculating pump work, or will the water naturally thermosiphon up and down?
I can see where any air leak up high would be a problem.

In Mechanicals | Asked By Richard Stutsman | Aug 11 15
7 Answers

Can I add insulation to a "cathedral" ceiling that is poorly insulated and has no eaves?

We recently bought an old 3 story 4 flat. One of the units is empty and we have 18 days to improve the insulation in the upstairs that was converted from an attic. The joists are irregularly spaced some 16 some 20 or 24 " apart. I think they are 2 X 6's but may be 2 X 4's. The current fiberglass insulation batts (probably R11)are thin and sometimes smaller than needed. For example a 15" wide batt in a 20" space. The rooms are hot in the summer. Can I blow in some fiberglass or possibly slide some properly sized width batts in the cavities for now without causing damage from moisture?

In Energy efficiency and durability | Asked By Dan Bailey | Aug 11 15
Register for a free account and join the conversation

Get a free account and join the conversation!
Become a GBA PRO!