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!


11 Answers

Wall insulation and air infiltration

Hello,

I am doing some remodeling and I want to improve my energy efficiency at the same time. I will be replacing some windows in my 1950s house in Austin, TX, and I would like to improve the wall insulation and reduce the air infiltration as well.

In Energy efficiency and durability | Asked By Tom P | Jun 30 10
18 Answers

'Til We Meet Again...

To all the earnest participants in this Q&A forum:

My last comment about ADJAC on the "Heat-pump water heater vs. instantaneous water heater" thread was admittedly over the top (as follows):

"Can someone put a leash on ADJAC? He's single-handedly lowered the level of discourse on this site to the sandbox. He suffers from chronic verbal diarrhea, and - like a rabid - dog should be either muzzled or shot."

In General questions | Asked By Robert Riversong | Jul 6 10
19 Answers

Modifying Brick ledge for 2" of foam.

We are building a house with 2x6 walls with 2" of rigid foam over OSB. The house will be all brick. There is only enough room between the brick ledge and the wall for 1" OF foam. What are my options? Simply make the bridge ledge wider,, move the 2x6 walls in an inch. Increase the thickness of the basement wall from 10" to 12" . I am concerned that I will not have enough space to accommodate the floor joist. Thanks, Phil

In General questions | Asked By Philip Thompson | Jul 6 10
6 Answers

Trying to achieve Energy Star in an existing home

We are putting a small addition on the rear of a home and adding a second floor. We are reusing the entire floor system and subfloor which is diagonal 1x6. We are reusing about 75% of the exterior walls which are 2x4 with blackboard (or gyp board as it is called around here) and an existing brick veneer. The second floor and addition are obviously all new walls and floors - all roof is new. We are trying to seal the house up to achieve Energy Star. We are concerned that we may not be able to achieve this with all of the gaps in the existing floor.

In General questions | Asked By Danny Kelly | Jul 6 10
4 Answers

T-111 code question

Can I use studs, Tyvex, 5/8" T-111 siding -- instead of stud wall, 7/16" OSB, Tyvex, 3/8" RS fir siding?
Basically, I'm trying to eliminate the 7/16" OSB.

In Building Code Questions | Asked By Gary | Jul 6 10
14 Answers

Tight Homes/Good Ventilation

I am huge advocate of building tight homes. Air leaks, to me, represent poor workmanship that wastes a huge amount of energy. But, just for a minute, I want to be the devil's advocate, primarily because I hear this argument all the time. Tight homes need good, dependable ventilation systems or the occupants will suffer and the durability of the building will suffer......whole house ventilation systems, exhaust fans in bathrooms, hoods, sealed combustion gas appliances, etc.

In Energy efficiency and durability | Asked By Ed Welch | Mar 9 10
14 Answers

Does this wall assembly make sense?

I need some expert advice. Here is what I am considering for exterior walls:

siding (wood lap, LP, or fiber cement)
WRB (DeltaDry?)
Furring strips (oc to match studs)
4"-8" XPS or Polyiso foam
2x4 or 2x6 studs (16" or 24" oc)
1"-2" closed-cell spray foam in cavities
Drywall

Does this make sense for a cold/mixed climate (Omaha NE)? Is fiber cement to heavy for the furring strips? Is it worth fighting the battle with my local builder's on going 24" oc vs 16" oc? With the exterior foam, do 2x6 studs make sense or are 2x4 studs a better choice because of less material?

In Green building techniques | Asked By Michael Schonlau | Jul 5 10
42 Answers

Can you satisfy ASHRAE 62.2 with a recirculating kitchen range fan?

As a Green Rater for the LEED Homes program, I am involved in a fair number of new construction projects that are attempting Passivhaus level building tightness (< 0.6 ACH50). Of course, ventilation systems are a critical piece of all of these homes. All are using HRV/ERV systems to meet the Whole Building Ventilation requirements in 62.2 - Section 4.

In Building Code Questions | Asked By David Milliken | May 7 10
3 Answers

How to waterproof and insulate old foundation walls from the outside?

Is 2" XPS over dimpled membrane over blue skin a good idea? Should the foam go up all the way from footing to the rim joist which is 3' to 4' above grade? Or is it better to stop the foam at grade level? If going up is better choice, how to protect and finish the above grade portion of the foam? The foundation is 8" concrete block which is flush with brick veneer of exterior walls. Location - Ontario, Canada. Your input will be very much appreciated.

In GBA Pro help | Asked By Andrei Sosnovsky | Jul 5 10
5 Answers

Seam tape for plywood air barrier?

I am using plywood as part of my air barrier on a new construction project. I understand that the seams should be primed and taped to make this assembly relatively airtight, but I don't know which products to use. Any suggestions? The closest thing I am aware of that might work and is available at my lumberyard is Vycor—is this a good option?

Thanks in advance.

In Energy efficiency and durability | Asked By Tristan Roberts | Jul 6 10
Register for a free account and join the conversation


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