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!

5 Answers

Vapor-permeable barriers and brick walls (MemBrain, Intello+, etc.)

I have a ~100 year old solid brick house in zone 5 - Northern IL ~1/2mi to Lake Michigan. The walls are 2+ courses wide with ~1" gap between.

We're slowly rehabbing the house floor by floor. And trying to decide what the best way to deal with air infiltration and vapor permeability. From my reading, it looks like I could put Membrain or Intello+ on the brick directly, then build a (non load bearing) studwall on the inside and insulate that.

Is there a problem with putting a variable perm barrier on a cold surface? .

In Green products and materials | Asked By Job Lenihan | Jun 22 14
16 Answers

Mechanical Ventilation in a Tight, Permeable House

Ok, I am going to thoroughly expose my lack of knowledge with this question (no claims to any expertise on my part), but I'm hoping that some of the experts here can comment on something I am thinking about.

In Mechanicals | Asked By Stephen Youngquist | Apr 16 14
7 Answers

Unsure about energy audit suggestions...

I apologize in advance for any length and confusion.

I'll describe the house:
Location is Mid-Hudson Valley NY.
2 story colonial (I moved in about 2004). I think it had been built for someone else in 2003. Appx.

In Energy efficiency and durability | Asked By Louis Aller | Jun 23 14
1 Answer

What is the best combination to renovate my 1950 modern home?

Our one story 2,000 sf modern home was built in the Boston area in 1950 with a thoughtful floor plan stretched east-west, with lots of glass facing south, and a small amount facing the other orientations. We plan to add a study, half bath, screened porch and bring the laundry up from the basement so that we can more easily "age in place" for twenty years. A few years ago we replaced the tar and gravel roof with a white TPO membrane on PIC roof sheathing. The original Hopes-type steel casement windows continue to grow mold despite quality storm windows and most of the cranks are broken.

In Energy efficiency and durability | Asked By Timothy Oldfield | Jun 24 14
20 Answers

Gunter Lang conference in Montreal/ NY June 2014

I was lucky enough to attend to a conference given by Gunter Lang ing. of Austria in Montreal ,
which was organized by a newly forming Passivhaus Quebec movement which should be called : Maison Passive Quebec in collaboration with Quebec section of Canada Green Building Council.

I was probably one of the least "professionals" attending the event,
as most seemed to be either architects, manufacturing reps or building techs.

I knew very little of mr Lang other than reading his name a few times in the last 2-3 years,

In PassivHaus | Asked By Jin Kazama | Jun 21 14
5 Answers

Double-Studs and Roxul

I am working with a builder to finalize design of a house on the great lakes in Canada (zone 6).
Our wall plan is 2 x 2x4 with 3 layers of roxul batts vertically in the stud bays and horizontally in between the stud bays and interior poly vapour barrier. The builder has a good reputation for energy efficient houses and reports no problems in walls he has investigated after many years in place.

From reading about monitoring moisture levels in double stud walls ( http://www.greenbuildingadvisor.com/blogs/dept/musings/monitoring-moistu...)

In Energy efficiency and durability | Asked By Jake VanDor | Jun 24 14
8 Answers

Stick-framed equivalent to high-heel/energy truss?

Does anyone have a framing detail that shows how to create a high heel area when using traditional stick framing? I want to get lots of insulation on top of the wall's top plate, but I don't want to order pre-fab trusses. There is a 50-50 chance that there will be a structural ridge beam (as opposed to non-structural ridge board) in the design, in case that makes a difference (which I think it should).

How do you give yourself a good say 20" of insulation space right to the edge of the exterior wall, when your framing members are 2x6's or 2x8's?

In Energy efficiency and durability | Asked By Zenon Tymosko | Aug 20 13
2 Answers

2x12 as a ceiling rim joist to replicate raised heel truss?

I'm adding onto my house, extending the living room off the front of my house. The existing structure has 2x4 attic/ceiling joists, I'm planning on extending 2x6 joists 2 feet back into the existing ceiling and sistering them to the existing joists. I'll leave a supporting beam under that joint when I take out the existing front wall, I believe I should be ok there. The big question I'm facing is how to do the rafters as I want to do a raised heel rafter.

In Green building techniques | Asked By Tony Rigdon | Jun 23 14
3 Answers

Ceiling service cavity

I'm sold on having a service cavity. In the walls, it's easy to see how to implement one with double stud walls but. However the ceiling is not so apparent. Is it easier to delay building interior partitions till after the trusses are in place and the air barrier material installed on their bottoms? Should the interior partitions be the same height as the exterior walls or only to the bottom of the cavity? Is there a "preferred method of attaching the "ceiling joists"?

In Energy efficiency and durability | Asked By Jerry Liebler | Jun 21 14
3 Answers

An unhappy “insulating paint” company

A manufacturer of "insulating paint" is bummed out about GBA articles reporting that reputable research labs have found that so-called "insulating paint" is useless when it comes to reducing residential energy bills.

In Energy efficiency and durability | Asked By Martin Holladay | Jun 23 14
Register for a free account and join the conversation

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