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

[Click map to enlarge]

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

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!

2 Answers

We've had 5 estimates for a high efficiency furnace to replace our 30 yr old beast. Two guys said no problem. Then the final 3 raised questions about the condensate. We do not have a sump pump or utility tub in the basement for drainage. One guy said we couldn't vent outside because it would freeze ( we live in SE Pennsylvania), so we'd have to put a trap on one of the plumbing lines and divert it there. Second guy said no to the trap because it's against code and yes to going outside because only a short piece of the pipe would be exposed outside and freezing wouldn't be a problem.

In General questions | Asked By Tammy Crabtree | Oct 19 11
5 Answers

Does anyone have any insulation and/or air sealing details for a shared masonry wall separating two homes. The masonry extends into the attic and was identified as being very leaky in a recent blower door test.

In Energy efficiency and durability | Asked By Aaron Dent | Oct 19 11
3 Answers

I am in the process of designing a home in Maine. Its roughly 1500 sq ft ranch style home with a slab on grade, double stud wall with 11.25 inches of dense pack cellulose and 18inches of loose fill in a vented attic. I have been contemplating the heating system and have been thinking about radiant but it seems like that may be overkill, and somewhat expensive. I was planning on a diamond polished concrete floor for the interior, so I was wondering with 4inches of rigid foam under the slab will the concrete be cold most of the time if using say a minisplit unit or even a woodstove?

In Green building techniques | Asked By Mark Hinkley | Oct 19 11
8 Answers

We have a historic house that is undergoing a deep energy retrofit with rigid insulation being applied to the outside and then strapping and new siding. The contractor has ripped off a few layers of asphalt siding and is now down to the original siding. He would like to keep it on and simply put the new rigid insulation over the siding. It seems this will create some nice air pockets which be good insulators, and be a cavity for drying if needed. Does anyone have experience doing this and any input on pros and cons versus taking that original siding off and going down to sheathing?

In Green building techniques | Asked By Phil Kaplan | Oct 19 11
19 Answers

We are building a new house and had planned to use triple-pane glass in extruded fiberglass/composite frames. In particular we have one large picture window 96"W x 72"H. Just found out from window provider that they cannot (will not?) do this window as triple-pane due to size....particularly the weight of the glass. He suggested alternative of double-pane using new Cardinal i81 coating which he (and Cardinal website) claims achieves nearly the same thermal efficiency as triple-pane (thermal efficiency was major reason for using triple-panes).

In Energy efficiency and durability | Asked By Dave W | Oct 16 11
6 Answers

Just to give you a mental visual, the house is 1460 sq.ft. single story truss roof and vented crawlspace. Front half of roof has two dormers.

Could you elaborate on air sealing the attached garage.
Seal gaps only or seal gaps and insulate attic floor over garage?
Would vapor barrier be beneficial since rest of attic has none?

Garage roof has front dormer with no eave vents.
The rest of attic is insulated and vented (bird block eave and ridge vent).
How would this affect the balance of intake & exhaust for entire attic pertaining to moisture control?

In Energy efficiency and durability | Asked By James Cavallaro | Oct 17 11
4 Answers

So we haven't hired the builder of our future house yet, and are trying to figure out how to ensure that air sealing is a priority for the builder as well as for us. Certainly, we will specify what we can, and will choose someone with a good reputation and an apparent commitment to quality work. Still, the best plans depend on execution, and not everyone thinks of 4 ACH 50 as a bad score. It seems that 2 ACH 50 should be a good result and reasonably achievable, but how do I get a builder to really try to achieve it?

In Green building techniques | Asked By Ian Brown | Oct 19 11
2 Answers

Hi All,
All the local builders I have asked use highly toxic glue to hold the window sills down. Does anyone recommend a green, more sustainable material?
Gratefully,
William in Vermont

In Green products and materials | Asked By Styles Brook | Oct 19 11
5 Answers

In lieu of Martin's suggestion; can a propane gas furnace in an attached garage be brought into the house thermal envelope by just framing in around it with insulated walls and access door?
Furnace and hot water tank are vented together.
Preexisting bedroom is on other side of garage wall.
What code violations to avoid?

In Energy efficiency and durability | Asked By James Cavallaro | Oct 17 11
7 Answers

My wife and I will be building our house next year. I’m in the research and planning stage and first order of business is to determine our insulation strategy. We’ll be building in eastern Ontario (near Ottawa) which sees average winter temps of around -13C (7F). I’ve recently come across the dew point calculation method posted last year by Martin. I was thinking of going the route of 2” XPS foam board with rock-wool cavity insulation on a 2X6 wall. Here are the calculations (assuming 70F and 35% humidity, therefore giving us a dew point near 40F):

Temp delta = 70F - 7F = 63F

In Energy efficiency and durability | Asked By Mike Goulet | Oct 14 11
Register for a free account and join the conversation


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