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3 Answers

What is the recommended or code requirement for finishing the bottom edge of exterior rigid insulation?

On the exterior of my home I plan on using 1/2" OSB, 1" rigid insulation, with 1x4 furring strips (and insect screen) creating a drainage plain, covered by fiber cement siding. I wonder if the fire code deals with this specifically or not? (Leaving the bottom edge and the drainage plain open to the bottom side.)

You have really the best articles dealing with exterior insulation and drainage plains, but I don't recall seeing if leaving the bottom edge exposed is OK or if it is better to put a drip rail under it, or what some other solution might be?



In Building Code Questions | Asked By Ron Lay | Jan 14 14
7 Answers

Is it cost-effective to get a lifetime hot water tank?

I have a gas hot water tank now, and understand that lifetime tanks are electric, which means I'd have to convert from gas to electric. I'm wondering if it's a wise choice, since electricity is
so much more expensive than gas. My current hot water heater is about 11 years old.

In Energy efficiency and durability | Asked By Lynne Pifer | Jan 11 14
5 Answers

Double stud walls and drywall nail pops?

Does anyone have any experience with double stud walls and excessive nail pops? I am building a double stud wall, and my carpenter is concerned that we'll have a lot of nail pops on the exterior walls because the secondary stud wall isn't braced on its back side by another layer of drywall or sheathing. Do double stud walls "require" the use of drywall screws? One option might be to put a piece of blocking at mid-span on the interior stud (at 5' on 10' walls in this case). That would trade off some thermal bridging for increased rigidity.

In Green building techniques | Asked By Jonathan Rich | Jan 14 14
8 Answers

Dimishished R-value of polyiso in extreme cold

Should I be using XPS as my top layer in a 6" stack installed on top of sheathing in zone 6? Also, is taping the sheathing when installing exterior polyiso redundant? Thanks

In Energy efficiency and durability | Asked By Robert Mason | Jan 13 14
11 Answers

Hot water runs out when I take a shower, and registers blow cold air

Hydronic air handler connected to a tank hot water heater.

I have a hydronic forced air heating system (just recently installed), is it normal for my hot water to not last now when I take a shower, and is it normal for the air coming from my registers to be blowing cold air when I am taking a shower?

Thank you!

In General questions | Asked By Dana Whitlock | Jan 11 14
6 Answers

Unvented vaulted roof/ceiling

I’m retired and disabled and therefore have a tight budget to build an addition onto my
house, a small apartment to accommodate a caregiver for myself. Some friends are
building it for me and I hired a local guy. We built a stone and cement
foundation with forms and used 3x8 fir for joists, insulated in between using
chicken wire to hold up fiberglass bats and vapor barrier.

The floor is flush 2x6 t&g fir and I had some 8x8 larch timbers I’ve had for 15 years which
were cut from ancient fire killed snags. These are the uprights at 3 and 6 foot
centers (6 foot for windows).

In General questions | Asked By Tim Wilson | Jan 13 14
7 Answers

Insulating a garage ceiling

I am designing a conditioned space over a garage in Chicago (Climate zone 5). The floor/garage ceiling structure will be 18" deep wood floor trusses, with 3/4" plywood floor sheathing and 5/8" gyp on the underside of the garage ceiling.

In Energy efficiency and durability | Asked By David Wytmar | Jan 10 14
7 Answers

Finding a financial institution for passive house construction

Hi. I'm in the process of trying to find a financial institution for a construction loan to build our passive solar home. My assumption is that I will come up short in trying to convince them that the initial cost of the structure will be more than a typical build (especially here in northern Maine where building techniques have not changed in decades) and the reasons for such an increase.

In General questions | Asked By Matthew Michaud | Jan 11 14
12 Answers

Foam sheets on underside of this ceiling to stop ice dams?

One room on the east side of the building has a cathedral ceiling with NO insulation. The ceiling is made from 2x6 T&G spanning 8 Ft on center, with the ends supported by walls and the center by a truss. The other rooms have an attic.

We would like to add insulation to the underside of the cathedral ceiling and are considering:
a) Two layers of 2”polyiso
b) Two layers of ¾ polyiso
c) 1x6 carsiding

(1) Do I nail the first layer to the ceiling or then to each other to hold in place?
(2) Should I use canned foam (what type) to seal the edges?

In Energy efficiency and durability | Asked By walt ott | Jan 8 14
1 Answer

Cause of water within an unconditioned space?

I have a situation in an existing building where water is building up on the underside of an exterior steel pan/concrete tread stair. The space below is an enclosed, unconditioned storage room. I'm assuming the water is from condensation due to the temperature differential between the exterior and interior surfaces.

I'm thinking of insulating the underside of the stair but want to confirm this is the best solution. Or, are there other ideas, such as vapor retardant paint which could work as well.

In General questions | Asked By Bruce Scott | Jan 13 14
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