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11 Answers

Is 3/4" closed-cell spray foam enough for flash & batt?

I'm building a house north of Pittsburgh, PA in climate zone 6. The house is built with 2x4 walls, 1" blue dow styrofoam sheathing (r-5), and brick outside that. The house is about 3300 sqft. The standard insulation would be r-13 fiberglass batts (which I guess would give the walls a total of r-18).

I already opted to upgrade to geothermal heating/cooling. I was told that I can also upgrade the insulation to a "flash and batt" system for about $3100. They said they'd use 3/4" of spray foam (which would be on top of the blue board sheathing).

In General questions | Asked By Greg Miller | Feb 4 12
4 Answers

Firestop exulation retrofit practical/compliant design

Short version: Do any fiber cement cladding manufacturers honor warranty or otherwise approve mounting on furring strips over exterior fiberglass or mineral wool? Or is there another practical/compliant exterior insulated wall design that resists fire on a tight setback, to the satisfaction of a permitting official?

In Green products and materials | Asked By Michael Gold | Feb 4 12
3 Answers

Historic tin roof

Hi, I recently bought an 1840s farmhouse with an original, as I am told, standing seam tin roof. It's a one and half storey, timber framed house with a layer of brick. I haven't figured out if the house is 'piece sur piece' styled log house or if it is post and beam that was later covered in brick. I don't know much about this, just started to learn since I bought the house. Anyway, the roof has wooden soffits with no vents, there are no real roof vents either.

In Energy efficiency and durability | Asked By Michael Jordan | Feb 4 12
12 Answers

A question about straw insulation...

My name is Michael Garrison, a 30 year carpenter with 17 years building experience in Alaska. I had a friend who used straw insulation. The condensation inside the structure caused a mold to develop that put off a gas that caused a serious lung infection and almost killed him. Have you heard of any other instances of this effect? Thank you for your time.

In Energy efficiency and durability | Asked By Michael Garrison | Feb 1 12
1 Answer

Anyone tried HomeSEED yet?

Just saw this yesterday. Looks like an interesting way to explore alternative strategies to meet energy goals.


In General questions | Asked By Larry Burks | Feb 3 12
12 Answers

Rigid Foam on the interior face?


I am working on plans for a new house and have been looking at a couple of options for the exterior wall assembly. Climate zone 5, coastal, very humid summers. Will probably be forced air heat and central AC for cooling.

Looking for approx. R-40 walls.

I am leaning towards a double 2x4 stud wall filled full with cellulose. I prefer the environmental benefits of cellulose over spray foam and rigid foam. It also seems like detailing/ flashing at windows/ doors etc are much easier with a double stud wall than rigid foam on the exterior.

In Energy efficiency and durability | Asked By Chris Harris | Feb 2 12
1 Answer

Exterior Rigid Insulation and Siding

I recently completed a single family home in Va with 6" stud walls (cellulose) and exterior rigid insulation. I wanted to have 2" minimum exterior rigid, but the contractor pointed out that the literature on the specified siding (Hardi-Plank) only supported up to 1" rigid insulation. They also did not seem to support a rainscreen detail of any type when rigid insulation was used.

In Green building techniques | Asked By Grayson Jordan | Feb 3 12
0 Answers

A nice TV news report on Alan Gibson's Passivhaus development

Here's a link to an interesting TV news report on Alan Gibson's Passivhaus development in Belfast, Maine:

Congratulations, Alan -- looks good.

In PassivHaus | Asked By Martin Holladay | Feb 3 12
5 Answers

Spotless HVAC filter

Why would my HVAC filter show absolutely no dirt or dust? It fits tightly and there is no residual dust in the air handler unit. A couple of years ago I found that the top of one of the return runs was never closed in, leaving it open to the mechanical room in which that return was located. I covered the opening with duct board and sealed it with mesh and mastic. The majority of returns are panned (what a joke!) and are not accessable. Those that are accessable, I have also sealed appropriately. The filter may not display dust, but the house sure does! Climate Zone 5.

In Mechanicals | Asked By Chris Brown | Feb 2 12
1 Answer

SIP nail board

Can any one tell me the guage of the metal skin on SIPs 4" nailboard?

In Green products and materials | Asked By Bruce Glanville | Feb 2 12
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