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6 Answers

What kind of exterior rigid insulation should I use?

I am working on a series of small 1950 vintage homes. I am planning on filling the walls with cellulose blown from the outside, adding exterior rigid insulation, and re-siding. The exterior finish is not yet known, but I would like to offer the Architect something that works regardless what is chosen (within reason).

I had been thinking about some kind of un-faced extruded foam (so that I do not add any vapor barriers to the system) but people keep giving me funny looks when I say this.

Any suggestions?

- Ron

In Energy efficiency and durability | Asked By Ron Flax | Mar 23 09
2 Answers

I'm concerned about rigid exterior insulation being a vapor barrier

Hello, sorry to add yet another question about exterior rigid insulation, but I can't find information on this elsewhere. I am working on designing a Habitat for Humanity home in a mixed-humid climate. Dow will give us insulation free, and I want to wrap the home in 1" over the sheathing and building felt, and under cement-board cladding. I am concerned about it being a vapor barrier, however. I can not find perm information for Dow Stryofoam. Any thoughts?

In Green building techniques | Asked By David Quillin | Mar 24 09
5 Answers

Using 1" XPS as the vent baffle

I am thinking of using 1" XPS as a vent baffle in a cathedral ceiling, similar to what is shown here: http://www.clip-vent.com/index.html

I wouldn't actual use that product, but the same idea. I am thinking of spacing the xps 1.5" off of the underside of the roof sheathing, and sealing any gaps with a combination of sprayfoam and tape. The roof would have soffit and ridge vents. The rest of the bay (approx 7") would be insulated with fiberglass bats. I am building in a cold climate, and the space is a conditioned room over an unconditioned garage. The roof is 2x10 stick framed.

In Energy efficiency and durability | Asked By Tobias Richon | Feb 27 09
2 Answers

Insulation achieves its maximum R-value by touching the air barrier on all it surfaces. How much R-value does attic insulation

loose by being open at the top?

In General questions | Asked By terry nordbye | Mar 15 09
10 Answers

any advice about insulating walls in an old house?

i'd like to not have to tear out the interior walls. foam products inserted from the top might expand too fast and not make it to the floor. someone suggested pouring in vermiculite between the studs. i'd really appreciate suggestions/advice. thanks, robin kautzarm@joimail.com

In Green building techniques | Asked By robin kautz | Feb 5 09
2 Answers

Make-up air for Kitchen Range Hoods

I have a builder that insists on installing a 1200 cfm range hood. What is recommended for make-up air (rate and preferred installation)

In Mechanicals | Asked By Sean Bleything | Mar 2 09
2 Answers

How much R- value do insulating shades/ blinds add to a window?

They are somewhat tight on the top and bottom but have around a half to quarter inch space up the sides. Installers and salesman will tell you they can make hair grow on an apple- should I believe them?

In Green products and materials | Asked By terry nordbye | Feb 28 09
2 Answers

Does it make sense to use ICFs for a frost protected shallow foundation?

I will be building a house near Amherst Ma. in an area with a high water table. FPSF seems like the way to go. ICFs are quick and easy. Is there any reason not to use them for this? Any opinions on insulation - xps or eps? Any recommendations on waterproof material under the slab? I have heard polyethylene gets brittle and breaks down over time.

In Energy efficiency and durability | Asked By Ralph Hill | Mar 11 09
2 Answers

Do I need house wrap under exterior wall rigid foam ?


Do I need to put house wrap ( Tyvek etc) between exterior 3/4 "iso rigid foam (taped)? Can I go naked or just 15 lb felt?

I'm looking at tech drawings on the site and it's not shown.

My guess is not, but why not ask before I go through all this an d do something dumb.


In Green building techniques | Asked By Steve Greenberg | Mar 10 09
3 Answers

High-performance insulation in cathedral ceiling

I'd love to hear feedback on the most efficient and cost-effective way to insulate a cathedral ceiling constructed with scissor trusses (residential construction). I'm considering having the trusses built with 16" or 20" heels and blowing in cellulose to achieve the insulation levels desired. Another option could be spray-foam (closed cell). I'd love any feedback, i.e., pros/cons to each or a better method.

In Green building techniques | Asked By Claire Anderson | Feb 3 09
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