Insulating rafters

[western_mass]

I need to install insulation into my rafters. Normally, to provide an air pathway to the ridge vent, one might install a styrofoam proper vent, then the insulation. As my wife is chemically-sensistive, this is not an option. Any thoughts on what I could put in my rafters to provide air flow? Also, since I'm using cotton, any thoughts on how to keep it in place? It doesn't have a paper vapor barrier on it that I could staple to the rafters...

It's always something.  

[jraabe]

Once installed, such a vent would not have the option of out-gassing to the interior. This would all be on the exterior side of the air vapor barrier.

You will need to cool her enthusiasm for installing the baffles, of course.  

And, there are other ways to do the baffles. There is a plastic coated cardboard that can be stapled up to provide the vent cavity (it is used by installers who do blown-in insulation).

[tjm73]

Why coudln't you use some sheet metal and a sheet metal break to fabricate the vents by modeling them after the styrofoam version?  Might not be the cheapest way to do it, but may work just the same.

[western_mass]

I think using sheet metal would be somewhat cost prohibitive. Someone suggested using fir strips to create a channel. I'll probably end up going that route. But what would be a quick-and-easy solution to keeping the insulation in place? We won't be covering the rafters for quite some time.

[tjm73]

I think I saw in another thread that someoen was using 1"x1" strips with narrow cut playwood to make wood vents.  Like so....

[western_mass]

I'll probably do something similar, although I'll have to substitute something for plywood as it off-gasses for years and years.

[glenn-k]

I'll probably do something similar, although I'll have to substitute something for plywood as it off-gasses for years and years.

How about real wood instead of plywood- If you can find someone local with a small sawmill it is very easy to make lots of 1/4" thick or whatever you want with a bandsaw - others can do it but more waste.  Use 1/4 inch crown staples or brads to attach it quickly using air tools.

Daddymem has free trees - you could make all the boards you want.

[peg_688]

I think using sheet metal would be somewhat cost prohibitive. Someone suggested using fir strips to create a channel. I'll probably end up going that route. But what would be a quick-and-easy solution to keeping the insulation in place? We won't be covering the rafters for quite some time.

 A nylon twine , or juke if nylon HAS outgassing , stapled up to the undersided of the rafters will hold it up . Just run it back and forth stapling it to the rafter. Either with a hammer tacker or air driven staple gun .

 Or buy the wires made for the same process , they are a bit longer than the  rafter / joist bay you just shove them up and in , the wire bends and the points dig in .

 It should work with the cotton batts , just like with Fiberglass.

 Good luck , PEG

   

[hobbiest]

I was assuming that the cotton insulation is loose fill, blown in style of insulation.  If that is the case, you could staple burlap to the underside of the rafters, using cedar lath as a huge washer to keep the staples from pulling through.  Could work with batts too.  The thing that most concerns me with any option however, is the flamability of the cieling.  Another option would be woven grass, tatami mats, they are cool looking.  Or the bamboo roll up curtains.  For air space, I think 1/4" is all that is required.  If that is the case, you could again use lath, sold in lengths up to 16', with a panel of cardboard, single thickness wood paneling (if you can find any) or, bamboo roller shade.  The bamboo would be stiff enough (unlike burlap, to resist being pushed up by the insulation.  Put another lath in the middle of each bay.  If more than 1/4" is needed, layer it.  lathe is inexpensive.  Of course if you have a table saw, just rip down 2x4.

[Amanda_931]

My impression is that almost any substance known to humankind can have people sensitive to it.

Oak, for instance.

Fortunately, not everybody is sensitive to everything.

Paula Baker-Laporte has a book on how to specify houses to avoid a good many problems.  Information and and I think some of her articles are here:

http://www.bakerlaporte.com/

And there's something called the Healthy House Institute--soon to be closing--with more books and information on building for (or by) the sensitive.  Although they will not be reprinting their books.

http://www.hhinst.com/booksvideos.html