I'm trying to figure out a way to hang 1" foam between rafters for a cathedral ceiling. The plan is to add some 1" scraps to the foam to make an airspace, hang the foam between the joist and then put regular fiberglass insulation stapled normally.
The reason I'm going thru this is that I have a lot of free insulation of the right width, but of less thickness than I need, so I'm bulking it up with the foam.
I'm going to be doing this in subfreezing temps, so I don't think glue would do, and nails or screws might go thru the roof sheathing the wrong way.
Has anyone used those pre-cut wires, would they hold up the foam (23" by 4' or 8') ?
Thought someone would have a good idea.
You might be better off using ripped pieces of 1x or 2x for the side spacers. Pop these into each rafter and this then gives you something solid to nail the foam to.
After you put John's strips on the side you could shoot the edges of the foam with a 1" or 1/2" wide crown x 1" to 2" long air driven staple to get it up quick - shoot it at a angle toward the edge into the spacer strip and joist. That would of course be if a compressor and air stapler is available. Many times air tool cost is justified by the amount of labor it saves. Then you can work during those gained hours at a paying job to pay for it and still have the air tool and save more in the long run. :-/ :)
Low tech-
How about 8d finsh nails every 4 ft as a stop for the first course and to hold for the later courses.
Its just foam right?
Would it be worth it to put those funny foam spacers up? (the very inexpensive jobs that tack onto the under side of the roof sheathing to provide space--they work for either 16" on center or 24")
Might still end up having to put in something on the order of what John and Glenn or Ryan mentioned to hold up the foam.
Hmmm, I'm liking Ryans idea. Put a couple long finishing nails in the rafters and then kind of "musch" the foam onto them.
I guess that's why Ryan gets the big bucks. [smiley=2vrolijk_08.gif]