Insulation question

[xtremek]

Hey guys and gals, I got a quick question for you. I was given a bunch of insulation. The problem is that the insulation is for 16" centers and I need to put this in the ceiling and the trusses are on 24" centers. So any suggestions for how to cut in length wise and then how to splice it together? I've just about got the wiring done, so I want to finish this next. Thanks in advance for any suggestions.

 

[Richard Cranium]

use a sharp box knife, and a long 1x4 or some thing straight, and then just lay them next to each other snuggly.

 

[p_mori7]

The individual batts you have probably measure 16" x 48". I would cut them in half to make 16" x 24" and put them crosswise in between the trusses.

 

[67carl]

I had the same issue so I ran some heavy string across the joist and stapled them, then inserted a full width bat and another cut to fill the gap. Ain't pretty but when it's covered with drywall who cares?

 

[xtremek]

Is there any way to cut this faster than with a box knife? The batts are 15 1/5"x 94". Like you 67Carl, I'm not worried about the looks, just trying to find a better way to do this. The 30'x40' ceiling is only about 1/3 done and I'd like to get on with the show. I was thinking about duct taping the seams, but how would I get it to stick since the batts are so easily compressible?

 

[MScott]

Do these bats have paper vapour barrier? If so, you might be able to tape them with the tape used on exterior housewrap (Tuck tape) as it is very sticky. If not, you would not want to tape them together but rather use a plastic vapour barrier.
At to cutting, I would use a sharp kitchen knife rather than a box knife. Place the bat on a wooden sheet of plywood or OSB, put a straight-edge on the cutting line and cut with the knife. You will find this goes very quickly and you have a straight, even cut. Just cut the pieces a little wider than required so you get a tight fit between the trusses. You should have to compress the bats a bit to fit them. If you have trouble getting them to stay up, I would use 67Carl's idea of the string.

 

[beakie]

pile them X high
grab the wifes bread knife
cut just like a saw

put bread knife in tool drawer
go buy wife new bread knife

 

[joe6749]

Get some 24 wide insulation to use between the trusses then use the 16 wide stuff turned 90deg on top of the trusses

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[Jmatlock88]

Reiterating MScott’s advise, the way I cut insulation consistently is throw a piece of OSB on the floor, buy a 6ft long 1/4" by 2" steel bar (the weight helps), lay the bar over the insulation at the cut line, compress tightly with my knee and trim along the bar with a retracting utility knife (not a box knife..blade is a little short).

 

[info2x]

Get some 24 wide insulation to use between the trusses then use the 16 wide stuff turned 90deg on top of the trusses

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This is what I was thinking.

 

[xtremek]

pile them X high
grab the wifes bread knife
cut just like a saw

put bread knife in tool drawer
go buy wife new bread knife

lol.
Thanks everyone for the suggestions. The insulation does have the vapor barrier and we're still digging out of a HUGE financial hole, so no money for luxuries. I'm going to try Beakie's suggestion on the choice of tool.

 

[METALMOVER]

Could you just lay it on top of the rafters running the opposite way of the rafters, or do you have rafter storage?I found duct tape doesnt stick well to insulation but the clear packing tape does and
doesnt cost near as much, and I used a retractable exacto knife where the tip breaks off to keep a sharp point.Goodluck. METALMOVER

 

[OccupantRJ]

On insulation with paper backing, I used to cut it with a knife on the floor. Now I build a table of plywood and saw horses to be able to work standing, and cut it with a large pair of Wiss shears after marking with a sharpie. Wear nytrile gloves. Hell of a lot easier than kneeling on the floor, especially when you are 60+. The paper backing also does not bunch up and tear with this method. When doing repeat lengths, I draw a line on the plywood to reference length for marking. Of course, a knife can be used instead of shears if one prefers.