Installing pink insulation question??

[Rick Moyer]

I know you are not supposed to compress the insulation (e.g., packing
R-19 into 2x4 studs), btu what about the width? My new house has the garage studs not evenly spaced. Most are 16"O.C. but many are anywhere from 11"O.C. to 18"O.C.
Can I stuff 14 1/2" wide into a 10"-12" wide spacing betweeen studs, or do I have to cut the roll lengthwise to fit between? I know the right way would be to fit it correctly but how much would it hurt to do it the other way?

[Jim Becker]

You should cut the insulation to a width that is about 1/2" or so wider than the opening so it fits in snugly without gaps. Do not cram a full batt into a narrow stud bay. It will not be as efficient and is a waste of material. When I was in the business, I tended to do all the cut pieces first and left the full batts for last.

[Chip Lindley]

The accepted method would be to cut the insulation lengthways to fit width between narrow studs. If studs are wider than the insulation roll, cut extra to fill the gap. Insulation only works when it is installed as intended. Cramming extra smashes out the air and reduces its value considerably. If you leave voids, cold or hot air easily infiltrates the gaps. Plastic sheeting stapled over all provides a vapor barrier beneath the wall material you choose. Since it is the attached garage of your new house, I would think you want to do this right the first time!

[Rick Moyer]

I guess I knew the right answer. I was wanting it done asap as it's pretty cold out there but I'll do it the right way.
Any suggestions as to the best method of cutting the batts lengthwise?

[Jamie Buxton]

If you've already bought the fiberglass, this suggestion to too late. However, sprayed-in insulations like icynene or cellulose don't care at all what your stud-to-stud spacing is. They also provide better R value than fiberglass.

[Rob Russell]

I guess I knew the right answer. I was wanting it done asap as it's pretty cold out there but I'll do it the right way.
Any suggestions as to the best method of cutting the batts lengthwise?

I have a pair of really huge scissors that was in a box of tools I bought. The blades must be 8 or 10" long - those work pretty well because you can cut a neat line.

[Jim O'Dell]

I lay it on the concrete floor, and use a long ruler. I have a 5' aluminum one. Cut it with a sharp carpet knife. You will end up with out a flange to staple with, but shouldn't be a problem. If 1/2" oversize like Jim B. said, it should stay in place by itself. Jim.

[Jim Kountz]

I do as Jim B said and do all the full batts first. For openings less than standard, just place the batts in the openings snug to one side and let it lay over the next stud. Use the stud to make the cut, cutting right down the middle of the stud. This is a no measure simple way to insure the batts are the correct width. Simple and easy. Our guys do this all the time and its quick.

[Bill Houghton]

I lay it on the concrete floor, and use a long ruler. I have a 5' aluminum one. Cut it with a sharp carpet knife. You will end up with out a flange to staple with, but shouldn't be a problem.

Almost ditto, but I have found that, with a light hand, I can cut the fiberglass almost to the stapling flange and then peel the glass off the flange.

NOTE: you probably know this already, but wear a GOOD dust mask. Some people wear long sleeve shirts and gloves - though not everyone's sensitive to the fibers (I'm not).

[Matt Ocel]

at about three times the price

[Les Zielinski]

I recently insulate my garage with DOW Safetouch insulation. No need to use gloves or long sleeves shirt. It does no itch! I had to cut it longwise too. I build a simple jig to do it. Insulation comes only 15" wide. I plunge cut a piece of plywood, installed two 2X4 on the bottom and 2 2X4 on the top to create a 15" "channel" with the plunge cut in the center. (In my case I had to split 15" insulation into two 7.5" long pieces. I used a very sharp kitchen knife to cut the insulation positioned in the "channel". Worked like a charm.
The only problem was Safetouch insulation. It is only available at selected Lowes stores. It took me some time to get it to one of the local stores in Florida but in the end it was worth it
Les

[Lee Schierer]

It's good that it is cold in your garage when installing insulation. You won't sweat much and that means your pores won't be open for the fiberglass to get into. When you go to wash up, wash with lots of soap and COLD water. The soap will get the glass fibers off your skin and they won't go into the pores because of the cold water keeping them closed.

Wear a dust mask and safety glasses to keep the fibers out of your lungs and eyes.