Ceilings Are Harder

Just started to do the ceiling installation.


That’s Untratouch r-19 insulation 24″ framing. It’s not as easy as fiberglass for sure, but for what i’m doing i think well worth the effort. Here are some issues should you try this yourself.

Cotton batts are heavier then fiberglass so when you install them you kind of wedge them between joists. For me this presents a bit of an issue. For one my framing is irregular so I will need to cut the insulation more.

Cutting this stuff is harder then fiberglass. With fiberglass you can compress it down and use a utility knife. A few strokes and you’re done. Cotton is harder to cut.

I’ve tried several things.


The best solution I’ve found is to use a utility knife or maybe it’s called a drywall knife. The Bonded Logic site recommends the same. Basically a razor with a handle. Hold batt in place and cut repeatedly. Not a super clean cut but i don’t think you need one. Make sure you have extra blades as they get dull fast doing this.

Other items I’ve tried. The “insul-knife” (3rd from left in image). This costs $40 and is slightly better then using your mind and willing the stuff to cut itself. To be fair it’s possible I got a used one from the hardware store as this thing is just not very sharp. They sell a sharpener for it…but I still can’t see how it would work better then the utility knife. I’ve also tried my wife’s Global sushi knife (1st on left in image) (We don’t make much sushi around here but I don’t think I’ll tell her about it) a hack-saw, a wood saw, and regular scissors.

I just kept looking for a better faster cleaner way to cut it. Now I’ve given up. The Bonded Logic site has a few more suggestions involving circular saws, grinders, and table saws. Since i’ll be installing about 400 square feet I may try out my grinder and circular saw.

Alternatively, if you really don’t care about a clean cut you can tear it. This actually works pretty well but you have to pull it apart rather then try and sheer tear it.

Lastly on the cutting front there is a saw like tool (Bosch Foam Rubber Cutter) featured on the site. Looks usable, but not worth buying unless you cut lots of cotton batt.

OK, the trick. Cut it, then wedge it. But wedging is hard on a 24″ span. Those of you with 16″ O.C. framing will have better luck.

Even after my miraculous wedge engineering (Serious, I had to try some pieces 4 times) the batts should be held in place with something. I’m curious to see what falls overnight since I don’t have any netting at the moment.

Now lets’ talk about blue cotton fallout. Wear at least one of those dust filters when installing this. You know the kind everyone was wearing for SARS and later Swine flu? Cover your eyes if you are installing overhead because you will get a healthy blue dusting. I’ve been wearing a respirator.

This stuff is pretty green. It’s basically cotton with a borate added. Borates are nice things. They help with the laundry, kill pests and mold, and retard flames. All that and they aren’t very toxic. Wow.

I just finished putting up one bail. I so wish I took some acoustic measurements when I started this whole process. After I finish I will take them. I hope to see a flatter kinder room.

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