[Speedball]

How would you cut the fiberglass insulation if it had to be cut on an angle?

I wanted it to be the same angle to parallel the pitch of the roof so it does not block air flow from the new soffit vents I just installed all around the house.

I thought about purchasing a wavy edge knife from a home store but didn't feel it was long enough or would cut nice and smooth. I also have a 30 year old pair of 12" long scissors that belonged to my Dad but they may not be the sharpest.

:whistling2:

 

[yummy mummy]

Use a 2X4 and a very sharp knife.

 

[Scuba_Dave]

Yup, piece of wood to flatten it down & a sharp utility knife
Take care at each side where the paper is folded over

 

[DangerMouse]

if i understand right, the knives won't do it. trim carefully with long scissors, (if you're cutting just the insulation on a bevel.)

DM

 

[Maintenance 6]

That's the way I cut it. A big ol' shears that looks like it came out of a tent factory.

 

[RippySkippy]

It's one of the few times I like to use the Stanley snap blade knife...I don't like trying to mash the insulation to the point of cutting it with a utility knife...

 

[Speedball]

Thank's.

I'll try some different techniques and see what works. Now I wonder if someone local has some new long scissors if the razor knife and 2X4 doesn't work.:rockon:

 

[Scuba_Dave]

I've never had a problem with a razor knife

 

[SNC]

Yup, piece of wood to flatten it down & a sharp utility knife
Take care at each side where the paper is folded over

Yup this is the way, a good pair of sissors works real well also

 

[James Con]

Non serrated hedge shears work great, Cuts like butter.

 

[DangerMouse]

still confused here.... are you cutting a full piece at an angle or are you trying to trim an edge?

DM

 

[creamaster]

When I did my attic I added unfaced R 19. I used a bread knife and worked like a charm although the wife wasn't too happy at the time anyway until that winter when she just loved the extra warmth in the house, so all was good then

 

[Chemist1961]

Speedball, you want to retain full depth insulation above your top plates. To assure air flow above that you can purchase a 4' long egg crate type baffle which is stapled to the underside of the roof approx every 3 rd joist space.
A serated insulation knife or a bread knife will help with your cutting but insulation above must cover the top plate fully to insure a warm wall below and ceiling at the wall