Cutting insulation

[sid]

I have several rolls of fibreglass insulation (about 15) to fit between joists. It's the 200mm stuff but it comes tightly wrapped in rolls of about 40 or 50 cm diameter and is very easy to handle like this. To my mind it would be great if I could cut it into 50cm widths while it's still wrapped; is there a suitable tool, or do I have to unwrap it and cut each strip with large scissors?

[Anton Redman]

Screwfix have a special knife but I used an old breadknife.

[zeb]

We used a Stanley knife for cutting rolls but then found that our local bm sold the stuff in panels so always bought that. It's not quite so nasty!

[Suze01]

We bought a special knife when we bought the insulation - it looks like an extra long breadknife and is a super-sharp, brilliant for those crusty baguettes once you've finished doing the job  [;)]

[sid]

Ah, a special knife! And do you cut the insulation while it's rolled up?

[Suze01]

I shall ask the better half who did it - I stayed well clear!!

[Suze01]

Un-rolled.

[LesFlamands]

If you can cut rolled up (same width all the way) then just use a conventional panel saw - old one is best as it does take the edge off a bit.

[sid]

I had a look at Screwfix but couldn't find the knife, plenty of conventional Stanley knives but nothing like a bread knife. I'll ask at the local DIY shop.

I thought that with the insulation nice and tightly rolled it'd be so much easier rather than trying to cut through 8 inches thickness unrolled. But what do I know!

Thanks for your replies everyone.

[DON]

Hi Sid leave them rolled up then use a panel saw to cut into whatever sizes you require you can cut through the whole roll easily ok   Don

[sid]

Thanks Don and Charles, that's the answer I wanted! I have new joists and they are very even and regularly spaced. It makes sense to me! [Y]

[hoverfrog]

we have used a 9" cook's knife to cut 200mm fibreglass when rolled and unrolled. When still rolled, you have to cut into the roll all the way round (if you see what I mean) as the diameter of the roll is greater than the length of the knife...

Saws are of limited use, as the stuff gets caught in the teeth.

When unrolled, the cook's knife is definitely the best thing, but make sure you have a plank or similar underneath!

[sid]

Thanks Hoverfrog, sounds even better.

Sid

[Dave&Olive]

hi

             we had a gift about 15 years ago ,a leccy bread knife ,the only thing it`s ever been used for , yes you`ve got it right ,to cut up rolled up rolls of..............

                           dave

 

[expat paul]

Hi,

I've found the best way is to cut them rolled up using a hand saw. I have a saw for plasterboard and has teeth missing so it doesn't get clogged up. You can find them at all the DIY sheds either a scie plaque de platre "jet cut" or a scie de batiment  its much easier/quicker than a knife because they are 550mm long.

 

Paul

[sid]

Dave, I like the idea of putting an unused gift to work... the electric breadknife! Unfortunately we haven't got one [:(]

Paul, others have suggested a saw but I imagine the teeth pulling and snagging the fibreglass strands. Are you saying that because it's tightly rolled it works OK? I can see the advantage of using something 550mm long and the cut would be more accurate too.

This started out as a simple query and I'm getting obsessed with it!!! [8-)] I'll go and check out the saws in the local DIY, I've got a little time yet before I start work on the loft.

The forum is great, isn't it, plenty of feedback.

[expat paul]

Sid,

Sorry for the delayed reply, computer problems[:(] , however better late than never.

Last year I had to cut around 100 rolls of the nasty itchy stuff and I found using the plasterboard saw they cut OK. I think whatever is used will snag to a certain degree, but, as you say when rolled up it wasn't too bad.

 

[sid]

Thanks expat Paul.