Cutting Insulation boards

[Luton Pete]

What is best tool tro get straight edge on 90mm boards guys

 

[jeds]

Jack saw will do it, or an insulation saw will produce less dust, if you want to spend the money on one.

 

[If in doubt...]

I do the double cut like in this video :

You have to be handy with the saw but it works well for me - not necessarily dead perfect but I found good enough.

I also put the board flat on the floor on top of some old carpet - takes a bit of a knack but I find it traps most of the dreaded dust far better than having the board propped up in the air.

 

[robinbanks]

You can get saws for insulation that don't have teeth, massively reduces dust generated

They're like a kitchen knife, but with a slightly wavy edge

 

[williamglossop]

I had a load to cut recently. I used a large circular saw that cut through the majority of the depth then used.hand saw to finish...tons of dust, complete mess...... BUT on 100mm and 150mm thick board, I got nice vertical cuts everytime.

 

[Luton Pete]

Thanks Guys, Which pro cut saw is that, cant quite see the model on the picture, Has anyone used the S&J predator ?

 

[johnny2007]

I use my table saw outside.
Takes seconds and cuts are perfect.
A good hoover catches most of the dust, but a good mask is essential.

 

[Notch7]

What is best tool tro get straight edge on 90mm boards guys

festool track saw for a real clean cut and extraction limits the dust. wax blade so it doesnt snatch

or score both sides with a stanley knife and snap


if you are cutting for between existing joists or studs then a slight taper is good so it goes in snug.

 

[hllns]

if you are cutting for between existing joists or studs then a slight taper is good so it goes in snug.

Is there a good way of hand cutting a taper? I still have to finish my loft insulation job and was planning a small amount of PIR where I need headspace, a snap between two slightly offset cuts might do it but would you end up with a ragged edge?

 

[Roberto2019]

A sharp bread knife against a straight edge - 2 passes. Very little dust.

Gapotape if you want to make the job even more satisfying and lovely snug fitting boards

 

[robinbanks]

Is there a good way of hand cutting a taper? I still have to finish my loft insulation job and was planning a small amount of PIR where I need headspace, a snap between two slightly offset cuts might do it but would you end up with a ragged edge?

Put the board on a table. Put a rip of OSB (say, a foot wide) on the board. Offset the OSB relative to the edge of the table, forming the taper. Cut using the two edges (osb and table) as a guide

A circ saw with a tilting bed might be more convenient. I cut my insulation with a tilting table saw..

Not quite sure why you're worried about a ragged edge; you don't ordinarily see insulation?

 

[hllns]

Not quite sure why you're worried about a ragged edge; you don't ordinarily see insulation?

Only In so much as it might effect the fit and having to tidy it up, haven't got a circular saw so it's hand tools only for now, I've got a few thicker skip dived PIR offcuts that I picked up from a job nearby so I'll give some test cuts a go

 

[robinbanks]

To be fair, your lungs and skin will thank you for using hand tools. When I run kingspan through the table saw, dust extractor or no, the place ends up looking like a winter wonderland with the dust. Once failed to notice that the mother in law had parked her car over the other side of the garage, with all the windows down..

When I was doing my timber frame, for some of the awkward stuff I found it easier to cut the board smaller and leave enough of a gap for a expanding foam gun nozzle round the edge.. Can also cut a chamfer that is a tad wider than the pocket at the fat end of the charger, ram it in then foam up the narrow end of the chamfer