Cutting Underlayment

[Matt]

Hi, What do I use to cut underlayment for under tiles? Will a knife work? Or do I need something more agressive like a saw?

~ Matt

[Charles Spitzer]

what are you using?

if it's wonderboard or it's ilk, you can cut it with a masonry blade in a skilsaw, or you can scribe it using a carbide scribe and break it over a

2x4, for example. a knife won't cut this material. if you're using something else, you have to tell us what that is because we can't see it from here.

[Pat]

I use a knife for the straight cuts and a jig saw for holes and notches.