Cutting cement backer board

[Bill Webber]

Hi All,

Anyone have experience cutting cement backer board? I need to cut a piece to act as a base for tile surrounding a gas fireplace insert. I'll need to make four straight-line cuts each 48-inches or less. I know they sell fancy special purpose blades for this. What I'm wondering, can I get these four cuts out of a cheap throw-away carbide blade without hurting myself or the saw?

thanks....

[Brian Weick]

To save yourself from a complete cluster of concrete dust all over-instead take a Matt knife - put a sharp blade in, draw your cut lines- use a straight edge make a couple scores to break the mesh netting on the smooth side and then snap the board, the other rough side of the board mesh will cut much easier after the break is made- that's how you cut Concrete board :)


PS: on a side note, you may want to consider being a contributing member Bill, things are going to change for non contributing members- it's only $6.00 for the year ~ and well worth it, much more to offer for the contributors! I hope you join up with the rest of the contributing members!:)
Brian:)

[Chris Padilla]

I seem to recall cutting the cement board for my bathroom tile like Brian suggested although I think I just used a plain old utility knife and changed the blades quite a bit but I only had 30 square feet of cement board to lay, too! :)

[Bill Webber]

Thanks for the replies. I want to use saw cuts because I want a single piece, shaped like an up-side-down letter U. I'm hoping the edges will be smooth enough to accept some coloring from the grout. Yes, I'd certainly break it if the cuts were straight through and I wasn't concerned about the edges. So same question, can I get away with a throw away carbide blade? Anyone tried this?

[Jim O'Dell]

There is a special hand held carbide tiped blade to score the board with, then you snap it like drywall But be careful. I filleted (sp?) a good section of my left hand first finger when the blade road up over the framing square I was using for a guide. It cuts flesh much better than backer board!!! Jim.

[Chris Padilla]

Thanks for the replies. I want to use saw cuts because I want a single piece, shaped like an up-side-down letter U. I'm hoping the edges will be smooth enough to accept some coloring from the grout. Yes, I'd certainly break it if the cuts were straight through and I wasn't concerned about the edges. So same question, can I get away with a throw away carbide blade? Anyone tried this?

Sounds like you might want to go with a circular saw and a jigsaw or is the radius of the cut gradual enough for a circular saw?

I don't see an issue with a cheap saw blade...it'll cut it for sure.

[Jason Roehl]

You can still cut it with a utility knife. You just have to cut both sides, going over each cut a couple times. If you want smooth edges, that's what a drywall rasp is for. Seriously, any powered tool is overkill and makes one heck of an unhealthy mess.