Can Durarock be routed?

[Rich Engelhardt]

Hello,
I'm putting ceramic tile in a bath.
The bathtub is one of the older styles with a contoured profile.
I'm going to be taking the old plywood subfloor off and putting on a new one.
I have a pattern already made up so I can route the profile on the plywood.

Before I destroy a $7.50 sheet of Durarock by trying it, is there any reason I can't use a cheap straight router bit to route the profile?
Other than the dust & destroying the bit that is.

[Julian Nicks]

Simple answer. NO!!! Durock is a concrete board, and a standard router bit won't do anything but dull immediately. Just score it with a knife and crack it just like you would with drywall.

[Rick Hall]

You can also mark the profile and cut it with a dry cut diamond bit on a 4" or 4 1/2" angle grinder, or even a circular saw if the profile isn't too detailed. I've never had great luck with score & snap breaks on dura-rock for anything but straight lines. Make sure to wear a dust mask and do it outside if you go this route. It will be messy.

Rick.

[Lee Bidwell]

I know you're not supposed to cut the stuff, but I just finished my kitchen backsplash, and I cut out all the holes for plugs and switches with a jigsaw (didn't feel like picking up a rotozip or other multi-tool). Of course, it dulled the blade to the point where there were no teeth left, but, who cares, it's a jigsaw blade. As mentioned above, if you do cut it, wear a good respirator. The dust can be carcinogenic.

[Michael Poller]

We just laid down Hardi-backer (cement board - just different brand than duorock) and tile in our bathroom as well.

I tried to route the circles using my dremel similar to what you suggest and the smell of burning metal and concrete stuck in my nose for days!! Took all of a literal second or two for the bit I was using to burn up in the concrete.

Best thing I did was buy a small diamond wheel for the dremel tool. Made cutting circles for the plumbing lines and such an absolute breeze.

If you have a rotary tool, get the diamond wheel for it and it will work wonders for matching those curves in the cement board. I have no need for expensive diamond edged hole saws and such as I'll likely never use them. But the diamond wheel can cut so many things it will come in handy in the future.

I actually also used a large size diamond wheel for the dremel tool to cut the circles and any non-staight cuts in the ceramic tile we laid down. Worked awesome and for the few cuts I had to make like that (7 tiles total) way more economical (wheel was $20) than buying or renting a wet-saw, new or used.

Oh, if you do it inside like I did (it was raining that day) definetly set up a shop vac or something so it will suck up the dust it creates, and I also wore a dust mask as well as that stuff is nasty.

For straight cuts 5-8 hard score cuts with a sharp utility knife does the trick.

[Eric Meier]

They actually sell a jigsaw blade with a carbide grit coating. IIRC it actually did a pretty good job on the backer board. Do a search for "Remgrit jigsaw blade" and you should see what I'm talking about. I think I got mine at Menards.

[Dennis McGarry]

Also the jigsaw blades for cutting tile will work great with durarock as well. As will the circle cutters for the same..

[John Gregory]

Use a jig saw with a diamond coated blade. It worked for me. Way less dust the way.

[Rich Engelhardt]

Hello,
Thanks!
My turn to say "Thank goodness for the wealth of been there/done that" here at SMC.
I'll be picking up a diamond Dremel cutter and a diamond jig saw blade.

[Michael Poller]

Just happy to help someone else avoid the blood, sweat, tears and often cursing that I might have gone through before figuring out the smart way to do it...

Can't image having tried to cut a circle in cement board with a utility knife alone.

[guy knight]

having cut and installed several thousand sheets of durarock/wonderboard allot of guys use diamond blades on grinders works good but is slow i have always used my skillsaw with a normal carbide wood blade on it cuts like wood fast easy and that relates to more footage installed in a day and more money in my pocket

[Fred Foss]

Hello,

Before I destroy a $7.50 sheet of Durarock by trying it, is there any reason I can't use a cheap straight router bit to route the profile?
Other than the dust & destroying the bit that is.

they make a carbide tile cutting blade for the rotozip that works pretty well, I bet that'd cut it ok. get the 1/4" one. you could probably use in a router but the dust might kill your router

--fred

[Rich Engelhardt]

Hello,

Well- I did use the router, but not on the Durock.
When I ripped out the old 3/4" plywood subfloor, the original builder had gone to great pains to fit it to the contour of the tub. I really took my time getting the section out in one piece.
Using a 5/8" insert & a 1/2" straight bit I was able to use the old piece as a template and routed a new piece of 1/2" plywood for the new subfloor. I switched over to a top bearing straight bit and cleaned up the cut on the new piece.
It fit like a glove.

I used the new piece as a template and traced the outline on the Durock.
Using a diamond wheel in the Dremel, I was able to zip through the Durock in no time flat.

My only mistake was to score that piece and break it ala drywall. I'd done that before, and while it works, it leave a rough crumpled edge.

I decided to sacrifice a $20, 40T Diablo blade to the "cement gods" and stuck one on my old Skil circ saw.

Wow! What a great smooth cut! Quick and surprisingly a lot less dust than I expected.

I'm going to be laying out the 10x14 dining room area today and since the Durock comes in 3x5 sheets, I'll have a fair amount of trimming to do.
We'll see how long the Diablo holds up.

P.S. The advice about a respirator is spot on. Since I was working outside, I tried to get by with just a dust mask for the first cut. One little cut convinced me to go out and buy a 3M respirator.

Thanx for all the help on this. It's turning out pretty well - so far.