I just bought a nice piece of 1/2 inch backerboard (Hardieboard?) to repair the lower half of my shower, where some tiles were coming loose. I measured the size pieces that I needed, scored the board nice and deep, and went to snap it, just as I've seen in several videos. AND.....

The bugger crumbled elsewhere, and not on the score line.

So: HOW in the name of God's Green Earth do I get this stuff to snap where I WANT it to snap? I really don't want to have to use a saw, because I don't want to crumble the board edge, stir up a cloud of silica dust, or dull a bunch of blades. I can't afford $120+ for a pair of cement board shears that I might only use once or twice. I see other people on line snapping this stuff. Why won't it do it for me?

I tried taking a waste piece and scoring it even more deeply. No dice. Useless random shards. What is my error?

Insult to injury: Behind the old cement board that I took out was....insulation?? And a few smaller studs, but nothing standard. The oldf board was secured by 2 1/2" nails. Really?? Arrrgh!!!

Help would be greatly appreciated. Thanks!

-kes/ff

 

Welcome to the forums!

I have never tried to snap 1/2 Hardie (and I'm not going to) and I bet it is pretty tough. Go buy yourself a fiber cement blade for your circular saw and cut it with that. Cut it outside with a mask and you will be fine. They are only $14 at big orange.

I bet in the videos they are snapping 1/4"

 

I had the same problem. I bought both 1/2" and 1/4" hardiebacker. The 1/2" board was very difficult to snap. It only really worked when I was snapping a large piece with more leverage.

Make sure you are scoring on the front and then bending it towards the opposite side. For the smaller pieces, I ended up having to measure and score deeply on BOTH sides to get it to snap.

Hope that helps.

 

I'm with Tolyn on this though I usually used a diamond blade. The masonry blade works fine though. I guess the price has went up since I bought one. I remember the price at less then $5 for a masonry blade. As to the diamond blade it was just used because it doesn't get used up when you cut with it and it was really a general purpose blade I used on many things from ceramic tile to brick to concrete blocks. I would never try scoring something that costs as much as backer board. I know some book probably told you to and the book was probably written by someone who had read it in a book and never actually done it.

 

Cutting through is the way to go, but if you really want to snap it, try putting the board on a workbench (not the dining room table, or so the mrs tells me). Line up the score line with the edge of the tabletop, then bend the board down, using the table edge to help guide the break. Snapping works great on 1/4" but you have to cut really deep on 1/2" to get a reasonable snap.