Tile – Cutting Ceramic Glass Glazed Tile

Here are some good points against using plywood, the source is talking about tiling a floor but most of the points are valid for walls as well.

In my opinion it's better to go the "overkill" route, then have to redo the job in the future because something didn't turn out right.

The cost difference between plywood and cement board is negligible, so your not going to save any money using plywood (unless you already have it).

Do the job right and use cement board, when you don't have any problems and you can enjoy the tile for years to come you will never regret the decision.

For cutting porcelain or ceramic tile, standard practice is to use:

• A wet saw with a diamond blade
• A manual tile cutter (a carbide wheel slides along a rail to score the tile, then you snap on the line.
• Tile nippers for complex shapes

You can use a diamond blade with a hacksaw to cut holes, but it won't be very efficient.

If you have mostly straight lines, you can get away with a decent manual cutter and perhaps a pair of nippers. A wet saw makes the job go faster, but is not necessary.