I need to install an electric fan is a tiled bathroom wall. It requires a 4" ventiliation hole. I am very concerned at the risk of cracking the tiles. Is there a way to minimise the risk?

David, October 2007

You need to break the glaze on the tile first.
Put some insulation tape over the spot where you want to drill. This will stop the drill from slipping, then place the drill bit against the spot and twist left and right a few times to break the glaze. Now use the drill to drill through. Dont use the hammer on the drill until you are through the tile. Or buy a drill bit especially designed for the job...Spear bit I think they're called.

Alex, February 2008

Here's a tip. Mark when you want to drill and a stick tape over your mark. (A couple of layers of tape is best.) The tape gives the bit something to grip on to stop it sliding across your tiles as you start drilling.

Bob, November 2007

what about cieling fan and exhaust through soffet board,if not its a 4" circle in felt pen tile drill from b@q holes closley together and gently break tile middle and hire 4"hole cutter from hire shop sleeve hole to stop moister into cavity and fit fan,good luck
ross

ross, November 2007

You really need to use a diamond core drill. These can be hired from most tool hire companies. A TCT core drill will cut through but the increased vibration can cause cracking. When using the diamond core bit, be sure to use only light pressure and low speed, about 200-300 rpm and start the hole level and straight as altering the direction after about 25 mm penetration can cause stresses on the edge of the hole.

Terry mitchell, October 2007