Undermount Sink: MDF?

| I've ordered an undermount sink for the kitchen. The worktops are | going to be granite, and the granite supplier suggested fitting the | sink to the base unit with MDF, such that the lip of the sink is the | same height as the top of the carcass. | | Has anyone had any experience of MDF in this situation? Isn't it prone | to damage by water? Wouldn't treated chipboard (or even an off cut of | the old worktop) be better?

The bit of MFD under my sink is still good after 20 years. The bit of flooring MFD under my Hot water tank, has failed drastically. I had a slight leak, which was covered by the fibreglass jacket and the tank was suddenly an inch lower than it should have been. :-( The MFD flooring under the ex-boiler needs replacing, condensation got at it. I think the bit under the washing machine needs replacing as well.

I found a piece of bathroom grade chipboard flooring which had been wet long enough for the water to have rotted the carpet grippers and soaked well up a thermal block wall standing on the floor. However, much to my surprise, the chipboard remained rock solid.

There is a piece of green chipboard in our garden which has been doing a half-reasonable impersonation of a paving slab for the last three years ;)

Lee

Whilst it will be fine with no leaks. I wouldn't dream of using anything other than WBP ply for this. At least 18mm, too.

Christian.

Hi,

If using MDF look for a moisture resistant grade IIRC it's called something like 'P5'.

Whatever you use, MDF, ply, marine ply it will all rot eventually if it gets wet and stays wet, so it's a good idea to seal it, PVA, paint, wood stain would do.

Also to check moisture resistance of MDF or ply just boil an offcut in water for some time.

cheers, Pete.