Tiling kitchen floor

Hi there,

I have to tile a kitchen floor which will be an area of approx 35m2.

Currently the flooring is chipboard sheets, which I know it isnt really a good idea to tile on with ceramic tiles. I found a website which says that it is fine if you cover the chipboard with 6mm plywood. I assume this is correct ?

The tiles wont be particularly heavy (but typical ceramic tiles) but with hte area, there is obviously quite a weight on there. In addition the kitchen which is being installed has an island unit with a big slab of granite on top.

Since there is a cavity of (I believe) a foot or so between the joists and the earth under the house, a friend suggested that it might be worth supporting the joists with breeze blocks (spelling ?) or similar. Is this a good idea ? Is it necessary ? Obviously it means taking the floor up at least in part and crawling around under the house which I wouldnt really relish !

Thanks

Tim

Doesn't sound to me as though you would have to add extra support for the joists if all is OK, but while you have everything up, it might be worth lifting a few chipboard sheets to check that settlement has not opened up gaps between the joists and the sleeper walls which support them. If there are lots of large gaps, you can often tell by a springy feeling in the floor, especially in the middle of the room. I dare say you can't feel smaller ones unless and until they get bigger. Gaps, if any, can be packed with pieces of slate or various other materials - google the group for tips. Well worth doing if you need it. I would feel happier doing this than trying to cope with any springiness by adding sheets of thick ply (though 6mm ply over whatever you already have sounds a good minimum for ceramic tiles). And don't panic about settlement unless the rate is high - parts of my house have settled several mm in 10-15 years, but there's nothing to suggest a major problem.