Can Concrete Be Laid Over Quarry Tiles?

[richo1970]

I have a very uneven living room floor, too uneven for any self levelling compound. So the room will need to have a layer of concrete over it then i can put down some laminate floor.Can the concrete be laid over the quarry tiles or will they need digging up? Thanks.

[woofgang]

Until an expert comes along, do you know what is under the quarry tiles or why the floor is so uneven. The risk that I could see is that the floor state is not stable and will continue to move, breaking up the new concrete and leaving you with an unlevel new floor.

[The Builder]

That's a good point from Woofters. Assuming it's hard and stable under the tiles, then certainly it can be done. Whether or not you dig them up will depend on how high you want the finished floor level.

Concrete will need to be approx 50mm (2") thick at the thinnest point, and then as thick as necessary at the lowest point. That's going to raise the floor level quite a bit.

A sand & cement "screed" would be better. With a little PVA mixed in the thinnest part of the mix, you can "feather" it out to nothing on the high spots. PVA painted on to the tiles on the high spots helps to stop it from crumbling as well.

Alternatively, 2" x 2" battens could be fixed to the tiles as floor joists. Lay them level. Fix them where they touch the floor, and use wedges or packing pieces to make up the difference on the low spots.
The advantage is that 50mm "Celotex" can be laid between the battens to give you a pretty good degree of insulation over the floor. Well worth doing.

You would then lay vapour check polythene over the lot, and then wood flooring of your choice.