View Full Version : Advise desperately needed

7th Mar 2005, 10:36 PM

I am currently building a double storey house. I noticed the tile layer person has just layed the tile over the MDF floor board without sanding MDF floor board or put cement sheet over the floor board. I am concern that the tiles will break in the future when weight are put on because the MDF floor board might not be evenly flat. Would this a normal practice in the trade? or is the tile layer person is cutting corner? Is there an industrial standard for this?

Please advise. Thank you very much.


7th Mar 2005, 11:51 PM
MDF is okay as long at it fixed flat and stable to whatever is underneath it. Maybe check what thickness MDF he is using, i'm not sure there is an industry standard but I think 12mm or less would be too thin.

Is it a wet area?

Document about Tile Fixing (http://www.justtiles.co.uk/tilefixingguide.pdf)

This is a document which talks about File Tixing and recommends not using MDF - go figure!!!

8th Mar 2005, 08:27 AM
I thought tiles had to be laid on 6mm tile underlay (cement sheet) which is nailed at 150mm intervals to the chipboard floor. That's what the guy did here anyway on our new bathroom and also through a new house I had built last year.

I think a bit of cost-cutting is going on.

8th Mar 2005, 09:00 AM
I dunno about the backing - I laid tiles on superfloor direct with no probs BUT make sure also that they are using flexible tile adhesive and grout, to allow for movement.

8th Mar 2005, 09:03 AM
It's not unusual to glue tiles directly to a chipboard floor. They make a tile adhesive with a PVA additive that creates a flexible bond so that the tiles don't come loose (although they still do from time to time). Personally, I'd rather see a tile underlay glued and nailed down first but I don't think it is strictly necessary. The tile underlay is designed for use over floorboards.

Not being an expert on current building products, I'm a bit surprised to hear that MDF would be used for flooring. I'm not saying it isn't, but are you sure it is MDF?

If it is a wet area then the guy who laid the tiles is a moron.

8th Mar 2005, 03:43 PM
I agree about that MDF reference. I'd be surprised if that's what it is.

Wouldn't one advantage of tiling on to cement sheet be that it is easier to pull them up again later. Just pull up the whole sheet rather than chip each tile off separately.

9th Mar 2005, 06:06 PM
Hi Wes AS 3958.1 describes the industray standard installation of tiles on a wooden floor.

Framed floors (as opposed to suspended concrete slabs) are only allowed in residential applications. The 3 options are
1. direct tiling onto a wooden (usually ply or particleboard) floor
2. using a FC underlay sheet minimum 6mm thick.
3. tiling onto a structural FC sheet 15mm thick (hardipanel)

In all cases a flexible organic based adhesive should be used and the floor should have a deflection less than 1/360 span.

The particleboard should be 19mm thick also.


12th Mar 2005, 10:44 AM
Thanks guys... very appreciated your advice.