How to prepare bathroom floor to take tiles

[TanDiy]

Hi, I hope this is not a stupid question. I am thinking of tiling our bathroom floor and went to a large tile shop for advice. They said that building regulations states that the floorboards must be covered with 15mm ply wood and then the tiles placed on top. However, they supply a special waterproof board that is better because it is fully approved for building regs and is only 6mm thick.

Now I might be missing something but, 15mm of ply with tiles on the top - surely that is going to produce a small step up in to the bathroom. Bathrooms I have seen do not appear to have this - the tiles are nice and and low to the floor. Is the shop giving me duff advice or am I being thick. Thank you

 

[PrenticeBoyofDerry]

You could well end up with a step between floor coverings.
This can be over come by feathering an edge to door opening on other floor surface. But the floor covering would really need to be carpet to hide the slope.

 

[Maxsys]

Suggest you read the tiling sticky, and search the forum, this has been covered loads of times. 15MM is the minimum BS spec for overboarding, however you may get away with less depending on the type of floor you have now, the size/pitch/span of your floor joists and the type of tiles you intend to use.

The problem you are trying to overcome is deflection, or bounce in the floor.

You could rip up the old floor completely and put down 18mm or 25mm WBP ply, but like i say this will depend on the information above regarding your joists. Post that and we can offer a much more detailed answer.

 

[Richard C]

Your tiling shop is spinning you a load of ballrocks about over boarding being a Building Regulations requirement, there is nothing in BR’s that stipulates floorboards must be covered with anything at all before tiling but if the floor isn’t rigid enough, the tiles will quickly fail.

The British Standards, Tiling Association & all the adhesive manufacturers I know of specify 15mm WBP for overboard, however 12mm is usually sufficient & in light load/use area such as a bath/shower room, depending on your floor joist ssize/pitchy/span; another alternative is to use a decent tile backer board. But if the original floor is chipboard your better of replacing it, it’s crap.

I would strongly advise you read the Tiling Sticky & Forum Archive posts before doing any work or buying materials, it could prevent you making disastrous & potentially expensive mistakes. When tiling or re-tiling, there are many things that can catch you out. With walls, you need to consider tile weights, prep & materials & suspended timber floors need special consideration. It’s also important to use only quality trade tilling materials of the correct type for your tiles & tile base; cheapo own brand & DIY stuff is mostly crap.

 

[TanDiy]

Thank you very much indeed for the replies - really very helpful.

 

[prceramics]

cement backerboard

 

[tictic]

Secure/screw the existing floorboards to joists,then 6mm hardie backers boards glued and screwed....stagger them.