questions from new tiler

[sWe]

hi,
im new to tiling, have been doing it for the last few months and theres a few questions that have arisen. i would be really gratefull if anyone could help.

#ive only tiled floors on 2 different surfices, concrete and 12mm ply, every time ive come accross another type of timber floor ive put a 12mm ply board down and i know this is the right way to go about things but i dont know why? why can't i tile onto floorboards if the adhesive will take to it? are there any other types of floor that i can tile onto? chipboard ext? and what would happen if i did just tile streight over floorboards? (im not going to, but i would like to know) do i still need to put ply down if im also fixing those undertile heat saving boards? (raises floor even more) and why 12mm?

Floorboards are not always flat enough to tile direct on to, thats one of the reasons for overlaying wiv ply.

If yer using a backerboard you dont need to ply first.

It's not really about the flatness, though it can be a factor; If it's not flat enough, I'd argue that it's a better idea to use self-leveling compound than ply or similar.

Plying out has much more to do with the stiffness of the substrate than anything else. If the substrate isn't stiff enough, and if you're lucky, the grout cracks. If you're not so lucky, tiles can "pop" and/or crack.

(I'm not completely at home with the english terminology here, so please excuse me in advance)

Normally, you want the stiffness of the floor to be atleast equal to that of a floor where the joists have a spacing of 30cm, covered by 22mm chipboard fastened with screws every 20cm.

In older buildings over here, it's common that the spacing of the joists is 60cm, rather than 30cm. When that's the case, the tiler has to glue down floor plaster boards/backer boards with a stiffening cement based adhesive. Just screwing or nailing it down doesn't really cut it in the long run.

The tiler can also level the floor with 12-20mm self leveling compound reinforced with 2.5mm rebar netting.

Any of those two actions will reinforce a floor with joists spaced 60cm covered by 22mm chipboard or equivialent, to the equivialent of a floor with 30cm spacing of the joists.

I wouldn't recommend ply as a suitable material to tile onto, as it's organic, and might be affected by moisture, even in dry areas. Floor plaster boards are better to tile onto, as they're inorganic. Make sure to glue them down with stiffening cement based adhesive though. Backer boards are even better. Properly done leveled surfaces are the best. In wet areas, you generally want the floor to be leveled with SLC, in part because it won't deform from any moisture and it's really stable if done properly, and in part because you want the floor to have slight "fall" to the drain.

(Edit: I finally remembered the word)

An easy way to test the stiffness of a floor (I read this on the forums, great tip who ever it was that wrote it) is to fill a glas of water to the rim, putting it on the floor, and having one or two people walking around around on the floor. If the water spills, you need to reinforce the floor before you can tile it.

 

[creative]

Hi, Well... wood expands & contracts considerably due to humidity & temperature changes, floorboards move as well. Eventually alot of tiles are going to come loose even with a flexi-adhesive, ply-boarding is always essential over floorboards!

 

[wall2floortilin]

Hi daz, first things first, dont ever tile direct to floor boards! can of worms!
p5 moisture resistant chipboard flooring can be tiled to but not best practice. flexi adhesive always use with porcelaine!
joist are usually set at 16 .5 inch centres this is why we lay ply, to tighten floor up.

watch out for different screed types, anhydryte which is a gypsm based screed can be a nightmare

 

[Turkish]

Hi mate and welcome

Turkish

 

[sWe]

Heh, this thread is a month old, how come it's not locked?