Tiling on 18mm OSB sub floor? - Tile Advice

[Johneym]

hello Folks,

its a tiny area. 1.8 m2. Joists are solid 3 inch wide. Area is upstairs close to joists end. Have screwed the osb every 300mm. 18 mm osb. Thinking of putting on a few coats of sbr. Area feels solid but of course I cannot really control any moisture absorption or expansion/contraction. Cannot raise floor level to place ply on top. Am I crazy thinking of this or might this work? Unfortunately tiles are big, 75 x 20 cm. Advice appreciated. Thanks, John.

 

[bsc ceramics]

do not tile on OSB EVER it fail

 

[Martyn]

have same size bathroom on a wooden suspended floor, would as the OP, love to tile te floor rather than use some sort of vinyl >.<

 

[Johneym]

Thanks for replying.
Why Not tile it?

 

[Roxdec]

Use marine ply. Not OSB. Yes it’s much more costly, but it’s costly for a reason. And use matting over the substrate for shock absorption and to stop any tiles from cracking.

 

[Martyn]

Use marine ply. Not OSB. Yes it’s much more costly, but it’s costly for a reason. And use matting over the substrate for shock absorption and to stop any tiles from cracking.

So marine ply, the orange matting stuff? looked textured? then tiles would be ok for that? although my bath is similar size to the OP's the area for walking is less than half, so hopefully, would be ok

 

[Roxdec]

Yes, Ditra by Schluter is very good and there are others available too. Make sure you using jointing tape on the seams to fully seal it together. When it comes to water and leaks I am always overly careful because it can do so much damage in such a short space of time, or slowly over an extended period of time. If something happens in the future, you'll be very glad you took the extra time to do it correctly. I personally will be using the matting under the bath to seal the floor continuously, but I never tile under the bath unless it's a freestanding. If I am tiling in a side panel, I tile to the edge of the panel (bath is framed out and that frame is covered in backboard) to be tiled and then up to the lip of the bath. If you are using a bath panel, tile around 5 cm under the bath to ensure no untiled area can be seen. make sure you sit the bath at the right height if the panel is not an adjustable one. One last thing, you can use 6mm backboard instead of decoupling membrane if you need the extra height to level the floors, just make sure there is no floor movement or your lovely floor tiles will crack. I hope this makes sense. Lots of great content on YouTube if you're wanting some visuals. Best of luck.