hi all , looking for a little advicehaving rushed into a big tiling job (for a novice like me!) ie my whole bathroom, i stuffed up on the floor , grout cracked up fairly badlyanyway i am using a flexible quick-set adhesive and grout(both flexible) brand-'bondmaster'i have just done the floor when i got the cracks and decided to hold off on the walls before i know more.tiles 300x600x9mm porcelain laid on 12mm wbp plywood screwed to 20mm floorboards at 150mm centres.3mm tile spacing (floor area is only 1.1mx1.8m) i thought the 12mm ply would b enough having done my kitchen some years ago with 12 even though it is bigger and never a prob.i was probably a bit gung-ho mixing up the grout and added too much water. anyway i was able to cut it out with a stanley after a week- this sound like it was way too soft for a flexible grout to anyone who fixes other peoples mistakes.so to get to the issue to b on the safe side i have purchased another grout: bostik(evo-stik) tecnik sgs(special grout system) which is flexible. being a bit unsure i visited their website for some teccchie info and notice they also do a flexible grout.sorry to b so long winded , what i would like to know is the sgs good for this job or would the flexible be better.any advice greatly accepted

sorry i never use bostik products,

the one for me would be mapei ultra colour or bal super flex

12 mm ply is not thick enough , even though you got a way with it in your kitch

The bostik SGS looks like it is suitable for your floor but I have never used either. As above I would go with Mapei as IMO they are the best on the market.

12mm isnt think enough and you need to find out if it is a problem with your grout or the bond between the tiles and the substrate. In most cases, when the grout starts to crack you can be pretty sure that the tiles are going to start to lift and crack soon, and this of course wont be fixable with any grout.

The Bostik looks like it's packaged in the same bag as Biscem, used once.

we use the bostic products here in northern ireland a lot of tile shops supply it (sgs) i never had a failure with it i would probably go with the mapei myself if i had the choice but use it it will be fine its certainly flexible for what you need!