Hi, got a job to tile upstairs bathroom floor. problem is theres chipboard all over with a small dip and bounce by the door. A builder friend i know said i should screw ply down and then use leveling compound,is this right? forgot to say cant take chipboard up and replace with something else as it goes into another room.
also what adhesive should i use with slate on floor??
any advice appreciated,
andy

Is it possible to cut the chipboard along the wall and remove? Ideally you want to remove it, replace with as thick WBP ply you can get away with (min 18mm) after sorting out any deflection with extra noggins and then Id over board with a backerboard ontop of that. This will give you about as good a substrate you can get to tile onto. Some people tile straight onto chipboard (I dont) but if there is movement in the boards it must be sorted before you tile. Slate is very soft, it will have to be cut with an electric cutter. You will have to work very clean, washing off any adhesive off the tiles as you go and the tiles will have to be sealed.

i was going to just cut out and replace but the customer wont let me for some strange reason. i think there hiding something maybe??

Originally Posted by andyet

i was going to just cut out and replace but the customer wont let me for some strange reason. i think their hiding something maybe??

Its not a body is it?

I hate customers like this, could you not try fastening bounce down and overboarding with NMP or 18mm wbp. By the sounds of it they won't like the step either and will probably say 'well my uncle fred says it does'nt need doing'. If this happens tell them to let uncle fred do it.

Hmm... As I said above, even if you want to tile straight onto the chipboard, something has to be done about the movement and you will need to get under the boards to do that. There is no way Id tile onto a floor like that, the tiles will lift and crack Im afraid. Try and explain this to the customer. How much deflection are we talking here?

My above posts are assuming that the boards that are on the move can not just be screwed down?

I'd tell them how strongly you feel about it and if you can't do it properly you won't do it. Hard to do i know especially in these times. Hopefully the fact you are risking losing the job will hit home to them and they will let you get on with it. The last thing you want is them ringing you in a month complaining.

the chipboard that is bouncing seams to have nothing supporting underneath looks like its tounge and groove that hasnt been pushed together proply.
ill go give them another try tomorrow, if they dont let me pull them up ill just have to asume that there is a body under there and run for my life
cheers for all the advice guys

How do you know if you screw this boards down that there are no pipes or cables too close to the underside of the boards? There shouldnt be but ????

Good point Ramic, if you try drilling into the boards use a pipe detector.

They dont detect plastic pipes though

Best to screw as close to the existing nails as you can, assuming of course you cant get the nails out? I assume they will be ring shanks, if they are forget trying to get them out.