small rock ok floor tile??

hi after starting to tile my bathroom it turned in to more than 1 job, the floor around bath,sink and toilet pan were swollen.

the floor is chipboard,the rest of floor looked ok, so i removed these parts and replaced them with same chipboard.

i lay down my plywood(6mm) and screwed it down at every 200mm distance (boy thats a lot of screws).
ive took door of and when dry laying the tiles , just at corner where door is theres a slight rock,( from top right to bottom left), its about a 2-3 mm ( i can fit a plastic school ruler under it) and its only at 1 corner.

i checked the floor and its where the floor comes in under the wall and joins to the hall floorboard (chipboard t&g)

and to lift al that is a major job. will the adhesive correct the rock if i use a little more or will the recomended spread be ok. the tiles are ceramic and the adhesive is Bal Rapidset Flexible... any advice welcome..



(update) i drylayed a few tiles and without cutting them to shape, they also have a small rock in them, just a few tiles, is this a normal characatristic of dry laying tiles and easy overcome, man if tilers have to pull up floor all times i dont envy yous

6mm ply is no good to tile too.... and your choice of adhesive has no guarentee on that substrate..

What made you use 6mm ply..?

hi , the adhesive was recomended by topps tiles , i used 6mm as i read alot of places it would be ok to use,and wouldnt bump the floor up too much.what grade ply should i go for? 9? i also have evostick floor tile adhesive grout aswell ,

If you want to keep the 6mm height th en use 6mm hardi backer....the thing is with 6mm ply is that it isn't stable enough with moisture and can even buckle with the water from the adhesive, for what good it is you might as well just not use it...

Sorry to say this but deffo no good to use....do some searches on here and see other replies..

Originally Posted by G1zm0

hi , the adhesive was recomended by topps tiles , i used 6mm as i read alot of places it would be ok to use,and wouldnt bump the floor up too much.what grade ply should i go for? 9? i also have evostick floor tile adhesive grout aswell ,

Where have you read that ?

hi thanx for advice, i will lift the ply, what mm should i use, whats the minimum?. so should i take the bal back to shop and get another kind?

ive searched that much forums and it sayeed it on one of them, something diy i think and the tiler from b&q sayed 6mm is ok .

i wil need to get the new bits cut to size so it can fit in my ford focus, so far i have 3 pieces down, easyer for the tricky cut outs and the amount room ..

BS is 15mm but you may struggle to find it so 18mm is readily available. Make sure its WBP Ply and not construction/shuttering ply.
Adhesive is fine.

would use 15mm ply also but as you say height is an issue then i would opt for 6mm hardiebacker,there is not much difference in price with the ply

i see topps do the hardy board, will the 6mm hardy 250 be ok to lay(£12.50) instead of the ply(dump the ply ive got ) or should i go for the 12mm hardy 500 at just £1 dearer.

is it easy to work with and cut?

Originally Posted by G1zm0

i see topps do the hardy board, will the 6mm hardy 250 be ok to lay(£12.50) instead of the ply(dump the ply ive got ) or should i go for the 12mm hardy 500 at just £1 dearer.

is it easy to work with and cut?

If your sub floor is sound then 6mm Hardi will be fine. If the floor has any bounce then Ply will add more strength than Hardi backer boards. Remember to secure your sub floor to the joists first too add strength.

Cutting of hardi in straight lines is no problem with their scriber but cuttting around shapes are tricky. I use an angle grinder myself or a rotozip.

thanx for reply,is a jigsaw anygood?, the floor is secured to joists, i made sure of that ans replaced a good few parts and where the board was only secured using the t&g (not supported by joist) i added a bit wood and nailed it to it so no bounce.

will the hardi do away with my original prob of the rocking tile? or should i bite the bullet, lift all the floor and redo with 18mm ply then i can tile straight onto that?



when you guys add the additional hight, what do yous do about the difference in floor height between the hall and toilet?

a looked at the bridges that hide a the joint of carpet to tiles but they are for flat surfaces not a stap of 18mm???


lol prob would have been cheaper getting someone in to do it, spent over £300 on wood, tools ect

i read theres an alternative to the hardi board, called no more ply and its easy to cut, but need special glue and nails to affix it?.

i was trying to see where the resellers of this product is based around galsgow area.

for under £8 compired to the price of hardi is good, keep costs down

No More Ply is similar to Hardibacker but as you say it is fixed with special adhesive and a few screws. I actually use it as my local tile outlet stocks it.
This rocking tile ?? Does it rock on the original floor? , if so you need to sort it out 1st. Laying a covering may not help you over that problem.

As for the jigsaw, the boards will render the blades useless pretty soon.

the original floor , yes i think it does with the rocking tile, its where the 2 chipboard t&g meet, one comes in from hall to bathroom about 4 inches and the other comes from kitchen and joins it.

and the joint where the hall and b/room meet is where the rock is, the walls were installed after the floor was down i guess as the boards run under all the walls.

only think i caan think of to solve it, is empty bathroom and lift up old floor, and where it runs into other rooms . cut it at the joist and nail a new joist to support new floor panels. and put in noggins as well then fit new floor.

i take it shanked nails will be ok to nail floor to joists as they are grooved so they cont come out easily??

then after that it should give nice surface to tile to without lining it.

if i make a few short cuts like 6mm between a board will it b on to tile over thisor should i fill it with filler like no more gaps expanding foam..

if i had hair i would rip it out lol

Can you not plane or sand this area down to get rid of the problem. Then over board with no more ply.
I would use screws mate, dont under estimate the strength of adhesive .

the rock is about 2-3mm, what would yous solution be to this problem, have to get it all done for sun, wife is staying at sisters as ive took toilet out lol

Just get rid of the rocking part by planing or sanding that area then over board with Hardi or No More Ply and then tile..Job done.

will give it a try sanding it , would the hardi or nomore ply (unsure where to get this near glasgow, nothing comes up in google) take out the small descrepancy of a mill? is there no leway in tiling ?

Use hardi, its stuck with tile adhesive which can be built up a little to get over the problem.
Depends how fussy you are, you could self level with Mapei Fibre Plan.

thanx for reply, im not fussy , just want tiles down and not to break under foot.

just need try figure out how to make cuts in backerboard, got quite a few cuts at radiator pipes, cistern water pipe and a 12" box cutout for boxed of pipes.

the room is 44" by 92" and at sink part is extra 27" by 22"

so prob need abt 4 boards?

is it best to use roofing nails to affix aswell as what adhesive?

FORGET NAILS ...Screws

ahh ok thanx, i read a diamond edge jigsaw blade should cut the board in the hard places, is this true?

i prefer screws, do they go in ok or should i countersink hole and drill small hole for them to go through board or will cordless screwdriver manage the job ok.

its just i read on the hardi instructions to use hardi nails or roofers nails.

do i need the special tape?

will the backerboard stay ridgid when screwed down or will it take the shape of the floor?