Help!: Tiling on an uneven floor

[ripkord]

Hi all, hope you can help the newbie!

My girlfriend's flat has a lovely bathroom that is ruined by a load of broken floor tiles, by the looks of things the previous owner has stuck down right onto (what I can only presume is) uneven floorboards (if its the same as the rest of the flat!).

What I planned to do was:

Lift the existing tiles,
Screw down any floorboards that have any play in them (as much as I can)
Cut some plywood (does this need to be treated?) to shape - screw that down.
Tile - with spacers and adhesive
Grout


Does that sound about right?

Thanks for any help!

[david campbell]

your on the right tracks,use minimum 15mm wbp ply and a good flexible adhesive and grout!

screw ply at 200mm centres

[ripkord]

Nice, thanks for the help!

[Daz]

You're deffo on the right track.

1. Lift existing tiling and clean away any adhesive residues.
2. Screw down any loose floorboards.
3. If there is no deflection (bounce) then glue and screw 6mm cement boards. If there is still deflection, then screw down ply (18mm preferred). Prime underside and edges of ply, before fixing, with an acrylic primer.
4. Tile with a (bagged) flexible adhesive.
5. Grout with a flexible grout.

Good luck .

BTW, welcome to the forums

[whitebeam]

I would consider hardie backer 6mm

[hunters tiling]

if you have the time maybe consider lifting the floor boadrs aswell and fitting 18mm wbp ply onyo the joists this stops any movement from having floor boards and also keeps the floor hight to a minimum. pva bond it aswell.

[davy_G]

Hi RK,
You sound like your on the right track.
Screw down the floor boards with extra noggings and supports where required. Removing as much movement as possible.
Then plying for the DIYer is probably the best way to go. However Im not sure if you intend to remove the toilet and sink as you mention cutting to 'shape'. Remove them if you can prior to doing this work and tiling as it is much easier, stronger and looks much better than cuts.
The ply needs to be at least 12mm thick, preferably exterior grade and screwed at 200mm centres with screws that are not longer than the 12mm ply and the depth of the floorbloards.
If the 12mm ply is too deep you could use 6mm cement reinforced board ie hardybacker so there is not a 'step' into thebathroom.
Once that is all done, tile away using flexible addy, possibly 2 part, and flexi grout, at least a 3mm spacer. Speak to your tile supplier for more info on what adhesive they have. Dont go to any of the big DIY shops as they are not fully qualified in everything they sell, how can they be experts in so many things!

Any more questions fire away and im sure more folk will follow with more advice and tips.

Good luck

[ripkord]

thanks everyone thats really really helpful!

[doug boardley]

I'm with Hunters on this apart from using PVA and I'd probably use 25mm wbp plywood and a two part flexible powder adhesive
like the nane RipKord, used to do a bit of skydiving myself

[ripkord]

However Im not sure if you intend to remove the toilet and sink as you mention cutting to 'shape'. Remove them if you can prior to doing this work and tiling as it is much easier, stronger and looks much better than cuts.

This sounds ok for the toilet, but I'm not sure I can do this for the sink, the pedestal is already fairly flush with the bottom of the sink. Once I have removed the tiles and had assessed the situation I'll know more!

Adding 15mm to the height of the floor seems a lot, maybe the hardibacker stuff would be better - again will have a better idea once I actually see whats going on under there!!

Thanks

like the nane RipKord, used to do a bit of skydiving myself

Heh, wish thats why I picked that name, its from a radiohead song!

[Dave]

if you have the time maybe consider lifting the floor boadrs aswell and fitting 18mm wbp ply onyo the joists this stops any movement from having floor boards and also keeps the floor hight to a minimum. pva bond it aswell.

Are you sure..?

[tfs]

be carefull when screwing through the floor boards (there may be water/ gas pipes under the floor). Also, you may not have something to screw into beneath every tile. If this is the case then consider removing a few tiles to allow you to get a fix into the joists.

An even better idea might be to lift all the tiles, sheet over the floor and fix new tiles in accordance with the adhesive and grout instructions. At the end of the day if these tiles are breaking up now, there is a very good chance that the rest of the tiles will start to break also.

[hillhead]

you need to be certain of the floorboard depth before screwing the hardiebacker or ply down! i was accused once of punturing a water pipe but i know my screws and timber well and had deliberatly used 25mm,which were 2mm short of going through the ply and floorboard.

[Colour Republic]

Ripkord, It might be an idea for you to post some pictures on here after you have taken up the old tiles, just in case some of the members here spot a problem that might need sorting before you start tiling. You want to stay in the girlfriends good books right?

Good luck

[ripkord]

Haha, yeah will post some pics. Hopefully I'll be getting started week after next

[ripkord]

lifted a couple of tiles to see what im up agaist - looks like mdf or something under there - has been warped through dampness getting through cracks in the tiles... will putting hardi backer down on top of this be ok?

thanks

[tfs]

No mate!

You will need to lift the floor to eliminate any risk of this happening to the rest of the floor. At the end of the day its your choice but I would lift and fix nex tiles over a suitable sub floor

[ripkord]

Unfortunately I cant lift the existing floor without ripping out the bath too - this is a job to make the flat market ready and not really a long term solution, having said that I want to do a good job!!

[tfs]

I imagine some people would just replace any damaged tiles if they were planning to sell the property!

[ripkord]

haha, I'm not that shoddy

[Daz]

The correct advice would be to rip the existing floor up and replace with either 18mm or 22mm ply. In your situation, can you not just replace the damaged floorboards and then re-tile?

[ripkord]

not really, the entire bathroom floor is 2 large pieces of MDF / something like that - the seam between the two parts is where all the broken tiles are so there must be some kinds of depression at the seam. The way the bathroom is tiled and the way the bath is tiled in - if I was replacing the floor I'd be giving myself far more work than I had set out to do!

Would it be worthwhile putting down a thin strip of ply over the seam before putting the hardibacker down?

[ripkord]

I have attached a quick mock up in mspaint to try and demonstrate what I'm talking about. The large terracotta coloured bits are the floor. the squares are the tiles, obviously (not to scale :P) the large rectangle on the left is the bath.

The tiles are crached right along the seam between the two boards, cant see if theres any real dip or recession. Would an uncovered seam cause cracks?

Thanks.

[jay]

hi as advised above rip it out back to joists and start again water has got into mdf and swelled it its completly stuffed now if you try youl be wasting your money

[GirlRacerRed]

hi ripkord

thanks for the drawing there. that certainly helps to explain the situation more.

if the join between 2 boards is where you say, and there is no additional overboarding on the floor before the tiles were laid, I think it's pretty conclusive that the tiles, adhesive and grout failed because there was too much flex/movement in the boards under the tiles.

You need to take all the tiles up and start again in my opinion. a 6mm hardibacker board that covers both floor boards and straddles the seam would be more helpful to you. securing the hardibacker at 300mm centres or less will give the floor more rigidity and will stop the tiles cracking under the movement.

I don't see how the ply will give you any further rigidity.. The hardibacker will give the right amount of rigidity to the floor without adding an additional layer to it.

If the original floor boards are warped though, I would suggest you sort them out first if the warping causes a bump in the floor. Perhaps it might need additional screws to the joists?

I've just gutted my bathroom and have chipboard sheets down as my floorboards, and now that the original flooring (lino and laminate) has been removed and air has been allowed the flow, the damp areas of chipboard have now dried out.

best of luck and let us know how you get on. a good saying I came across on here is "Do it right, do it once"

GRR

[ripkord]

Thanks, there doesnt seem to be a recession at the seam to be honest, but there must be given that all the tiles right along the seam are broken. I had mentioned the boards look warped - they dont really, was just the angle I was at - the floor looks level from what I can see - need to get myself a spirit level and make sure. The floor looks in good shape apart from the seam - where there is a 5mm gap between the sheets!! :

[GirlRacerRed]

Thanks, there doesnt seem to be a recession at the seam to be honest, but there must be given that all the tiles right along the seam are broken.

looking at your diagram ripkord, there probably wouldn't need to be any kind of dip in the boards as such. if that's where people step out of the bath, a person just has to step in and out of there a few times for there to be enough pressure along the seam to cause failure.

the floor boards that are down either need replacing (if beyond repair) or re-inforcing. boards do bend when they're stood on, they will not be completely solid.

where abouts are you located ripkord? Maybe one of the guys from here could come round and help you to figure out a plan of action?

[ripkord]

I'm in Glasgow. I cant really justify taking out and replacing the floor - that would be a proverbial can of worms! If it was for the absolutel long term - I would definitely consider doing that!

[GirlRacerRed]

brian c is one of our Trusted advisors on here, and he is in Glasgow too

you can send him a private message http://www.tilersforums.co.uk/privat...o=newpm&u=1494

[ripkord]

do I need to use adhesive to stick the hardibacker as well as screwing it down?

thanks