Screed or Backerboard?

[Harburt]

Hi all

I am looking to tile the floor of a small downstairs cloakroom (picture at the end). Total areas only around 1.3m squared. Currently there's a mix of ply and original floorboards. The surface is generally level, but there are some very slight higher discrepancies between the different bits of wood, and also some slight gaps around the edge.

My question is, do I need to bother screeding to get it absolutely perfect level, or can I get away with just laying 10mm Backerboard straight down?

Tiles are 6mm porcelain.

Thanks

 

[bobasd]

Making sure the ply is well screwed down then you wont need any backerboard.
Adhesive will pick up any height differences - comb the floor and butter the back of your tile.
I assume that like most nowadays you will be using large format tiles?

 

[dontbelieveawordofit]

that’s not clear is it and blatantly incorrect. you just told him to tile on existing floorboards and ply patchwork.
why are you intent on giving people bad information .
op. you will need to overboard that with a 9mm ply screwed over the whole thing , preferably in one piece . then tile over it. you shouldn’t tile on floorboard.

 

[Harburt]

Hi Benny

Thanks for the info. Would you say 9mm ply rather than Backerboard?

Thanks

 

[bobasd]

Ignore the troll. eg. Its "not clear" but whats not clear is "blatantly incorrect"? Thank God he cant read?

What i suggested will work in a small area with large tiles but sure, overlay with 9mm ply if you want to, and again do it well screwed down.
Make a paper template for cutting the ply - leave a 10mm expansion gap at the edges and at pipe stubs.
Your finished tile floor must attempt to be be level with the other side of the threshold FFL.
No need for backer board in a non-wet area.

 

[Harburt]

Ok great, thanks. We're using 6mm porcelain tiles. They are a bit fiddly (the bosses choice, not mine).

The ply will be useful to bring it up to the height of the other side of the threshold so it's a bit of a win win really.

I'm guessing softwood ply over hardwood? Or is it not too big an issue given it'll be a single piece in a fairly small area?

Cheers!

 

[bobasd]

Looking again at the pic, & how you've pieced the ply in - it would probably be best to use the backerboard, dont use ply.
Its often best to use a tile saw with porcelain.

 

[dontbelieveawordofit]

Hi Benny

Thanks for the info. Would you say 9mm ply rather than Backerboard?

Thanks

ply. ignore bob . everyone else does. he hates it when he gets stuff wrong.

 

[dontbelieveawordofit]

Ignore the troll. eg. Its "not clear" but whats not clear is "blatantly incorrect"? Thank God he cant read?

What i suggested will work in a small area with large tiles but sure, overlay with 9mm ply if you want to, and again do it well screwed down.
Make a paper template for cutting the ply - leave a 10mm expansion gap at the edges and at pipe stubs.
Your finished tile floor must attempt to be be level with the other side of the threshold FFL.
No need for backer board in a non-wet area.

paper template? serious? like blue peter?

 

[dontbelieveawordofit]

Looking again at the pic, & how you've pieced the ply in - it would probably be best to use the backerboard, dont use ply.
Its often best to use a tile saw with porcelain.

how many more chances do you need to get this right bob. keep changing your mind . you’ll get there in the end.

 

[bobasd]

I'm big enough to change my mind when, on second thoughts, i can advise the OP better - learn from it.

Rubbish deleted
Mod

OP, there's a couple of reasons i changed my mind for BB.

 

[JaimieH]

6mm porcelain is thinner than the norm for floor tiles. It's imperative that your prep is correct to avoid any failure. It's a small area and completely empty so what I would do is remove all your floor coverings back to the joists and ensure they are all sound with no movement. If you suspect there may be any movement then strengthen between the joists with noggins. Lay a new floor of 22mm P5 moisture resistant chipboard screwed down securely and then overboard with 6mm No More Ply or 6mm Hardibacker board. Prime using an acrylic primer and then tile away using a flexible adhesive rated C2-S1 or C2-S2 if you want extra flexibility and piece of mind. It's not regarded as good practice to tile over any wooden substrates anymore. Good luck.

 

[dontbelieveawordofit]

6mm porcelain is thinner than the norm for floor tiles. It's imperative that your prep is correct to avoid any failure. It's a small area and completely empty so what I would do is remove all your floor coverings back to the joists and ensure they are all sound with no movement. If you suspect there may be any movement then strengthen between the joists with noggins. Lay a new floor of 22mm P5 moisture resistant chipboard screwed down securely and then overboard with 6mm No More Ply or 6mm Hardibacker board. Prime using an acrylic primer and then tile away using a flexible adhesive rated C2-S1 or C2-S2 if you want extra flexibility and piece of mind. It's not regarded as good practice to tile over any wooden substrates anymore. Good luck.

are you suggesting he cuts back the floor boards that run under the walls for the sake of making sure the joists are solid.
this is a 1.3m room, sounds like using a sledgehammer to crack a nut.
why are flexible adhesives specifically manufactured , with the sole purpose of tiling wood/ ply floors if its not accepted as good practice.
excuse my ignorance as i’ve only ever used ply .

 

[JaimieH]

Yes, that's exactly what I'm suggesting. The latest British Standards for wall and floor tiling recommends that the use of sheets or boards that are subject to moisture or movement should be avoided. It also states that plywood or other wood based sheets or boards should not be directly tiled onto. Aside from this you can clearly see that there is a massive join in the two sheets of ply that make up the current floor. Even the slightest movement in these will likely cause cracking of the thin 6mm porcelain floor tiles once fixed. I'm not going to argue with you though, I'm just giving Harburt my opinion. If you want to carry on using ply it's none of my business.

 

[dontbelieveawordofit]

was hinting at more of an education than an argument.
thanks for the advice.