Bathroom floor

[JohnBishop]

Hi All,

  I just ripped these old 5mm wooden boards that were under the vinyl.
Currently floor boards are exposed.
What would you recommend I should do next?

Should I get new 5mm OSB boards and put on top or plaster boards then attach them with some special screws?

So:
1. floorboards

2. plasterboard / OSB

3. thinset

4. Schluter DITRA decoupling membrane

5. thinset again

6. Schluter Kerdi membrane in the corners to waterproof

7. thinset and tiles

Have I missed anything?

Thanks

[nod]

Osb is no good Use ply or cement board Thin coat is no good for Ditra Ardex 200 is bombproof 

Better with a PB plank for sound deadening 

If you use a cement board or insulated tile board No need for Ditra Jus use a flexi adhesive The bed should be the same thickness of the tile your putting down 

Good to go 😁

[JohnBishop]

1 hour ago, nod said:

Osb is no good Use ply or cement board Thin coat is no good for Ditra Ardex 200 is bombproof 

Better with a PB plank for sound deadening 

If you use a cement board or insulated tile board No need for Ditra Jus use a flexi adhesive The bed should be the same thickness of the tile your putting down 

Good to go 😁

what is PB - a plaster board?

 

1. floorboards

2. cement board / plywood

3. Ardex 200

4. Schluter DITRA decoupling membrane

5. Ardex 200 (Schluter Kerdi membrane in the corners to waterproof)

7. Tiles

 

OR
If cement board should I just get this one?

NoMorePly 12mm Fibre Cement Construction Board 1200 x 800mm or a larger plasterboard so there is fewer gaps / joints?

 

So in this case just:
1. floorboards

2. screw in cement boards (I reckon I should waterproof the edges at this stage)

3. flexi adhesive with the thickness of the tile

4. tiles

[nod]

We often use vent board on uneven floors We bed them down with rapid set flexi adhesive Then put some screws in once set Only a dozen per board Gives a rock solid flat floor 

Paint both sides of the cement board with SBR 3-1 mix 

 

[JohnBishop]

16 minutes ago, nod said:

We often use vent board on uneven floors We bed them down with rapid set flexi adhesive Then put some screws in once set Only a dozen per board Gives a rock solid flat floor 

Paint both sides of the cement board with SBR 3-1 mix 

 

In my case the floor looks like that. I am going to nail the existing nails deeper and put some extra screws for better rigidity.

 

So I should use regular cement boards 1200mmX800mm paint them with SBR on both sides.

Should I in my case use rapid flexi adhesive between the floor boards and cement boards or just screw them in?

[nod]

The floor doesn’t look bad at all 

You could go directly onto that with Ditra 

Or simply bed a cement or a 10 mil insulated board down 

[JohnBishop]

5 hours ago, nod said:

The floor doesn’t look bad at all 

You could go directly onto that with Ditra 

Or simply bed a cement or a 10 mil insulated board down 

right, I would want to have some sound deadening (this is 1st floor) so I attach a cement board with flexi adhesive and some screws unless there is some extra layer I should put for that.

[JohnBishop]

7 hours ago, JohnBishop said:

right, I would want to have some sound deadening (this is 1st floor) so I attach a cement board with flexi adhesive and some screws unless there is some extra layer I should put for that.

a quick question. What about STS Tile Backer Board? I understand I should skip it

[JohnBishop]

Ok I decided to go for this 12mm STS Tile Backer Boards instead so:

 

1. floorboards

2. flexi adhesive

3. STS tile backer board + screws and washers

4. flexi adhesive

5. tiles

 

The last two question?
1. these boards are waterproof and the adhesive is also waterproof. Do I have to put anything in between the boards or the adhesive is enough?

2. finally what should I use to waterproof where the floor connects with the walls?

[PeterW]

2 hours ago, JohnBishop said:

Ok I decided to go for this 12mm STS Tile Backer Boards instead so:

 

1. floorboards

2. flexi adhesive

3. STS tile backer board + screws and washers

4. flexi adhesive

5. tiles

 

The last two question?
1. these boards are waterproof and the adhesive is also waterproof. Do I have to put anything in between the boards or the adhesive is enough?

2. finally what should I use to waterproof where the floor connects with the walls?

What’s going on the walls..?

 

And nothing needed between the board edges as the flex adhesive will sort that as you butt them together.

 

Don’t forget to start with your highest point first and also remember where your drains are going. 
 

Are you planning any sort of electric tile heating ..?

[JohnBishop]

7 hours ago, PeterW said:

What’s going on the walls..?

 

And nothing needed between the board edges as the flex adhesive will sort that as you butt them together.

 

Don’t forget to start with your highest point first and also remember where your drains are going. 
 

Are you planning any sort of electric tile heating ..?

yes, tiles also go on the walls, at least 3 walls.
Do you mean to tile top down on the walls first then the floor?

I wasn't planning to install any electric tile heating under the tiles. Should I? I mean it's not the coolest room in the house.

[PeterW]

Tiles can feel cold under foot and for the £40-50 for a kit it can make it nicer. 
 

On 06/05/2023 at 08:01, PeterW said:

Don’t forget to start with your highest point first and also remember where your drains are going. 

Get a level to the floor and see where the high spots are. Your floor needs

to be perfect or the wall tiles will show up the difference. You start with the thinnest smear of adhesive under the highest board and level as you go. 

[Nickfromwales]

Floors down first, every day of the week. Makes for a much nicer look to the cuts around the room, and also allows you to seal the floor tile to the wall around shower / bath / splash zones.

Plywood, glued and screwed onto that floor will be easy, cheap and simple to do ( with minimal additional build-up / height at the threshold ), and defo screw the floorboards down tight first, as if you start with a loose floor, that's what you'll finish with ;).

I've never, not once in 30 years, laid a cement board down when tiling a regular floor, like this one is. Way too overcomplicated AFAIC.

For sound deadening, the floorboards, plywood, adhesive and tiles will get you where you need to be. If you're super fussy, pull up the floorboards and fill the voids with acoustic wool. Then when you re-lay the floor you can mark off services etc and screw the FB's back down with extra gusto!

If going for an UTH mat / wire, defo use insulated tile backer boards ( Wedi / Marmox etc ) as the response time and wasted electricity would otherwise be a bit of a PITA ( but not the end of the world ). It's 1st floor at the end of the day, so the UTH would be strictly a comfort installation, but on a concrete GF room it would be almost obligatory these days. 

 

No need for Ditra unless you're going to lay directly onto the FB's, but then you wont be able to level with anything other than the tile adhesive as you're laying the tiles.

[JohnBishop]

Gents, appreciate your responses. Thank you

Yes so far I have screwed many boards and hammered all the existing nails. The floor seems solid I continue walking and looking for the last squeak.

I have the 12mm insulated boards from Wickes. Can this substitute plywood?

 

Makes sense. I identify the lowest points and mark them with a pencil.

[saveasteading]

On 05/05/2023 at 20:24, JohnBishop said:

STS Tile Backer Board?

I used that to bridge over old floor boards before tiling.

I stapled it down which is what i would do again.

Then tiled.

The problem I had was that the floor was bouncy, very old and probably under-designed joists, so the STS, being flexible, did not help in stiffening the floor.

I think it all settled down, but a few tiles came loose when i walked on the floor perhaps too soon. (Not my house, now sold, so no latest report available).

Of course normally people don't jump on a toilet floor.

 

If your floor is robust then yes I would say STS is fine, and easy to use. plus helps a little in insulation.

If bouncy then I would use a cement board which would probably kill the bounce.

[Nickfromwales]

On 07/05/2023 at 19:04, JohnBishop said:

Gents, appreciate your responses. Thank you

Yes so far I have screwed many boards and hammered all the existing nails. The floor seems solid I continue walking and looking for the last squeak.

I have the 12mm insulated boards from Wickes. Can this substitute plywood?

 

Makes sense. I identify the lowest points and mark them with a pencil.

Yes, it can substitute, if fully bedded into flexible tile adhesive and screwed at the edges etc, but I would still ply it. Nothing worse than fitting out the entire room to then slowly see cracks in grout and then tiles coming loose.

Major works to put that right retrospectively. 
 

[JohnBishop]

On 08/05/2023 at 19:24, Nickfromwales said:

Yes, it can substitute, if fully bedded into flexible tile adhesive and screwed at the edges etc, but I would still ply it. Nothing worse than fitting out the entire room to then slowly see cracks in grout and then tiles coming loose.

Major works to put that right retrospectively. 
 

Right so how thick ply do I need for that?
I agree redoing the tiles on the floor would be a complete mess perhaps you have to replace the floorboards in the process.

Does it mean I put plywood boards first, screw them to the floor boards then I use the adhesive to attach the STS boards or I just screws them all together or separate of each other and adhesive only goes under the tiles?

 

I have these STS 30mm Screws and Stainless Steel Washers

I was going to attach STS boards to the floor boards with the adhesive and then these screws/washers but with extra plywood boards this would perhaps be too thick.

 

I also have EVO-STIK 1L Flexibond Tile Adhesive Primer
I was going to paint it over the floor boards before applying the adhesive.

[Nickfromwales]

2 minutes ago, JohnBishop said:

Right so how thick ply do I need for that?
I agree redoing the tiles on the floor would be a complete mess perhaps you have to replace the floorboards in the process.

Does it mean I put plywood boards first, screw them to the floor boards then I use the adhesive to attach the STS boards or I just screws them all together or separate of each other and adhesive only goes under the tiles?

 

I have these STS 30mm Screws and Stainless Steel Washers

I was going to attach STS boards to the floor boards with the adhesive and then these screws/washers but with extra plywood boards this would perhaps be too thick.

 

I also have EVO-STIK 1L Flexibond Tile Adhesive Primer
I was going to paint it over the floor boards before applying the adhesive.

Are you fitting UTH? If not, just ply. 

[JohnBishop]

2 minutes ago, Nickfromwales said:

Are you fitting UTH? If not, just ply. 

I think I pass on the underfloor heating. Do you mean ply or STS only or both?

[Nickfromwales]

38 minutes ago, JohnBishop said:

I think I pass on the underfloor heating. Do you mean ply or STS only or both?

Easy tiger.

How level is the floor?

[JohnBishop]

On 10/05/2023 at 15:35, Nickfromwales said:

Easy tiger.

How level is the floor?

Do you mean how level are the floor boards to each other or level in general.
If you mean how level in general then there is a drop of about 8mm across over 2m from the outside wall.

Not every floor board is even to each other but I have screwed them so there is no movement or squeaking.

[JohnBishop]

I would put some ply down but 9mm ply, 12mm STS, 9mm tile and at least two layers of adhesive makes it well over 30mm. Considering laminate floor to the bathroom will be a 20mm step at least.

If I go for 60cmX60cm tiles this should be fine. I understand if I go for smaller tiles.

Edited May 13, 2023 by JohnBishop

[Temp]

Just tiled my bathroom and debated if I should do walls or floors first. In the end I did this...

 

I fixed a batten to the wall about 3/4s of a tile up from the floor around the room. Used laser level to set this.

Tiled the walls from the batten up to the ceiling.

Tiled the floor.

When set, removed batten and cut bottom row of tiles to fit on wall.

 

The batten wasn't exactly 3/4s of a tile up... Before I started I drew pencil marks and lines on the wall so I could be sure that things like the shower outlets and mixer wouldn't require holes to be drilled very close to the edge of a tile. Also to ensure I wouldn't need to cut very narrow strips of tile anywhere (eg at the ceiling). I also checked for the same issues horizontally. 

 

 

 

 

 

[JohnBishop]

I bought some 5mm ply wood boards. Would this work in combination with STS?
If so how can I join all together?

 

1. floorboards

2. ply + screws

3. flexi adhesive

4. STS tile backer board + screws and washers

5. flexi adhesive

6. tiles

 

I have this EVOSTICK primer. In this scenario should I paint it over the floorboards or the plywood.
I think it makes more sense to screw ply and STS together, right?

[JohnBishop]

I have secured the underlying floorboards and decided to put down and screw these 5mm plywood boards.

 

Now I have these items:
1. STS screws and washers

2. STS 10mm insulation boards

3. EVO-STIK 1L Flexibond Tile Adhesive Primer

Can anyone tell me what should I do next?

Should I paint the Evostik on both sides of the STS and glue the STS boards to ply then screw them in.

Then I think I am ready to start tiling.

 

 

 

Edited May 18, 2023 by JohnBishop