Ceramic tiles

[whiskywill]

I was recently asked if I knew anything about laying ceramic floor tiles on top of Weyroc boards. I don't so can anybody help? Can it be done?. Should it be done? Is there anything that needs to be done to the Weyroc before laying the tiles?

 

[blackrodd]

You will need to lay the tiles on a good quality ply, screwed every 8 inches centres every which way, as any chipboard is not good enough to take the adhesive, even trying unibond will leave problems, use 28, or 30mm screws so's not to pierce any pipework or cables.
Lay the new top sheets opposite to the previous floor ensuring staggered joints at all times.
I believe 12mm ply is a minimum, so that will mean ceramic tiles and a bed will bring the finished floor up another 10, or 12mm, Making 25mm in total, So either replace the existing floor with 20mm T&G flooring ply, or overboard the existing floor and cut the door bottom's before re hanging.
Tapered or beveled thresholds will be needed for stopping or starting the newer floors at openings.
HTH Regards Rodders

 

[stuartpaul]

I'm lead to believe that a lot of tiling professionals won't use plywood anymore and instead use cement board. Cheapest I found was 'no more ply' at about £4:50 a sheet if I recall.

I used this on my new kitchen floor (15 mm chip). I was told that if I'd used 22 mm I wouldn't have needed the board. The object of course is to remove flexing and together with the right adhesive my floor is rock solid.

You will get conflicting opinions on what to use and the final decision is up to you of course!

 

[Phil Pascoe]

I was advised by a professional tiler (and owner of a very, very good tile shop) to use at least 12mm ply and an adhesive designed to be used on wood.
Over an existing floor, of course.

 

[Graham Orm]

After making sure all the floor boards were flat and well fixed down, I always used 6mm ply fixed at 125mm intervals. This keeps the raise in levels to a minimum. Never had a problem in 35 years. I always used latex primer (NOT watered down PVA) Then a flooring adhesive suitable for wooden floors. Buy the stuff you mix up yourself, the ready mixed is bobbins.
Like any tiling, the finish will only be as flat as whatever you're tiling onto.

 

[RobinBHM]

I think tilers would want to use ditra mat over a timber sheet substrate.

 

[blackrodd]

Isn't 15 mm T&G chipboard flooring a bit on the thin side?
18mm and 22 mm are the recommended chipboard thickness, depending on the joist span.
Ply overboarding is proven to be successful in the main and does stop the flex that is the main problem with a chipboard floor, also any previous spillage of substances that would inhibit the sealer and adhesive working.
I can't see 6mm cement board making for a less flexible floor thal 12mm ply.
Regards Rodders

 

[AndyT]

Slightly off topic, but our Victorian house, like many others, has a couple of square yards of small quarry tiles just inside the front door. They finish level with the floorboards in the rest of the hall.
They are on a suspended floor, with a basement below. Does anyone know what the Victorians would have used under the tiles? I don't want to demolish it to find out!

 

[Woody2Shoes]

Slightly off topic, but our Victorian house, like many others, has a couple of square yards of small quarry tiles just inside the front door. They finish level with the floorboards in the rest of the hall.
They are on a suspended floor, with a basement below. Does anyone know what the Victorians would have used under the tiles? I don't want to demolish it to find out!

In my late Edwardian house they used a small amount of tar (just like under a wooden parquet floor) over the floorboards with strong cementitious grout between the tiles - sounds dodgy, but the boards were in excellent condition in a position fairly exposed to the weather (I suspect that the grout may have been maintained since it was new).

 

[Racers]

I remember drilling through a concrete floor that had been laid on joists covered with straw.

Pete

 

[stuartpaul]

Isn't 15 mm T&G chipboard flooring a bit on the thin side?
18mm and 22 mm are the recommended chipboard thickness, depending on the joist span.
Ply overboarding is proven to be successful in the main and does stop the flex that is the main problem with a chipboard floor, also any previous spillage of substances that would inhibit the sealer and adhesive working.
I can't see 6mm cement board making for a less flexible floor thal 12mm ply.
Regards Rodders

Oops, - it was of course 18mm chip not 15

Cement board may not be less flexible than ply but it helps to reduce any increase in floor level. During my research I was interested to hear a number of professional tilers stating quite categorically that they wouldn't use ply any more. This in spite of the fact that it's been used for years quite successfully.

 

[whiskywill]

Thanks for all the many and varied opinions. I will pass on to my friend who is due to start tiling his daughter's floor this weekend. I am sure he will now have something to think about.

 

[Phil Pascoe]

Slightly off topic, but our Victorian house, like many others, has a couple of square yards of small quarry tiles just inside the front door. They finish level with the floorboards in the rest of the hall.
They are on a suspended floor, with a basement below. Does anyone know what the Victorians would have used under the tiles? I don't want to demolish it to find out!

Mine were on bitumen with a cement grout - I took mine up eventually as the floor under them was breaking up. It was built in 1899. It was built on a slope with a basement and actually had a bitumen DPC.

 

[blackrodd]

Isn't 15 mm T&G chipboard flooring a bit on the thin side?
18mm and 22 mm are the recommended chipboard thickness, depending on the joist span.
Ply overboarding is proven to be successful in the main and does stop the flex that is the main problem with a chipboard floor, also any previous spillage of substances that would inhibit the sealer and adhesive working.
I can't see 6mm cement board making for a less flexible floor thal 12mm ply.
Regards Rodders

Oops, - it was of course 18mm chip not 15

Cement board may not be less flexible than ply but it helps to reduce any increase in floor level. During my research I was interested to hear a number of professional tilers stating quite categorically that they wouldn't use ply any more. This in spite of the fact that it's been used for years quite successfully.

In a nutshell, A chipboard floor's flexing is the big problem leading to cracks in the grout and then blown tiles.
Many people still use 18mm chip when 22mm should be used because of the joist span, so for a good job, if you lay down 12mm ply both you and the customer will not be faced with a grout or tile failure.
As I believe ply is stronger than cement board for flexing, I stay with the ply.
Rodders

 

[lurker]

Slightly off topic, but our Victorian house, like many others, has a couple of square yards of small quarry tiles just inside the front door. They finish level with the floorboards in the rest of the hall.
They are on a suspended floor, with a basement below. Does anyone know what the Victorians would have used under the tiles? I don't want to demolish it to find out!

Mine were on bitumen with a cement grout - I took mine up eventually as the floor under them was breaking up. It was built in 1899. It was built on a slope with a basement and actually had a bitumen DPC.

I have done exactly the same last summer.
I was told the tar was very cheap back then as it was a waste from the old town gas works.