Found myself back at the tiling! - TilersForums.com

[Perry]

This is why I stick to tiling and not orthopedic surgery.

 

[Time's Ran Out]

The substrata is 18 mm marine ply well secured to partition wall by screwnails at regular intervals coated with Bal sealer and two coats of "tanking" / WP1.

There are issues with the movement of wood no matter how well fixed - even 18mm plywood.
Then you've got a paint on tanking layer which is required to hold the weight of 1200x600x10mm tiles!
Ring BAL technical and see if they would guarantee this installation.

 

[Perry]

Gavin did you sbr the back and edges of the ply?

 

[Flintstone]

Overboard all the ply with 6mm wedi board of equivalent, and seal / tape all joints.

 

[LM]

The substrata is 18 mm marine ply well secured to partition wall by screwnails at regular intervals coated with Bal sealer and two coats of "tanking" / WP1.

Hi Gavin, it’s bad enough that the substrate is ply but to have it secured with screw nails instead of screws is a big risk also.

 

[Gavin Robinson]

Hi Gavin, it’s bad enough that the substrate is ply but to have it secured with screw nails instead of screws is a big risk also.

Locally we used / use the word "screwnails" for screws before there were such things as "threaded nails". The ply is attached with screws. Thinking that maybe this is a job - removing ply and or installing wedi board - that someone else can do.

 

[Gavin Robinson]

Gavin did you sbr the back and edges of the ply?

The ply was installed by the builders. I removed one sheet to reroute an electrical cable to reach a lighted mirror and yes both sides and edges are primed. The Bal tanking kit packaging is still in the bathroom.

 

[Gavin Robinson]

Overboard all the ply with 6mm wedi board of equivalent, and seal / tape all joints.

This would save removing the ply. Thanks

 

[Gavin Robinson]

This is why I stick to tiling and not orthopedic surgery.

I stick to things I feel competent at which usually but not always involves wood as the material.I am not a tiler but know how to tile competently in the normal tile range of sizes but the large format of the tiles in this job is the reason for seeking advice. I think you are suggesting I stick with joinery/ carpentery in this case.

 

[Gavin Robinson]

There are issues with the movement of wood no matter how well fixed - even 18mm plywood.
Then you've got a paint on tanking layer which is required to hold the weight of 1200x600x10mm tiles!
Ring BAL technical and see if they would guarantee this installation.

This is a Bal overview statement about one of their products -:

BAL Rapid-Flex Fibre Plus is a non-slip cementitious tile adhesive for walls and floors formulated with BAL Fibre Strand Technology (FST) for improved flexibility, strength and grab. Fast-setting in three hours, it provides extended open time of 30 minutes and pot life of 60 minutes, and is formulated for easier mixing and application. A high polymer content allows for tiling direct onto plywood walls, while it is recommended for large format tiles, areas of total immersion, limited movement and heated screeds.

Their tech spec indicates
Use for

•  Fixing ceramics, porcelain and vitrified tiles, mosaics, most natural stone, terrazzo, rigid foam insulating materials and brick slips in dry or wet interior and exterior environments.
  
  
•  Recommended for large format wall tiles, areas of total immersion in water e.g. swimming pools and showers.
  
  
•  Installations subject to limited movement and vibration.
  
  
•  Heated screeds.
  
  
•  Recommended for plywood walls.