Hello, I am looking for a solution to a tiling problem.
I want to install new tiles (slate) myself in my 30-year-old house.
The tiles measure 40 x 60 cm (16 x 24 inches) and are to be laid on the floor in a third-bond pattern.
In the old tiles, there are three movement joints in the middle of the room.
The room has a U-shape. The old tiles will be removed down to the screed.
The room has underfloor heating.
Two of the joints run perpendicular to the tile pattern.
Problem: movement joints running straight across the third-bond tile pattern.
My idea is to bond a thin waterproofing membrane with silicone over the movement joints directly onto the screed.
I would grind (mill) the screed slightly in the 1–2 mm (0.04–0.08 inch) area where the movement joint will be covered to avoid any raised areas.
After laying the tiles on the waterproofing membrane using C2FT S1 tile adhesive, I would cut through the membrane again along the tile joints near the movement joint.
My hope is that this approach will transfer the straight movement joint to the zigzag (third-bond) movement joint of the tiles.
The tiles spanning the movement joint in the screed would then “float” on a thin silicone bedding.
What are the possible disadvantages of this method, apart from the shear forces in the movement joint that might not be properly absorbed in the tile joint?
Are there any other alternatives to covering the entire floor with expensive uncoupling mats?
I appreciate any constructive feedback.
I want to install new tiles (slate) myself in my 30-year-old house.
The tiles measure 40 x 60 cm (16 x 24 inches) and are to be laid on the floor in a third-bond pattern.
In the old tiles, there are three movement joints in the middle of the room.
The room has a U-shape. The old tiles will be removed down to the screed.
The room has underfloor heating.
Two of the joints run perpendicular to the tile pattern.
Problem: movement joints running straight across the third-bond tile pattern.
My idea is to bond a thin waterproofing membrane with silicone over the movement joints directly onto the screed.
I would grind (mill) the screed slightly in the 1–2 mm (0.04–0.08 inch) area where the movement joint will be covered to avoid any raised areas.
After laying the tiles on the waterproofing membrane using C2FT S1 tile adhesive, I would cut through the membrane again along the tile joints near the movement joint.
My hope is that this approach will transfer the straight movement joint to the zigzag (third-bond) movement joint of the tiles.
The tiles spanning the movement joint in the screed would then “float” on a thin silicone bedding.
What are the possible disadvantages of this method, apart from the shear forces in the movement joint that might not be properly absorbed in the tile joint?
Are there any other alternatives to covering the entire floor with expensive uncoupling mats?
I appreciate any constructive feedback.
@ Dogger:
I do not want to join the discussion about which installation method and direction, or which visual effect, is considered positive or negative.
But regarding your comment "Problem: straight expansion joint perpendicular to the tile running bond pattern."
The drawing you posted elsewhere is quite informative!
I assume the blue line represents a fixed wall, while the red lines indicate joints considered problematic.
Here is my input:
If the blue line is indeed a partition wall, then (since this is a heated screed) an expansion joint as well as an area delimitation joint (in the ceramic covering) must be installed continuing along that line.
Very likely, there will also be a movement joint in the screed underneath that serves an important function and must be maintained.
You should immediately discard any ideas of using silicone or similar materials here, as that is neither proper nor technically correct.
All other joints marked in red are most likely “scare joints” only in the ceramic top layer.
These will also not be necessary in the future!
This means: only one expansion joint is required, which must be reflected both in the screed and directly above in the surface covering. It must never be filled or sealed!
Good luck:
KlaRa
I do not want to join the discussion about which installation method and direction, or which visual effect, is considered positive or negative.
But regarding your comment "Problem: straight expansion joint perpendicular to the tile running bond pattern."
The drawing you posted elsewhere is quite informative!
I assume the blue line represents a fixed wall, while the red lines indicate joints considered problematic.
Here is my input:
If the blue line is indeed a partition wall, then (since this is a heated screed) an expansion joint as well as an area delimitation joint (in the ceramic covering) must be installed continuing along that line.
Very likely, there will also be a movement joint in the screed underneath that serves an important function and must be maintained.
You should immediately discard any ideas of using silicone or similar materials here, as that is neither proper nor technically correct.
All other joints marked in red are most likely “scare joints” only in the ceramic top layer.
These will also not be necessary in the future!
This means: only one expansion joint is required, which must be reflected both in the screed and directly above in the surface covering. It must never be filled or sealed!
Good luck:
KlaRa
Similar topics