Concerned about void behind edges shower tiles.

[Mickey21]

Hi. Having shower tiled - porcelain tiles on waterproof insulation board. Wall is not straight so tiler is using adhesive to level the tiles. However there are some big voids behind the edges of the tiles (see image) where there is no adhesive - these voids are at the 2-3cm edge of the tile? Will this be a problem as I understand a high % adhesive coverage is required for wet areas? Note: on waterproof insulation board. Thank you.

 

[Dave]

Totally wrong fixing method

 

[Mickey21]

Totally wrong fixing method

Thx Dave - it did not look correct to me based on other posts hence the question. What would be the consequences of leaving this in shower area? Any views? Would it definitely lead to failure as there still seems to be a large area of coverage other than the edges? Thank you.

 

[Dave]

Thx Dave - it did not look correct to me based on other posts hence the question. What would be the consequences of leaving this in shower area? Any views? Would it definitely lead to failure as there still seems to be a large area of coverage other than the edges? Thank you.

Morning, at least the substrate is waterproof and they look like lightweight tiles , so might be ok if there’s 70% + coverage

 

[Bathfix Bob]

The grout will crack though....

 

[Mickey21]

Morning, at least the substrate is waterproof and they look like lightweight tiles , so might be ok if there’s 70% + coverage

Thx Dave. Tiles are 17kg/m2 and 600x300x8mm. Coverage seems to be +80% based on quick calculation. This technique is not dot and dab - think tiler is applying adhesive to back of tile but skipping edges to have space for adhesive to expand when pushing tile into place and adjust to create a flat surface. Will ask.

Based on gut feeling, not so much concerned about tiles falling off, but more about higher likelihood grout cracking, long term effect of water behind tiles, and lack of support when putting shower fittings on wall.

Walls fully waterproof with insulation boards sitting on top of tray, waterproof flexible adhesive in between boards and tray, and all seams covered with Mapei waterproof kit/tape. Also Aquastrap seal around tray that boards fit up against. Planning to seal shower tiles and grout lines as well.

 

[Mickey21]

The grout will crack though....

Thx Bob - yup this had crossed my mind. Cannot think of a mitigation other than sealing which I was planning to do anyways? Thx.

 

[hona7287]

You might mix some quite liquid adhesive and put them into a plastic bag; cut a small hole then fill the adhesive into the void.

 

[Mickey21]

You might mix some quite liquid adhesive and put them into a plastic bag; cut a small hole then fill the adhesive into the void.

Hi Arlo - thanks for the suggestion.

I was also thinking along lines of a waterproof expanding foam just into grout lines - need to be careful not to push tiles off wall. Or epoxy grout - but probably too complicated for tiler.

 

[Dave]

If there’s no movement in the walls . The adhesive is 80% + , so nigh on solid bed. The only issue is the voids on the edges where the grout will be. Unless you fully pack with grout it might as bob says crack with shrinking .