Grout cracks between tile and plastic trim

[JenAntalya]

Hi,
I am an American living on the Mediterranean coast, where we have long, hot, dry summers. Our apartment pool and terrace tile has always been grouted with flexible siliconized grout made for pools, with the brands available in Turkey. Our overflow drainage trench (which has been covered with liquid insulation and mesh the past 3 years, tile underneath), has recessed ridges at the top to support the plastic grating. There is L-shaped plastic trim installed on those ridges around the entire perimeter. Each year we do grout repairs before opening the pool, but there always seem to be increasing cracks in the grout line between the plastic trim and the hard border tile. One pool engineer here said that trim is useless; recommended that we remove it, seal the exposed surface with more liquid insulation, and just sit the grating directly on top of the ridge. Another pool engineer said the plastic is fine; just remove the old cement grout and fill it with epoxy grout instead. I have read and been told that epoxy grout has excellent durability between ceramic tiles. However, since the plastic is prone to flexibility, the hard epoxy could crack and separate at the edge. I am having trouble finding information about this precise problem here. I would appreciate any professional advice. Thank you!

 

[ajw22]

Your precise problem is the use and interfacing of dissimilar materials. Dissimilar materials expand and contract at different rates and have different flexibility.

Trim is precisely that—trim. It is used to make a rough edge look better, and it usually has no functional purpose.

Both engineers are correct.

Cracked grout is usually caused by surface movement, water erosion, or freeze/thaw cycles. Does your pool experience freezing temperatures in the winter?

I can see the L shaped plastic trim in your pictures. I cannot see areas of cracked grout. Please post some pictures with the problem areas highlighted.

 

[JenAntalya]

Thank you for your reply! If you zoom in on the second photo, you can see a fine crack where the plastic trim is separating from the mortar. You can move the trim away from the group with your fingers in these spots. The combining of dissimilar adjacent materials makes sense to me. Here in Antalya we never have freezing temperatures. Winters are short and Greg into the low 40s F sometimes, frequent rains but not all the time. Summer temps can get up to 115° F or more! Similar to parts of LA. Any reason why epoxy grout might work in this case?

 

[ajw22]

you can see a fine crack where the plastic trim is separating from the mortar.

Please circle it with a color.

You can move the trim away from the group with your fingers in these spots.

No grout will adhere to plastic. I would expect some water erosion will separate the grout and the plastic.

Any reason why epoxy grout might work in this case?

I don't think it will make a big difference.

 

[JenAntalya]

View attachment 637348
Thank you for your reply! If you zoom in on the second photo, you can see a fine crack where the plastic trim is separating from the mortar. You can move the trim away from the group with your fingers in these spots. The combining of dissimilar adjacent materials makes sense to me. Here in Antalya we never have freezing temperatures. Winters are short and Greg into the low 40s F sometimes, frequent rains but not all the time. Summer temps can get up to 115° F or more! Similar to parts of LA. Any reason why epoxy grout might work in this case?

Sorry, not mortar, grout

Please circle it with a color.



No grout will adhere to plastic. I would expect some water erosion will separate the grout and the plastic.



I don't think it will make a big difference.

Thanks!

 

[JenAntalya]

The arrow is pointing to the crack between the plastic and grout.

 

[ajw22]

View attachment 637352
The arrow is pointing to the crack between the plastic and grout.

You call it a crack. I call it a joint.

You will always have a joint between different materials.

What problem does it cause?

 

[TinFoilHat]

It certainly looks fine to me. I wouldn't be concerned about it.