Ceramic Floor Tiles Have Dark Spots Over Heating Pipes

[gregdornan]

Please Help!!

I have recently laid white ceramic tiles throughout my kitchen/diner about 4 months ago. I have laid the tiles on plywood using a flexible adhesive. Underneath the plywood is a concrete floor, which was put down in the 1970's.

However the problem is:- I have recently turned the heating on due to winter coming closer & the strip of white tiles which are directly above the heating pipes in concrete connected to the radiator have turned a shade of dark, almost as if they look damp underneath.

I have checked my boiler & it appears that pressure seems ok which to me would indicate their is not a leak in the pipe.

Any thoughts?????!!

 

[wap]

how did you fasten the plwood down? if you screwed it you may have gone through the damp proof membrane. there wesnt a black covering on the floor was there?

 

[gregdornan]

I had to use loads of no more nails & i also nailed it down with 1 inch masonry nails to secure. I had to do this as the base is concrete that the plywood is sat on.

The concrete did have a layer of black tacky coating on top of the concrete but i think this was used to secure the old parquet flooring. From the outside wall, i can see a damp course has been installed much lower than the base my tiles lay on or the nails i used can penetrate.

I have been told by a person in the building trade yesterday that it sounds like the heat could be burning the tiles from underneath. Could this happen?

 

[gcol]

I have been told by a person in the building trade yesterday that it sounds like the heat could be burning the tiles from underneath. Could this happen?

Nope. Tiles are manufactured using very high temperatures so the relatively low temperatures involved with under floor heating will have zero effect on the tiles.
You're on the right track when you suspect moisture though. Have you tried leaving the heating on permanently for a few days to try and dry them out?

 

[gregdornan]

Thanks for the reply, since posting a few days ago it would appear the tiles are slowly losing the dark colour that it gained, so def moisture!!!

I had a theory that perhaps when the heating system was installed after the house was built, to lay the pipes in the floor they may have cut the damp proof course to lay. Just a thought!!

I thought of turning the radiator back on, allowing the pipes to heat up below the tiles again, only trouble is, im s&*^%&g myself that the tiles could get worse not better.

What do you reckon?

 

[gcol]

I thought of turning the radiator back on, allowing the pipes to heat up below the tiles again, only trouble is, im s&*^%&g myself that the tiles could get worse not better.
What do you reckon?

Have you tried leaving the heating on permanently for a few days to try and dry them out?