Advice required,

A year ago I had an external wall tiled in natural stone slate tiles. Adhesive spots are now appearing on the surfaces.
I have tried cleaning with a cement acid which seems to have done the trick though I don't know if this is a permanent solution!
Does anyone have any Suggestion?
Sorry about the lack of further detail as I don't know which particular adhesive the tilers used.

any pics please would help, sounds like a dot and dab fixing method has been used

How big are the spots? a pic would be good. Is the stone definitly slate? And if so what type is it?
The more info the better for the guys to help.
And welcome to the forum

sounds like it was dot and dabbed spot fixed it may solve it long term but i think it will come back in time but not knowing how it was fixed and with what its hard to tell: Pete

... as per other members with regard to fixing. I'd contact the original 'tilers' and get them to provide a materials breakdown so further advice can be provided. Photos always help!

sorry i did,nt welcome you.

Hi and welcome, as you have found out lots of good advice here.

Hi and welcome..

Hi.... Was it a build up of salts showing the same size as the dabs or was it shadowing..?

Grey adhesive and light stone?? Perhaps

The tiles are definitely slate and the stains are of a light colour that probably are the salt from the adhesive.
Thanks in advance

Hi all,

the tiles are slate approx 8mm thick and of a light grey colour.
The stains are of an almost white colour and are exactly the same size as the adhesive spot/dab that was used to fix them to the wall.
i am trying to get the spec of the adhesive along with the pics requested.

Thanks inadvance for all inputs.

As requested here is a picture of the adhesive spots showing through.
The tiles are about 8mm thick and are grey slate. Chineses import I believe.
The adhesive is a grey powder type mixed with just water. thats all I can find out about it.
the spots do seem to be of a salt type stain but you cannot remove them with water only, you definitely need the acid.
In the pic you can see the area that i have cleaned.
Any suggestions appreciated!



andy_slate_001[1].jpg

looks like a dot and dab job ;(

Oh dear!

They've been spot-fixed, or dot and dabbed. Blobs of adhesive on the back of the tile instead of trowling (and spreading) the adhesive so the tile becomes 100% covered!

I think if the 'acid' appears to be working it's only soaking in the tile a little and working the surface.

Tiles shouldn't be fixed like that as they aren't fixed well at all. Worse on floors mind as the tiles break where there is no adhesive.

Really, they need to come off and be re-fixed properly.