Can someone help?

My tiler has laid 25m2 of 600x600 x15mm Basalt tiles using a BAL flexible adhesive on to sand and cement screed. The problem is marks have come up through the tile leaving dark areas on each tile. We have left this for 4 days but the marks are still very noticeable.

Can anyone help to why this happens and if it is possible to remedy so we can move on and seal.

Thanks

Hello and welcome.. when you say marks.. are they like roundish wet marks..?

pics would help oh and

Hi and welcome

Thanks for getting back so quickly!

I think the patches are dispersing and slowly fading 5th day now, attached picture showing the problem.

My suspicion is that the moisture has brought salts up through the tile.
Last night I covered one tile with a puddle of water and left this for a few hours, sponged it up then dried with a hair drier on cool! The patches came back but looking this morning have almost gone with a faint shape of the patch.

Is this normal?

your tiler has fixed these tile with mormal set flexi which has bleed through the tile!! these stone tiles should have been fixed with a rapid set stone ahesive and you would not have had this problem. the ahesive used can only dry now through the tile as it is trapped. this may take some tile just leave it and open windows / doors have a look in a few days time . it could take a few weeks .

what method did your tiler use to fix them?

Welcome

It should be a solid bed fix so cant see why its in small dots unless......... its dot and dab fixed Dot and dab fixing is not a suitable method of fixing tiles.

What grout spacing is that? Looks a bit small for a floor

Morning jimmy skins.

That is the reason i asked if they were roundish wet marks.. The Tiler has used a spot method of fixing and no back skimming of the tiles either which has caused this shadowing effect of the adhesive spots showing through.. it will dry out but isn't the correct method of fixing those tiles are any to say that.

The Basalt should also have been sealed.. you say you wet the tiles for a period of time and this highlighted the spot markings again, this makes me believe that the stone isn't sealed or insufficient sealer is in place.

"Normal set / Rapid set" He used BAL single part Flexible normal set due to the hot weather but the last day he used Mapei rapid set, to be fair they still have the same marks.

"Dot and Dab" Was not happy that this method was used, he assures me it will be ok.
He has put about 20 loads on each!

"...you say you wet the tiles for a period of time and this highlighted the spot markings again..."

I wet the tile last night and left the water on the surface for about an hour or 2. This has removed most of it
No sealer has been used yet he will eventually use Litho Fin I have seen this recommended by basalt stone sellers.

You just need to wait till they are dry/clean then you can seal..

Standard practise is a 100% bed is required... Also at the edges of the stone there will be little adhesive bed , thus giving no support to the grout, the grout will just want to drop into the voids.

So it just needs to dry and then he can seal..and fingers crossed it all stays intact.

He is not a tiler, dot and dab?

dot&dab shocking

I am not very optimistic that all the marks will totally disappear, this stone seems to easily mark (thinking why did I choose it!)
Can the adhesive colour come through the tile?

What are my options if the worst case happens and the marks don't dry out?

You can remove those tiles and fix correctly..but i am sure they will dry.. basalt is a dark stone and it should just be moisture from the slow setting adhesive..once sealed it will easier to clean etc.

The problem here is just fixer error and product knowledge.

Thanks

I seen this all before,a builder who i'm now his only tiling contractor had me tiling in his own house a few years ago. His front hallway was already tiled in travertine but it had started breaking in places,after my simple investigation it turns out some clown had tiled by dot and dabbing too.He had over an inch below some tiles
Costly repair.

dot and dab is lazy.There is no excuse,especially if the client doesent mind buying the extra adhesive.

Don't panic Jimmy - like Dave says they will dry out mate