Stains on white limestone floor

[jonnyc]

dont worry about only sealing once .
One mans one sealing coat might be equal to anothers 3 coats.
Some people seal once or twice after fixing when stone dry before grouting.
if you are worried you have not sealed enough, just take a look at your photos .
these stain marks do not correlate to lack of sealing alone.
the staining or rather lack of would be uniform if you had not sealed enough.
This is a moisture issue and covering problem.
I dont really know what general advice to give because every case is individual .

 

[DHTiling]

I just asked as i thought you meant you had finished totally...

Was there moisture still in the stone before they covered it..? from the grouting..

Just trying to make sure no blame comes back to you..

 

[stone tiler]

Thanks. I have been worried about it to be honest. Tiles were all dry and fine when I left. Client and contractor have agreed its nothing to do with me so I'm pretty clear of the mess I hope.
I'm just trying to fix this for the client and earn brownie points.

 

[jonnyc]

This problem is typical for me as a regular stone fixer in the end of market that i work in ,that requires a temporary floor covering for perhaps 6 months before completion. Every job we do is different.
We are dealing with a natural product , but this product differs hugely .
Gone are the days when fired earth delivered terracotta/slate tiles that were dry and could be presealed on the floor of a garage or outside before fixing.
Few stones come dry by dint of fact that they are cut from block and crated instantly.
We should adapt to every stone as they show themselves to us .
I fear that there seems to be a generalisation developing that all stone is the same and can be treated as such.
But as all we stone members know, we need to treat each stone with respect as they have more quirks than we ahve to offer.

 

[jay]

This might ruffle a few feathers but, If the floor wasn't finished as in two coats applied for full protection then is there a chance that some of the problem is also the tilers fault 😳

 

[Topshop]

I don't think that any amount of sealer would have stopped this from happening when a barrier was holding moisture to the stone for months like that. The stone will not dry out fully for many more months with the sealer on it which is now holding the moisture in. You need a stone refinisher to open the stone back up. It is hard to say how deep the problem sank into the stone until it is opened up. It may be possible that just a brown cleaner pad on a swing machine will remove it because limestone is actually kind of dense.

 

[jay]

I don't think that any amount of sealer would have stopped this from happening when a barrier was holding moisture to the stone for months like that. The stone will not dry out fully for many more months with the sealer on it which is now holding the moisture in. You need a stone refinisher to open the stone back up. It is hard to say how deep the problem sank into the stone until it is opened up. It may be possible that just a brown cleaner pad on a swing machine will remove it because limestone is actually kind of dense.

Agree but if the person who covered it finds out it wasn't fully sealed (two coats) then it sort of leaves an opening for a way out

 

[jonnyc]

dont agree with this one coat/two coat/thee coat mularchay.
stone fixing is not a science .
every stone demands respect from the installer.
from my experience over the last 20 years , one should never assume that you can generalise about how to fix/grout and seal any particular limestone.

i dont think many can remember or even know how stone was sealed this long ago.

 

[jay]

dont agree with this one coat/two coat/thee coat mularchay.
stone fixing is not a science .
every stone demands respect from the installer.
from my experience over the last 20 years , one should never assume that you can generalise about how to fix/grout and seal any particular limestone.

i dont think many can remember or even know how stone was sealed this long ago.

Yes all stone is different and take different attention but most sealers these days require 2 coat's in GENERAL to achieve a proper seal

 

[Pebbs]

I had a look at the photos, and to my eyes the stone has sweated. Underfloor heating and corex on the surface are not a good combination, the moisture rises upwards and then has no where to go. What I would recommend here is that the floor is stripped with a kleever and then grinded back and then re-honed. With the queries raised about the amount of sealer on the stone, Jonnyc is correct some stones soak up the sealer so you can go up to 3 coats, others will only need 1, so bear that in mind its not a rule, sealers can also darken up stone, some clients dont want that colour change.

Also I want to re-iterate something regarding the drying out of stone, it can in some cases take up to 3/4 months to dry out. I have a project that we completed 6 months ago and the stone Pietra Serena is only now ready to be sealed, luckily for us its internal walls. If you seal to soon the water gets trapped on the surface between the stone and the sealer. Always be absolutely 100% that the stone is at least 90% dry before applying any sealer.

Pebbs