I laid approx 160 sq mts polished grey jura limestone 900x 600mm 7 months ago

screed laid four months before.
Ditra used.
Stone set in fast set adhesive.
Job took just over two weeks to lay
checked stone dry after 10-14 days by heating a stone with haidryer for 30 mins. No change in colour.
No condensation under plastic if left overnight.
Paper left overnight no damp.
So sealed with mn stainstop.
Grouted next day.
Washed floor next day .
Left stone further 2 days to let grout dry then last coat stainstop.
No problem so far.

Floor covered with building paper with tape on overlapping

joins but not stuck to floor as advised.

Some time later, 40% of floor had hardboard laid on top of paper and other 60% had cordex put on top of paper.
Paper had been removed round edges to skirt floor and now mixture of duct tape and masking atpe used to stick edges of covering to floor.

This was left like this for about 5 months i think and underfloor heating turned on.
When covers taken up recently the area covered by cordex and paper had many water type stains with a slight silver colour in it like salt, which must have been caused by sweating /condensation.
This stain seems to be right in stone not on top.
The stains look like following the paer that has rucked up/shrivelled when wet.
They are not cordex pinstripped lines.
Strangely there was no staining to stone where covered with building paper and hardboard.
Board must have sucked up condensation/sweating and surprsingly resin in board not gone in to stone as i feared would have happened.

Have tried to clean stone with wexa/power clean/stainaway/wax off and brickie(non acidic they said but it certainly is as took polish straight off stone)

none of these cleaners worked.

Builder has now uncovered floor again and turned on heating thinking that this will get rid of staining but i do not think this a moisture problem still in stone.
It is almost as if it is some kind of mould/salt reaction in stone from stone sitting on condensation for so long

has anyone had a similar problem and been able to rectify.
I think it needs some kind of mould salt cleaner that does not affect polished stone
stone fed has suggested a paultice over whole floor,but where to go for that .
Or perhaps regrinding floor but this may not work if deep in to stone.
There will also be the problem of glue residue from dukktape to remove .
What is best product that will not damage polished surface.

Any suggestions appreciated.

Was the floor heating commissioned before stone was fixed and any chance of some pics as that would help

No it wasnt , but had ditra mat down to allow for vapours.
The screed had been down well over 4 months before tiling done.
The problem is that area covered in plastic could not breath.
Other area which could breath is fine.
Will try and get pics.

Pics would be good... plastic will cause air moisture sweating.. and this could have cause efflorescence..

dave
good point .
been thinking about this already.
do you think that the air trapped under plastic and stone could cause condensation in itself when floor heated up even if stone/adhesive bed dry underneath.
I have also been told by stone fed that any moisture in screed below ditra mat could force its way up between ditra mat joins and disperse across floor as has happened.
are you au fait with dura grey.
does it have any special properties.
my understanding is that efflouresence is caused by natural organic matter in stone activated by moisture coming up through stone.

If you had any moisture then it can cause it with new screeds etc.. but also efflorescence will show it's self later on as the crystals grow.. even in the grout lines.. it is just an option to consider..

I've seen it show up following the Ditra joints but it "bloomed" outwards from the line getting fainter as it spread. The floor I looked at was similar in that the screed had been down for a good while and uncovered but the UFH NOT turned on. Tiles were fixed in late Winter/Early Spring and then covered for about 6 weeks for other work to be done. When uncovered (polythene and hardboard) the floor was stained. Jura Grey from (I think) Mandarin. Contractor was beside himself, tilers were scratching their heads and customer was in tears. I was tiling elsewhere on site and asked what I thought. Told them to check moisture levels of the floor especially where the staining was bad. They found that it was higher on the grid of staining so they thought it must be moisture coming up through the tiles.

Duuno how it works but in discussion with bods on site they felt that the covering had drawn the moisture up through the tiles causing discolouration to form on or near to the surface. I always thought that the salts were white but this staining had different colours. Their solution was to use SEI Limestone Restorer, turn the heating on (slowly up to ambient temperature) leave it for the weekend and re-seal. The other option was take up the affected tiles and replace them (about 80 tiles). I kept my distance and did my bit in the bathrooms. The floor looked ok when I was done but I haven't been back or seen anyone from the job since.

thanks very much for this.
i would like to talk to you if possible.how should i give youmy number.
sounds similar problem

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cant find sei limestone estorer anywhere.
this sounds like it would solve the problem.

here are some photos of stains.
i now know they only go down in to stone fraction of mm

Doesn't look the same as the staining I saw. This was more localised and kind of in straight lines and "feathering" out a few inches on either side. That looks like efflourescence to me.

The only SEI stuff I can find is on a website in the States. There is a contact section to see if they sell in the UK or under a different name. Having looked at the guff my only worry would be that its a polished finish. Out of interest have you spoken to the supplier to see if they have had any other problems. Bad batch? Had a one off bad batch of Jerusalem Fossil which efflouresced in a shower room. They paid up for a deep clean and re-seal including moisture testing.

Limestone Cleaner Soote Remover Cleaner Brick Block Cleaner Remover

I have left a message on the customers home phone (Monday) and am waiting a reply. It was a couple of years back so we'll see what comes up.

Daft question but some stone restoration people might be worth talking to.

the sealer you have used im not familiar with it is it a top sealer or an impregnator

no mate, it was a limestone cleaner I (think) I saw a builder use to clean polished limestone which had bloomed from under plastic sheeting. Think it a similar problem to Jonnyc's. Trying to find the stuff and the builder or client that used it (not my work I did ceramics in the bathrooms). Not having a lot of luck. check out teh full thread to see if you can shed any light for jonnyc.

So sealed with mn stainstop.

i would try in a small area to strip the sealer off and see what it is looks like moisture under sealer

yeah but the process jonny described meant the floor should be dry. Even with a cover on the stainstop should stop any downward penetration. Though that certainly looks like its come upover. Had a chat with a marble lover today and he said find someone to strip, polish and seal it. I wonder what it would have been like if it hadnt been covered. jc says he's done loads and not had a problem so why this one. Is it the stone itself? Too wet too long in storage or shipping?

remember the floor hadn't been commissioned before sealing any moisture in the slab would of been forced to the surface on commisoning. it doesn't take much moisture to do it
i could be wrong

Originally Posted by jay

remember the floor hadn't been commissioned before sealing any moisture in the slab would of been forced to the surface on commisoning. it doesn't take much moisture to do it
i could be wrong

so who's at fault? Is there a solution? Who pays? Glad its not me. Just priced up a new orangery floor and have added a paragraph about commissioning the UFH (now to be standard in my UFH stone floor quotes). It'll upset the kitchen people cos it will add time to the job but hey I dont want to have 55m of stained limestone on my plate.

the solution is to allow the slab to dry and follow the recomendations with underfloor heating , commissioning before fixing of tiles
in other words you cant rush the job
if you cut corners it might come back and bite you

as for whose at fault,,, because the area affected by being covered in plastic is damaged .might be the first port of call who decided to use plastic (as plastic laid on bare concrete will make it sweat or attract moisture) the reason i think it has effected the sealer is because the moisture has no were to go . the other area could breath and allow moisture to escape, but not were the plastic was used,

thanks for trying to get that tel no.

i treied calling the states contact tel no but all they have is some ridiculous system asking for your pin no ,whatever that is and tel no. so cannot get through to them.
have emailed but no reply.

regarding floor have now had a marble company do test where they use diamond pads and repolished.
the stain did go so it must only be the fraction of mm of stone.
just worried about matching the newly polished floor up to rest of area and stairs.
was hoping to find a miracle cleaner without taking polish off.

its not moisture from screed as that had dried for 5 months and had ditra on top.
restoration company are sure it is from moisture in air under plastic which was taped to floor so could not breathe at all.
this caused some condensation where siting on top of stone.
thanks for thoughts