Hi, I recently had a patio laid with Indian Stone, the contractor who did the job sealed it afterwards but it has gone dusty white over most of the surface, some of the white is flaking off, can anyone tell me what has caused this, and what should I get him to do to rectify it. Any suggestions would be useful, many thanks.

Sounds like efflorescence to me. Not sure if Tile Giant stock any remover or you could try Aqua Mix EFF-ex.

Hello..welcome..

what did he seal it with..?

Originally Posted by Dave

Hello..welcome..

what did he seal it with..?

Afraid I don't know

It could be a number of things ..

Could do with knowing what the sealer is and have you any pics.?

sounds like he may have sealed moisture in rather than out

although if it's flaking off, it does sound more like efflorescence

Originally Posted by doug boardley

although if it's flaking off, it does sound more like efflorescence

could be acrylic sealer flaking... could be residue within sealer... who knows without seeing it..

Efflorescence doesn't happen that quickly..

How long after the job was finished did this happen.?

but if it's an exterior installation Dave with no dpm, the sandstone will soak up underlying moisture like a sponge and be prone to sulphate attack?

Hi, I have some pics, but I don't know how to post them.

Originally Posted by Dave

could be acrylic sealer flaking... could be residue within sealer... who knows without seeing it..

Efflorescence doesn't happen that quickly..

How long after the job was finished did this happen.?

Hi, it was within a couple of days.

i have got indian sandstone on my patio and it is prone to effloressence it wears off after a while

Have uploaded the photos to an Album called Philayls Album, but don't know how to access them

Originally Posted by Philayl

Have uploaded the photos to an Album called Philayls Album, but don't know how to access them

Does look like a sealer problem to me...

wasthe sandstone sealed prior to grouting?

Originally Posted by doug boardley

wasthe sandstone sealed prior to grouting?

No, done after

looks like the sealer has bloomed to me this sometimes happens if you seal moisture in the tile

Like i said.. for salts to come through sandstone it will take more than 2 days..

Same for sulphate attack Doug..


Looked at the pics and it looks like what has already been mentioned.. sealer has bloomed due to moisture..and could just peel off if topical sealer was used.

You need to call the builder back and ask what he used and how long did he wait for the stone to dry before sealing.

Thanks for the info, will do as you have suggested

Hi, did you sort the white patches? Ive had the same happen to me. Indian Stone patio layed and looked beautiful. Then the cement pointing was done with a dry mix brushed all over, then brick acid to remove any stains, then sealed. Hey presto lots of white patches all ove rthe stone and a grey-ish haze which has dulled all the colours which were fine before. Not sure whether its the stone soaking up the concrete below, the sry mix brushed on, the brick acid or the seal so.... im getting the stone sandblasted back to an original layer which has not been treated and leaving it to let any natural chemical reaction to the underneath cement happen and hopefully in time they will look good as new. Thats the idea anyway which seems better than ripping it all up!

Is yours black limestone..??

No its a red/yellow stone. The red is more affected by the white patche, the yellow less so but im thinking thats just because its lighter and harder to see the discolouration

PS. Dave i can upload pics later on to show the discolourations, any info/help is much appreciated and if youre doubtful the sandblasting will restore the stone to a level not affected by the chemical recation caused by any of the dry mix cement brushing or brick acid or seal trapping in any/all of these your advice would be greatly received. The sandblasting is planned for the next dry day, probaly Mon or Tue next week.