Efflorescence or Sealant problem on Indian Sandstone

[adam72]

Hi all, I have recently had an Indian Sandstone installed in Oxfordshire, after some thought I decided to seal it, we have parties, we have kids and I have clumsy other half.

I waited for around two months to see if there was any obvious signs of Efflorescence, I then washed the patio down left to dry for a few days, swept clean and applied LTP Mattstone as recommended on these forums and a few others.

Everything was fine until we watered a couple of plants and a couple of white spots appeared but nothing to worry about, then the rain arrived last night and today and I have quite a lot of white patches come from nowhere is it Efflorescence? or a sealant problem? any advice and recommendations would be really welcome.

Thanks in advance.

 

[peterwhayward]

I think you have answered your own question........sealing problem, would be my guess if it appeared only after getting wet.

 

[adam72]

Cheers, I cant seem to post pictures no matter how much I resize the image I am over my limit.

I followed the instructions fully with the sealant, what can I do to remove the white patches?

I am starting to regret this sandstone patio.

 

[adam72]

I would insert images, however the site is not having it, I guess this is down to me been a new member?

 

[Andy Allen]

Was the stone fully dry before sealing..?

 

[adam72]

It was dry, it was only the other week during the hot spell, I applied to sealer during the early evening so the temp was lower and there was no direct sunlight.

 

[Ajax123]

What is underneath the tiles?

 

[adam72]

I believe it is mortar, I was away when the work was done, I have contacted LTP and sent them images, they believe it is Efflorescence from the pictures I sent, they were helpful and have sent out a grout cleaner...lets see if it works.

 

[Ajax123]

So they're on a layer of mortar and they're outside?.

 

[adam72]

yes sorry for the guessing game ,I thought I put down it was patio so yes outside.

 

[adam72]

I have applied the grout cleaner...it does look like any improvement so far.

 

[adam72]

Well its looking worse after applying the grout cleaner, more of a milky film over the slab rather than the white marks and spots.

 

[adam72]

Great I can add some images if anyone can advise that would be great



Before



After

 

[mike1979]

Try some xylene or thinners xylene is used on patteren imprinted concrete to take away white patches in situations where sealer has been applied to a slightly damp area or if it rained after sealing it might be moisture trust me give it a try xylene is what really is needed you can get it on the web but try some thinners brush it quite hard and use a healthy amount it melts and heats the sealer a bit give it a go

 

[adam72]

OK Mike cheers, do I apply this neat? do I just apply and let is soak in or wash it off after so many minutes? Cheers