Help!: white marks on my newly sealed black limestone

[lucysummers]

Just had 45m2 of black strata limestone laid, we cleaned it last week and allowed it to dry and then sealed it the next day with Thompsons clear limestone sealer, it dried for about 6 hours and then came the rain. I have now a patio covered with what looks like white salt marks and it looks horrendous. I called back the guy who laid it, who brought round some patio cleaner that contained acid, we tested a couple of the slabs, seemed ok so proceeded to do the top end of the patio (where the shed shall be laid) it has now taken the colour out of the slabs and left them greyish white. What should I do next?

[Dave]

Hi lucy..


It is water bloom... and needs removing

but the use of acid will make it worse.. and grey the slabs..

You need to use LTP Grimex and give the slabs a good clean.... then leave to dry , once dry then use 2 coats of LTP stone oil and then 2 coats of LTP colour enhancer , this should give you a really nice finish.

[lucysummers]

Thanks dave for your speedy reply, when you mean the colour enhancer is that the intensifier or the mattstone product? I notice there are 2 mattstones one with H2o so which is best to use? As I mentioned we only applied the acidy stuff to the top area of the patio which seperated by a step from the bottom half of the patio, which we also sealed and has the whitemarks on but we didnt put the acid cleaner on this bit thank god, so this part of the patio still has the thompsons sealer on it with white marks, should I treat this area the sames as the top area? Its only the top area of the patio that we cleansed to see how it would come up and this is where the limestone has gone grey so the process that you have mentioned above should i do it on the whole of the patio regardless? It has cost us £4000 and at the moment I feel distraut with the whole thing, I feel as though it is ruined, I wanted to post some pictures to show you but not sure how to on here

[lucysummers]

IMG00378-20110701-0755.jpgIMG00373-20110629-0806.jpgthis photo is how it looked before with marks on


this is the top bit of
patio that we cleaned

[Dave]

Morning

I have a method statement on the main pc, I will post it once I get on that later but yes it can be saved


Sent from my iPhone

[lucysummers]

hi Dave, much appreciated, please can you tell me what I should be applying to the top patio thats has been sealed, then went patchy and now has been washed with acid and lost its colour and B, what i should do with the bottom patio that was also sealed at the same time but is covered with marks also but hasnt been washed with the acid. Plus the method, pulling my hair out! I have located a place close to home where I can get the products, thanks Lucy

[Dave]

It needs removing , I will switch the pc on and post the method
Sat in garden at present


Sent from my iPhone

[lucysummers]

ok thank you so much, off to get the grimex this afternoon, enjoy the sun

[Dave]

Hi Lucy..

This is a method statement from LTP for the cleaning of a patio just like yours with same acid washing etc...

Wash surfaces thoroughly with a strong solution of LTP Grimex. This will help to break down and remove the sealer from the stone.

Use undiluted onto the surface of the granite and then agitate immediately using a black pad or stiff brush, adding a little water whilst scrubbing. Do this for 20 - 30 minutes and rinse well with plenty of clean fresh water. Leave to dry 30 minutes.

While the stone is still saturated with moisture we would suggest then washing the surface of the stone with a medium strength solution of acid in an attempt to even the discoloration of the stone caused by acid etching from the cement cleaners that were used.

Apply a 1 : 3 solution of LTP Grout Stain remover to the surface of the stone and scrub evenly over the surface, Leave for 5 minutes, agitate again and then rinse thoroughly with plenty of clean fresh water.

Leave to dry for 48 - 72 hours.

To help restore the colour of the stone we would like to suggest LTP Stone Oil to deepen the colour followed by LTP Colour Intensifier for extra protection.

Apply these products first in an inconspicuous area to help establish the optimum number of coats. Probably Stone Oil 2, Colour Intensifier 2.

Allow 4 hours drying time between each application.

[lucysummers]

thanks Dave should i follow this process to for the bottom part of the patio, which is also stained with watermarks, but wasnt cleanes with the acidy stuff, its just got the sealant on put i think we need to start from scratch. Just looked at another post from april that you replied to 'is my patio ruined' and her pictures are amazing, thank you

[Dave]

Just follow the above and if any product info needed then contact LTP and ask for mark and he will talk you through each process

Sent from my iPhone

[lucysummers]

thanks

[user123]

Good luck, Lucy, Dave knows his stuff, and I can image how much you want this sorting.

[lucysummers]

cant tell you how I am feeling right now, havent slept all week, gutted! Hope it will get sorted, thanks for your kind words

[jay]

as Dave says its fixable

[lucysummers]

hi Dave, managed to use the grimex today on the top patio where the acid was, no change there,but we thought there wouldnt be anyway as the patio cleaner with the acid has probably removed the sealant,(the only problem here is the lack of colour, the greyish white) so now we need to do the next process with the stone oil. The bottom area of the patio where the marks were, have lifted and we can see a result, but not sure if the one coat of thompsons sealant has been fully removed, so would it be worthwhile cleaning bottom patio again? Or do we put the stone oil on these followed by the colour intesifier or because these havent been touched with the original patio cleaner and still remain dark do we just apply the colour intensifier?

[Dave]

Yes, you do need to make sure you have removed the thompsons sealer fully.. even if it means a mild solution of what you used before.. once cleaned the stone oil will work.. followed by the colour enhancer to give a lasting seal.

[lucysummers]

thanks Dave, the top patio, where the patio/acid cleaner was applied, I dont think that will come up anymore, and we have applied the Grimex to this area also, I guess the acid would have removed all the sealant of that, as its definately took the colour, so when its dry and we get some nice weather (as I think its heavy rain all week) and it has dried out, should I just brush it down and proceed with the stone oil? I think we are going to concetrate on the top patio first and get that right! Thanks for your sound advice, Lucy

[Dave]

As long as it is dry then ye.. sounds good to me.

[lucysummers]

Hi Dave, have applied the stone oil yesterday and already its looking great! Not sure whether to apply another coat or just go on to use the colour intensifier as I am quite happy with the colour that they have come out and dont really want them any darker! So is it ok to apply just one coat of the oil? I have noticed tonight that the flags feel quite sticky so not sure what to do about that, any suggestions? I am hoping to get some good weather so i can do the colout intensifier, if this doesnt get done in the next couple of days, could the rain harm the stone oil on the flags?

[lucysummers]

IMG00395-20110712-0753.jpgIMG00396-20110712-0754.jpgafter stone oil applied

[nicolacodling]

hi,

I have had the same problem today!
Should I follow your instructions?

[Dave]

hi,

I have had the same problem today!
Should I follow your instructions?

No!... Contact LTP first , as they have changed spec..

[nicolacodling]

Ok, will do. Do you know why it would have done it? As on homebase and B&Q website, no one else has had any problems

[Dave]

Ok, will do. Do you know why it would have done it? As on homebase and B&Q website, no one else has had any problems

What was yours sealed with.?

[nicolacodling]

Thomspons water seal ultra on Ventura paving slabs