Best course of action for realising dot dab used - When or if to seal

[angus!]

Hi All,

Thanks for help in advance,

I have just realised that my landscaper has used the dot and dab to do our lraj green sandfstone honed sawn paving.

The paving has not been sealed yet and neither mortared the joints yet, as i said i would brush in the jointex mortor that I supplied.

Im worried about the flags staining through the mirroring action should I seal the paving to try prevent this issue? As it seems from the diagram on paving expert that its more the water travelling through the stones surface that can cause this kind of wicking action, therefore a moisture blocking seal should help no? the slabs are on a middle tier of a garden with good drainage and sloping slightly

I've purchased everbuild's "resiblock" sandstone invisible.

I guess the preventative measure should have been to seal them on the otherside, but as they are all down I'm a bit stuck.

Thanks for your help !

[jactac]

Hi there,
I had two patio's laid over the last 18 months by 2 different builders, both patios are Indian Sand Stone, one was laid "Dot & Dab" the other on a solid base.
The first patio, (Dot & Dab") looked great for many many many months so after waiting for about 6 months and seeing no staining coming through I decided to seal them (Smart Seal with colour enhancer).
Its now about 15 months since this patio was laid and it has clearly started to show circles coming through the stone.

I might reseal as I've read this tends to darken the colours and tone down the circles, however I've just resealed the other patio (on the solid base) after only 6 months of already being sealed, due to a different issue, and I'm now having an issue with the sealer leaving residue on top of the stone, (see other thread).
So trying to hide staining on an already sealed stone has not been successful in my case .

Basically getting back to your question, I thought I was safe by waiting to see if the Dot & Dab wouldnt show through, I waited months be applying a sealer, but over a year later you can clearly see the circles appearing, sealing does tone it down but doesnt hide it completely, in fact some of the staining seems to show up more after sealing !
Like you I didnt think of sealing the under side before having them laid.

[angus!]

Thanks so much for taking the time to reply, sorry to hear of your issues too. Can I ask what type of sandstone paving you used, colour and finish?

I'm thinking now to save the hassle and future worry as its only a 14m2 paving, getting another contractor to take up the paving, while its still fresh and re-lay on a full bed of mortar. I actually have the landscaper still on site, he has done a lot of other jobs too which are great, so I kind of don't have the heart to tell him, as he only has one day left, the job has already taken longer then what he has quoted for but I did agree to pay him an extra day. Prehap's I should pay him to re-do it on a full bed? I would not think it would take more than two days. Did you make contact with the landscaper with you concerns?

[jactac]

I used Indian Raj Green Sand stone on the Dot/Dab (36m2), and I think it was called Autumn Brown on the solid base, again Indian Sandstone (20m2).
If I'm honest both colours look the bloody same to me, with or without sealing.
The sealer I used was Smart Seal Natural Stone sealer and colour enhancer.
www.smartseal.co.uk/sealers/patio-seale ... ancer-.htm

It looks great when it on, but like I say it wont fully hide the Dot/Dab staining.
Also on our other patio (solid base), which was laid only 5 months ago I made the stupid mistake of trying to remove some efflorescence staining in the pointing by using diluted acid brick cleaner.
This slightly seeped into the stone and caused some staining, nothing bad but I knew it was there so wanted it gone, so I decided to try re-sealing the slabs yesterday, all was fine, the sealer seemed to soak in and the stone looked great last night, however it has rained over night and this morning theres a milky residue all over the slabs under the surface rain water, the was no residue showing last night, in fact the stone felt and looked dry to the touch, so I'm not sure why this residue has appeared ?

I've a feeling the rain has drawn it out onto the surface as it couldnt fully soak in because it had been previously sealed ?
Looking now I guess to remove the sealer and start again !
I'm hoping for some advice from this site ?

[jactac]

I have to say that even the patio laid on the full slab, one or two of the slabs are showing staining coming through.
It seems to be certain colours of slab that become more effected than others .

On the patio that was laid on Dot/Dab some of the slabs havent stained at all.

My guess is that staining seeping through might have a lot to do with how the cement/sand is mixed, it's not just a case of laying on a solid bed and things will be perfect ?

[angus!]

I did see on a post here under "flags and slabs" where someone of stature recommended using a cleaning company who have industrial size steam cleaner and set it at a high 120c, they used to use a product for year which was no discontinued. Someone also said that the cleaning company they contacted where confident they could remove it, and quoted a costing.

[jactac]

There are products to remove sealer, but apparently its messy and time consuming.
I've contacted the sealer company for advice and waiting their reply.

I dont think any amount of cleaning or products will remove Dot/Dab staining as its the salts in the sand and the cement being drawn up through the slabs .
The stains on my patio that was laid on Dot/Dab didnt start appearing for around 12 months.

[seanandruby]

i take it you have read this page
Scroll down until you see a link to reflective staining and click on it.
Laying on a full bed with a bond bridge of SBR would of been a better option. Your installer needs to sit and read this site before carrying out any more paving. Don't know if cleaning, or sealing will be of help but Roger will be along soon and advice you more on this.

[RAPressureWashing]

No amount of cleaning or removing the sealer etc is going to get rid of the dot & dab staining, it's all the way through the stone.

[jactac]

100% agree.

Like I said previously, I've had 2 patios laid over 18 months, one on DOT/DAB the other on a solid slab.
Both have staining but for different reasons, the DOT/DAB is down to the cement mix being drawn up through the porous Indian Sand Stone, leaving circular patterns in the slabs, which started to appear between 8 and 12 months.
Nothing gets rid of these types of stains, but a colour enhancing sealer tended to tone them down a little bit, still visible though to be honest.

The staining on the patio with a solid base was human error by myself by using a diluted mix of brick acid and water to try to remove salt bleeding out of the jointing, this left a slight staining around the edges, (should of left it alone or used a salt remover product), anyway I tried adding a further coat of sealer hoping it might tone down the staining but unfortunately (again human error) this application did not fully soak in due to the slabs already having a coat of sealer applied a few months ago, plus after putting on the 2nd coat it rained a few hours later, resulting in milky white patches.

Looks like this will need removing somehow ?
As for the DOT/DAB circular staining on the other patio, well it's there until the patio is ripped up and done again, only good thing is that the slabs are all different colours and shades so most of the circular stains look a bit camouflaged !

[lutonlagerlout]

Jactac I have edited your duplicate posts for clarity :;):

and the OP Angus

rip it up and start again ,with somebody who knows what they are doing

jointing or sealing now will only lead to more problems down the line

cheers LLL