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Posted: Tue Jun 05, 2018 7:57 pm
by Sar
Evening,

I have had a patio laid in Bradstones Natural Sandstone Burnt Umber flags. It didnt take long for the blotches to appear for me to find out that dot and dab shouldnt have been used for any kind of stone but especially not sandstone. To say im disappointed is an understatement

I have been recommended the guy who laid the patio and he is an acquaintance of mine, however, he is a property maintenance and small building works type (who has done quite a few patios) rather than specialist patio man and has never heard of this issue and has always dot and dabbed patios. Lessons learnt all round, I have lifted the flags.

How to proceed? The patio will take approx 35 slabs to complete, I have 10 which are not used and therefore not stained as I over ordered to created stepping stones around the garden. I need to re-lay the patio with these stained stones. Questions:

1. Is there any way this staining can be removed for the used and now lifted slabs?
2. Will laying them on a full mortar bed cause the entire stone to effloresce evenly and therefore the stains to remove/apply equally across the stone?
3. Should it be a full wet mortar bed? Sand? The major DIY chains websites show dot and dab, or no mortar bed at all....?
3a. There are still very small (few mm deep) voids under the ones laid on the full mortar bed - what has gone wrong here and what do I need to tell him to do.
4. Should the pointing be done with anything other than mortar.

Also, how easy should it be to lift slabs, Im no weakling but im surprised how easy it was. Even the ones that have been laid on a full mortar bed I was able to just lift it up, a few needed a bit of a jimmy but still not much!, is this correct?

Apologies for all the questions, anything missing just let me know.

Wish I just went with a deck and did it myself now, or even just learned to lay a patio and did it myself.
:(

Posted: Wed Jun 06, 2018 6:16 am
by Sar
Ive spent some more time reading around the site and taken more of the information in. Please correct me if Im wrong on the below and also answer q's 3a and 5...

1. Is there any way this staining can be removed for the used and now lifted slabs?
----Most likely ruined. Soaking them as I hoped may dissolve the salts in some way most likely wont work because they are now bound to the stone
2. Will laying them on a full mortar bed cause the entire stone to effloresce evenly and therefore the stains to remove/apply equally across the stone?
---Possibly, Im going to try anyway as I cant afford more stone. I have no recourse with the workman as he said he would 'dot and dab' many times and I didnt object because I didnt know any better.

3. Should it be a full wet mortar bed? Sand? The major DIY chains websites show dot and dab, or no mortar bed at all....?
---Mortar bed, try and minimise cement and water in the mix

3a. There are still very small (few mm deep) voids under the ones laid on the full mortar bed - what has gone wrong here and what do I need to tell him to do.

4. Should the pointing be done with anything other than mortar.
---No, point with mortar and the staining youre worried the workman will leave, if it arises, abrade it off.

5. Given that a colour enhancer 'may' help, and I wanted the colours enriched anyway....could you recommend a colour enhancer to use with this stone.

Many Thanks