We have a large sawn mint sandstone patio which we had laid in 2016. We have had endless issues with is (efflorescense and moisture trapped under sealant, staining due to being so porous). We have finally rectified all of these issues thanks to some really helpful advice given on this forum (🙏) to remove sealant and we now have no sealant on it. Stains easily but just dealing with it through frequent maintenance.
However, typically, just as we get it looking good four years later, we are just about to have an extension built and we are having to pull up the patio and are having part of it relayed using some cleaned off slabs and some slabs we had left over from the original job. We are having this patio relayed on the previous patio to raise it to create a level threshold.out of the extension (raised by about 7 inches)
We can't push the budget to new slabs (although that would be ideal!) and additionally we have 5 steps stretching across the width of the garden in the slabs and don't want to replace these.
So, we are now trying to prevent all the issues we had first time around with the slabs.
The retailer of the slabs provides the following advice.
....
"IMPORTANT: Sawn Mint is porous and requires sealing. We recommend a stronger sealant such as Lithofin Stain Stop Plus, with a minimum of 2-3 coats, until no more sealant can be absorbed. All sawn paving needs sealing prior to laying with a natural stone sealant such as Geofix Natural Stone Protector (on all 6 sides - top, bottom and sides) or Dry Treat (top side only). Sawn paving can stain easily before sealing. Avoid using any acids to clean natural stone paving"
Our builder last time said this was nonsense as would mean the slabs would not adhere to the mortar bed. And there in (I think) lied the issue....the slabs needed sealing before but this wasn't possible...
So my question is...should we seal as per retailers advice before laying or is this daft? Or should we just leave the slabs unsealed for a year or two...and just deal with the high maintainance from not sealing?
Also....is pointing with mortar likely to reduce issues with moisture....the builder last time used weather point 365 (which I hate as it's always coming out...not aided by the amount of pressure washing required!)
Finally...any advice on the best sand/concrete to use to prevent discolouring/eff?
Many, many thanks in advance!
Dean 👍
Getting it right 2nd time around! - The perils of sawn mint sandstone
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Tony McC
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GeoFix!!! Aaaaarrrrggghhh! Never. Ever. EVER! The jointing jollop is truly awful and that should be your guide regarding the efficacy of their sealants!
With what you will need to spend on *quality* sealing and protection products, you could near enough buy a new, far superior stone to <spit> Mint, but if you are intent on re-using it to save on landfill costs, I'd look at sealing all six sides (and getting that done without streaking or blotching is a job in itself!) and then relying on a proven Bond Bridge Slurry Primer to ensure adhesion between flags and bedding.
Lithofin and Dry Treat are both good brands, but I'm not certain they are necessarily the best for the abomination/over-priced hardcore that is Mint. I'd speak to a trusted manufacturer, say James at Extensive or Mark at LTP/Ecoprotec, and see what they suggest, which may not actually be one of their own products, as they are both mnore concerned about getting the right product for the application in hand rather than selling you 50 quids' worth of sealant that will have you banging on their door with problems in a months' time.
With what you will need to spend on *quality* sealing and protection products, you could near enough buy a new, far superior stone to <spit> Mint, but if you are intent on re-using it to save on landfill costs, I'd look at sealing all six sides (and getting that done without streaking or blotching is a job in itself!) and then relying on a proven Bond Bridge Slurry Primer to ensure adhesion between flags and bedding.
Lithofin and Dry Treat are both good brands, but I'm not certain they are necessarily the best for the abomination/over-priced hardcore that is Mint. I'd speak to a trusted manufacturer, say James at Extensive or Mark at LTP/Ecoprotec, and see what they suggest, which may not actually be one of their own products, as they are both mnore concerned about getting the right product for the application in hand rather than selling you 50 quids' worth of sealant that will have you banging on their door with problems in a months' time.
Site Agent - Pavingexpert
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MikeG
- Posts: 16
- Joined: Wed Jul 04, 2018 11:33 pm
- Location: Dorset
I laid some sawn mint a few years ago which hadn’t been sealed. I made sure that before laying the slabs they were thoroughly saturated until they could take no more water so that they would drink up as little as possible from the bedding mix.
They came out with only very slight taint of discolouration which the customer said he quite liked. ( possibly because he had bought them ..... special offer )
The only other things I would say if your not sealing them is use a light coloured cement and sand.
Don’t have the bedding mix overly wet.
If you are mortar pointing then point as you go with a damp mix that would draw from the bedding mix if it requires a bit more moisture.
Do all of the above in a small test area and wait for a week to see if your happy with the result.
They came out with only very slight taint of discolouration which the customer said he quite liked. ( possibly because he had bought them ..... special offer )
The only other things I would say if your not sealing them is use a light coloured cement and sand.
Don’t have the bedding mix overly wet.
If you are mortar pointing then point as you go with a damp mix that would draw from the bedding mix if it requires a bit more moisture.
Do all of the above in a small test area and wait for a week to see if your happy with the result.