Sealing sandstone - Top, bottom and sides?

Patio flagstones (slabs), concrete flags, stone flags including yorkstone and imported flagstones.
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deegan1979
Posts: 99
Joined: Tue May 19, 2015 2:04 pm
Location: kent

Post: # 104481Post deegan1979

Hi guys, I was led to believe from reading on here that sandstone should only be sealed on the surface, however the sealer I am using ( aqua mix ) their website recommends sealing all 6 faces, top bottom and sides.
I believed this would stop the slab bonding to the bed ( wet bed) and stop the pointing bonding to it ( using weatherpoint 365 )
Can anyone offer any advice please?
Thanks luke
Tellytubby

London Stone Paving
Posts: 2199
Joined: Mon May 10, 2010 1:07 pm
Location: Surrey
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Post: # 104517Post London Stone Paving

When we built our first showroom I installed some sawn Indian sandstone and decided to seal the underside. The result was that the slabs didn't bond to the mortar bed and had to be replaced after a few months.

Its not rocket science, sealants are designed to prevent water absorption into the stone. Water absorption into the underside of the slabs from the bedding layer is a key part of the bonding process. Using sealants on the underside of slabs will prevent this process from taking place and therefore completely compromise the bond.

Would be interested to know why your supplier is giving that advice

Steve

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