25sqm kota black patio laid and now?

[mikstik]

I dont know the difference between sandstone and limestone,
but lets say its kota black limestone
laid on 6in of crush'n'run compacted
1in of merseygrit sand very blinding layer
stones set on a full bed of 4:1 merseygrit and cement
the backs of the stones were pva'd
joints of 7mm

I want to use gftk's vdw840 polymeric sand to point the joints.
I want to seal the patio for that rained on look and to protect from stains.
I phoned NCC who supply the vdw840 and asked should I seal first then point and he said he would do it that way round

question - would you seal now (few days after laying) or wait for potential efflorescence to show? the family are desperate to use the patio.
and would you use lithofin stainstop outside? or another product
and would the lithofin effect the polymeric sand
and where in the mersey region would you get the lithofin or just ebay it
any input grately appreciated

ps the polymeric sand; is it water proof, does it matter with a full motar bed below?

[Tony McC]

Kotah Black is limestone. There is almost nop risk of it being affected by efflorescence unless the cement content from the bed was to find its way to the surface.

The 840 is a suitable product for jointing patios (not driveways or any other heavier-than-a-child's-bike applications). Jointing will leave a *temporary* wet-look film on the surface.

If you seal first, you need to allow 3-7 days for the sealant to 'cure' before applying the jointing. I'm not sure how the resin used in VDW products reacts with the resins in StainStop, so my inclination would be to joint first, allow a few weeks for the jointing residue film to weather away, and then seal. In the meantime, I would very definitely treat the flagstones with the Colour Impregnator, because that limestone is notorious for bleaching. You might as well get on a treatment or two of the colour impregnator to build up the depth of colour to a satisfactory level before making it permanent by applying the final coat of StainStop.