Pointing slabs - Is it best to point as you go?

[pop]

Hi can you help, I am laying a 35sqm patio with indian sandstone, is it better to point while I am laying the slabs, because I have been told that the mortar will mix better with the cement under the slabs. ie after a few days the cement will be hard and the mortar won,t blend. With possible crumbling?
Any help or view appreciated.
Cheers
Pop

[lutonlagerlout]

^^
LLL

[Tony McC]

Mix? Blend? I think you mean "bond".

Flags should be pointed within a few hours of laying, whener possible, bevcause, as you suspect, the pointing mortar will then BOND more effectively to the bed mortar and there's less risk of a day joint between the two.

However, it's not always possible to point on the same day, and it's not the end of the world if the joints are left empty for a short period. When the opportunity to complete the pointing does arise, the joints should be swept of blown clean, wetted down and allowed to dry off slightly before placing the pointing mortar.

Of course, with a polymeric or epoxy mortar, you just need to ensure the joints are clean.

[swanvesta]

Of course, with a polymeric or epoxy mortar, you just need to ensure the joints are clean.

Can I ask "how clean?" What if there's a bit of mortar on the edges, or a bit of sand/gravel in the bottom? I have read here that you can put a bit of sharp sand in the bottom of deep joints, where they are deeper than the prescribed 30mm. Does that mean the bottom of the joints can be loose?

Here's the background: I am a novice with a lot of interest but not enough time to do the whole job of installing our patio. I asked a handy friend/neighbour to lay our flags last week, telling him about the advice on this wonderful site. He told me he wouldn't be able to lay slabs on a semi-dry bed and insisted on using a 4:1 wet mix of sharp sand and cement. That seemed to go well enough, but unfortunately he buttered the chamfered edges of the flags with this mix and left a very variable depth for me to point. His explanation was that I'd told him I was going to use an expensive grout and he was saving me money. Which would be reasonable (assuming Romex will stick to mortar as well as it sticks to stone) if only it didn't look such a bleeding mess! Anyway, to be on the safe side I spent most of the weekend hacking about with a hammer and chisel, cleaning up the edges and raking out the joints that weren't deep enough.

Any further advice would be much appreciated.

[Tony McC]

Clean as in "free from dust, detritus, organic material and and other loose matter".

As long as you have 25-30mm depth, and 6mm or more width, you should be OK