The patio blocks around our pool are uneven due to roots and 30 years
of wear.

I am planning to pick them up, relevel and rescreed and re-lay them.

They were originally put down with 3/8" mortared joints (probably dry
mortar mix and misted).

I was wondering how much difference there would be in water intrusion
through the pavers if I put them back without the mortar. I've found
that a handheld air hammer will take the old mortar off very cleanly.
I'm thinking that might even be a little more watertight than if the
mortar joints crack.

I need this job to last about 3 or 4 years. My plan is to replace the
pavers, then paint over them with an acrylic paint with nonskid.

I can recalc the size to make up for the loss of the mortar joints.

Also, I had thought of putting plastic under the sand or perhaps
between the sand and the pavers but that seems like it might cause
problems.

One final question. I'm assuming that 1/4 inch per foot would be
sufficient. There are parts where it's about 1" in 1 foot right now.

Thanks, I'd really appreciate any input.

cg