"Fred Williams" wrote:

I just cleaned out the unsightly moss from between the stones
on our walkway. It would be nice to have a filler between the
stones to make it look nicer, but it would have to be porous
else we'd have a flood after a heavy downpour. Any suggestions?

Pavers are supposed to butt up to each other with about 1/8" space,
maintained by a couple of bumps molded into the blocks. Pavers should
be set onto a densely compacted base of fine pointing sand about 6"
deep and then the same pointing sand broom swept into the small spaces
regularly over a full season or two. When done correctly there should
be no weeds whatsoever. If your blocks are set on ordinary soil and
with large spaces inbetween then you have no chance of weed free,
none. In order to not have puddling your area needs to be properly
pitched (1/4" per ft).