icornish wrote:
Have a block paving driveway on my property (came with the house).
Seems to be just sand between the blocks, though now it is more sand
and weeds.
Can I brush out the sand, and use weedkiller then use a dry mix of sand
and cement to "seal" the gaps between the blocks ?

Also, I have some slabs in the patio - is it recommended to fill the
gaps between these with a dry mix of sand and cement ?

TIA

Block paving works with friction and you're not supposed to use cement.
I've heard some say to use a very light cement mix to sprinkle over the
top to help seal the sand in but I don't go near the stuff.

For patio slabs you should use a sand and cement mix. If you're using
it dry then first drench the joints with water then make good as it
sets as you would brick pointing.