We put the patio in about 30+ years ago. It was looking beautiful with white rock in between the slabs, but as years went by we began to have grass & weeds growing up through the rock, so OUT went the rock & then we tried QUICK CRETE which is pictured in the BEFORE picture
I sifted the debris first through a milk crate & then through 1/2 inch screen.
I dug down 2 inches to the weed barrier cloth & then painted the slabs to match our deck. We added rocks again called BEACH WOOD stone , but this time we’ve learned how to vacuum the dirt out & we will keep it sprayed for weeds. I’m to old to do this again!