Brick Paver Gap Filler . Sand between pavers once all the pavers are set in place, spread more sand over the top of them. Use a tool or your fingers to smooth the mix in the gap. Large Gap Between Foundation And Pavers. Fill With What? Concrete from www.diychatroom.com Consider making stone walkways in stepping stone fashion, with broad spaces between each stone to be filled with decorative gravel or sod. If you’re using bricks or stones as paving for a walkway, leave wider gaps. Put together a 4:1 (though some use 3:1) mix of builders sand and cement (do not mix with water!) brush across the whole area using a softer brush, filling all slab gaps evenly.