Concrete – Gravel patches in concrete after sanding

Crushed concrete is a very good substrate for a slab. The key is to not have chunks so large that air pockets are created. Maybe bring in a layer of sand to fill the voids and level things a bit. A water rinse will help bring air out and compact the material.

I have seen this done in better and worse ways.

• using sand as the topper is an invitation for ants to make a new home, stone dust is a better choice
• what's under the gravel affects how long the job lasts as much as drainage. In colder areas clay soil will heave and push the slabs out of true. Leveling the slabs every spring quickly looses appeal. For slow draining soils or areas where lots of water is expected to drain a base of 6 to 12 inches 5/8" crushed gravel compacted in layers with a compacter topped with an inch to two of stone dust to level is better.
• at all costs you want to keep water away from your foundation. This is determined by your roof. How far out do the eaves extend and do you have gutters?
• Without gutters slabs that are slightly tilted away from the house can control water. It does become critical that the slabs continue to slope away from the house or you are worse off than if you had left the surface at grass
• with gutters my favorite tool of four inch drain pipe with sleeve buried six inches below the surface is an excellent way to channel water from the gutters away from the house