Most homeowners think the pour is the hard part. On our crews, the pour is the easy part. Everything that matters has already been decided by the time the truck backs up the driveway.
Why the Base Is Half the Job
Concrete is strong in compression and weak in tension. When the ground underneath the slab shifts — from frost heave, poor drainage, or uncompacted fill — the slab has to flex to stay whole. A flexing slab cracks. A slab sitting on four inches of compacted Class 5 aggregate over proper grade does not flex.
What Compacted Actually Means
Compacted means a plate compactor bounces off the surface. If you can make a footprint in the base, it is not compacted. We compact in lifts — two inches, plate, two more inches, plate — until the surface is solid enough that the compactor hops. A lot of crews skip this step because it adds hours to the job.
Grade, Drainage, and Vapor Barriers
The base gets graded away from structures so standing water never sits against the slab. Vapor barriers go in on interior floors where moisture migration is a concern — garage floors, basement slabs, workshop floors. Rigid foam goes in where the spec calls for thermal isolation.
Luck gets you through one winter. Prep gets you through twenty.