Arizona Sitework & Excavation Contractors

Because the base and subgrade carry the load and the asphalt spreads it. Pavement built on a weak or poorly compacted base fails from underneath regardless of how thick the surface is, and the failure shows up as alligator cracking, rutting, and potholes that keep coming back. Extra asphalt over a bad base buys a little time and a lot of cost.

The usual remedy is over-excavation: dig out the bad material and replace it with compacted aggregate, or stabilize it in place with lime or cement. Both cost money that was not in the base bid, which is exactly why the unit price for over-excavation should be in the proposal before the work starts. A bid with no such line item is a bid with an unpriced risk in it.

For most parking lot work, hiring one contractor who either self-performs or manages the earthwork is simpler and puts accountability in one place. Separate contracts make sense on larger projects with a general contractor coordinating, or where the earthwork substantially precedes the paving. What you want to avoid is two contracts with no one owning the interface between them, since that is where a soft subgrade becomes an argument.

Compaction testing, which is a standard construction service performed by a testing lab. The lab takes density readings against a laboratory standard for the material and issues a report. Specify testing in the contract and ask for the results. Without it, compaction is a claim about work that is now buried under asphalt.