- Q. When compacting a gravel base for a slab, how can you tell when the gravel is compact enough?
A.Jay Meunier responds: The only positive way is to have a Proctor test done. A Proctor test uses special equipment, which a soils engineering firm would have, to measure the percentage of compaction. Typically, though, if the compaction has been done using mechanical compactors in 8- to 12-inch lifts, the compaction should be adequate, as long as the soils underneath are good quality.
Jay Meunier is an estimator for Pizzagalli Construction in Burlington, Vt.