Everybody sees the finished concrete. The driveway. The patio. The sidewalk. The garage slab. The smooth surface. The clean edges. The nice finish. But what most people do not see is the part underneath it — and that hidden layer can make or break the whole job. That layer is called the subbase. At GM Foundations Plus, we believe strong concrete starts before the concrete truck ever shows up. The finished surface matters, but the prep underneath matters just as much. Because