Concrete Driveway and Patio Contractor in Maricopa County, AZ

Gravelly desert soil on the fans and terraces of the Valley floor, often with a layer of caliche, soil cemented hard by calcium carbonate or silica, anywhere from a few inches to a few feet down. Caliche does not dig like dirt, and it does not drain like it either.

Dig to firm ground, break out caliche that sits high in the base and haul it off the site, bring in aggregate base compacted in lifts, and slope the slab and the grade so roof and sprinkler water run away from it and off the hardpan.

Layered silt, sand and gravel laid down by the Salt River and the desert washes, across the flood plains and alluvial fans of the central and west Valley. Most river and wash soil drains well and swells very little.

Compaction done in lifts at the right moisture, with loose or soft soil dug out and replaced, a thicker section anywhere a truck, trailer or RV will park, and grading that keeps runoff off the slab and out from under it. Washes and drainage easements stay open.

Pockets of clay-rich soil on the fan terraces and old basin floor that the soil survey flags for shrink-swell, such as the Carefree and Contine soils. Expansive clay swells when it gets wet and shrinks as it dries.

Remove the soft and organic soil, bring in compacted aggregate base, set rebar on chairs, and keep the moisture under the slab steady: drainage away from it, and turf and drip lines held back from its edges.

Sloped lots on and around the Valley’s mountains, where thin, stony soil sits on bedrock or hardpan: granite that weathers to coarse sand in the McDowells, older schist in the Phoenix Mountains, and volcanic rock in parts of the north Valley hills. On these lots the trouble is grade and water more than the soil itself.

Excavation into the rock or hardpan, a thicker compacted base where the support is uneven, drainage that catches runoff above the slab and carries it around, and engineered retaining walls where the grade is cut. Walls on hillside lots often need a permit, and each city and town has its own rules, so we check yours.