Andrew Construction Co. II, Inc.

Concrete flatwork covers everything flat and horizontal: garage and shop slabs, patios, sidewalks, equipment pads and aprons. Most of what determines whether a slab lasts happens before the truck arrives. The subgrade is compacted, a gravel base of about four inches is placed and compacted, forms are set to grade with slope away from the building, and reinforcement, typically wire mesh or #3 or #4 rebar on chairs, is placed. Residential slabs are usually four inches thick and poured at 3,000 to 4,000 psi; anything that will see trucks or equipment goes to five or six inches. Control joints are cut at intervals of roughly two to three times the slab thickness in feet, so about every eight to twelve feet on a four-inch slab, because concrete will crack somewhere and joints tell it where. Concrete needs about seven days before foot traffic and twenty-eight to reach design strength.

Excavation contractors dig and move earth for foundations, basements, utilities, pools and site cuts. Most residential jobs run on a mini or mid-size excavator paired with a skid steer and a dump truck; larger cuts bring in a dozer or scraper. The price depends less on the size of the hole than on what is in the ground: clay, ledge rock, high groundwater and buried utilities all slow the machine down and change the hauling math. Before the bucket touches dirt the site needs an 811 utility locate, and any trench deeper than five feet needs a protective system under OSHA rules.

Grading is the shaping of ground to a designed elevation and slope. Rough grading moves the bulk of the earth to bring a site close to plan; finish grading dials in the last few inches so a pad is level and a yard sheds water. The number that matters is fall: building codes call for the ground to drop at least six inches in the first ten feet away from a foundation, and a lawn or gravel area needs roughly a two percent slope to drain. Crews do this with a dozer, a skid steer with a grading bar, or a motor grader on larger lots, checked against a laser or GPS grade stake rather than by eye.

Pond and water management contractors excavate and shape ponds, build or repair the embankment dams that hold them, and cut the ditches, swales and channels that move water across a property. A pond that holds water starts with the soil: it needs a clay core or a compacted clay liner, or a synthetic liner where the ground is sandy or rocky, and the dam is built in compacted lifts with a keyway cut into the original ground. Every pond also needs a way to pass the big storm, usually a principal spillway pipe plus an emergency spillway cut in natural ground, sized for the watershed above it. USDA NRCS publishes free design standards for farm ponds that most contractors follow. Cleanouts, which remove years of silt and reshape banks, are common on older ponds and are priced by the cubic yard removed and where that muck can be spread.

Septic contractors install and replace the tank, distribution box and drain field that treat wastewater on properties without sewer. Nothing goes in the ground until a soil evaluation or percolation test has been done and the county or state health department has approved a system design; the installer builds to that design and the inspector looks at the open trenches before they are covered. Conventional gravel-and-pipe drain fields are the least expensive where soil drains well, but heavy clay, high water tables and small lots push jobs toward chambers, sand mounds, drip dispersal or an aerobic treatment unit, each with a different price and maintenance schedule. Most states license septic installers separately from general contractors, and many require a pumping and inspection record at property sale.

Trenching and underground utility contractors open the ground for pipe and conduit, bed and backfill it, and put the surface back. What looks like a straight line on a plan is governed by a few hard numbers: 811 locates before any digging, a minimum cover depth that varies by utility (commonly 18 to 24 inches for electric and gas service, and below the frost line for water), and OSHA's requirement that any trench five feet or deeper have a protective system such as a trench box, shoring or a sloped wall, with a competent person on site. Bedding material under the pipe, compaction of the backfill in lifts and tracer wire on non-metallic pipe are the details that separate a line that lasts fifty years from one that settles and cracks the driveway above it.