Site Survey & Soil Testing Before Court Construction

A court needs a flat, properly sloped pad — not a level one. ASBA's published construction guidelines call for finished grade sloped between roughly 0.83% and 1% across the footprint, sloped as a true plane rather than tilted end to end. You cannot eyeball that number on a backyard lot that looks flat to a homeowner walking it; a laser level or a formal topographic survey is what actually shows the inches of fall (or rise) across sixty feet of yard, and whether the natural grade already does most of the work or whether the pad needs real cut-and-fill to get there.

On a straightforward backyard lot, we run this as a grade check during the site visit — a laser level and a few reference shots across the proposed footprint tell us what we're working with. On a sloped lot, a lot with a retaining wall in play, or a multi-court project where the pad spans a bigger area, a formal topographic survey from a licensed surveyor gives us contour lines and elevations precise enough to design cut-and-fill volumes and a retaining plan before we price the job, instead of discovering the real grade mid-excavation.

The survey also answers a question a lot of homeowners do not think to ask until it is expensive: where does water on this lot go right now, before you touch anything? A court built without knowing that can end up as the low point that collects runoff from the rest of the yard, or it can shed water directly toward a foundation or a neighbor's property — both are problems a five-minute grade check on day one would have caught.

When we test-pit or auger a proposed court footprint before excavation, we're reading three things: soil type, moisture behavior, and compaction history. Expansive clays and organic soils are the two materials that most reliably cause problems later, because they move — clay shrinks and swells with wet and dry cycles, and buried organic material (old topsoil, roots, construction debris) decomposes and settles years after the court is built and the crew is long gone. Poorly compacted fill, especially on a lot where a prior owner filled in a low spot or an old pool, behaves the same way: it looks solid on day one and settles unevenly over the following seasons.

The tell for a subgrade that moved after construction is a pattern of interconnected fine cracks across a section of the court — sometimes called alligatoring because of the resemblance — as opposed to one or two isolated hairline cracks from ordinary surface wear. Alligatoring is a subsurface signal, not a surface one, and it is the reason a court that is only three or four years old and already showing a network of cracks usually needs an honest look at the base rather than another color coat. Our slab settlement and heave repair guide covers what that repair actually involves once it's already happened; this page is about not getting there in the first place.

A percolation test — the water-absorption-rate test used before installing a septic drain field — is not a permit requirement for a sport court, but the same underlying question matters: how fast does water move through this soil, and where does it go when it doesn't? On a lot with a septic system, we ask for the original perc test results filed with the county health department; they tell us the site's general drainage character without paying for a new test. On a lot without that data, and especially one with a history of standing water or a high water table, that is when we recommend budgeting for a proper geotechnical evaluation rather than guessing.

Site survey and soil evaluation happen before we finalize a quote, because they change the quote. A lot that only needs standard excavation and compacted fill costs meaningfully less than one that needs over-excavation, geotextile fabric, or engineered fill to get a stable subgrade. That's a different conversation than the one in our base preparation and grading cost guide, which covers what the base itself costs once we know what we're building it on — this page is the step that determines which version of that job you actually need.

Some NJ lots make this an obvious, upfront conversation rather than a hidden one: sandy or loose soils along the Shore and Pinelands regions, and heavy wet clay on inland lots, are common enough that we cover them as their own topics. If your site has visible standing water, a marshy low spot, or soil that stays soft well after a rain, our building on sandy or wet soil guide goes deeper into what changes in the base design. And because soil type and drainage design are two sides of the same problem, our court drainage systems guide covers what happens above the subgrade once we know what's below it.

Once the base is designed around the right subgrade information, the next construction decision that affects long-term cracking is how the concrete or asphalt itself handles temperature movement — that's a separate question from the soil underneath it. See our guide to control joints and expansion joints in court construction for how post-tension concrete, reinforced concrete, and asphalt each manage that movement differently.