Post-tensioned concrete courts: when the extra money is worth it

Drive across the Sun Belt and most of the new tennis courts are concrete slabs pulled tight with steel cables. Drive across Northeast Ohio and nearly all of them are asphalt. The reasons are history and price, not physics, and as asphalt gets more expensive and clubs plan further ahead, the question comes up on more site walks: should this court be post-tensioned? Here is what the slab is, what it costs, and when I say yes.

What post-tensioning is

A concrete slab, four to five inches thick, poured over the stone base with steel cables in plastic sheaths running through it both ways at a few feet apart. After the concrete has cured for a week or so, each cable is stretched with a hydraulic jack and locked off at the edge of the slab, which squeezes the whole slab together with hundreds of tons of force. Concrete is weak in tension and strong in compression; a slab held in compression resists opening cracks, because any crack that tries to form is being pushed shut; the ASBA's word is that post-tensioning minimizes cracking, not that it ends it. The slab is one piece, 120 by 60 feet, with no joints for water to get into and no joints to heave.

Why it suits our ground

Asphalt courts here crack because the clay under them moves and the asphalt follows: a wet pocket heaves, a dry summer shrinks, and every crack is a path for the water that makes it worse. A post-tensioned slab is stiff enough to bridge small movements in the subgrade rather than follow them, and because it is compressed it does not crack when it does flex. It still needs a drained, compacted base and a frost consideration at the edges, and it is not immune to a bad subgrade; but the common Ohio failures, reflective cracking and frost-heave cracking, are much rarer on it.

How it plays and lasts

The same acrylic system goes on top, after the concrete has cured and been etched or primed, so the court plays like any hard court; a cushioned system can go on it too. The slab's planarity is set at the pour and does not drift the way asphalt can, so birdbaths are rare. A post-tensioned court properly built is a thirty-year-and-more slab by the claims of the firms that build them (no neutral study exists; the long-run record in the Sun Belt is the evidence); the color is renewed on the usual cycle and the crack repair line on the proposal is close to zero.

What it costs

More, up front. Concrete with cables, forming, the tensioning crew and the longer cure cost more than two lifts of asphalt, and in this region, where the concrete court crews are fewer, the premium is larger than in Texas. Over the court's life the arithmetic turns: no membrane repairs, no overlay at year twenty, no cracked-court resurfacing at year five. For an owner planning on forty years, a school, a club, a city, it is often the cheaper court. For an owner planning on ten, it is not.

The things to get right

• The base: compacted, drained and planar, like any court; a good slab on a bad base is a bad court.
• The edge: a thickened edge or a turned-down footing below frost where the slab meets the ground, so the perimeter does not heave.
• The cure: concrete needs weeks before coating, and the moisture in it has to be tested, not guessed; acrylic over damp concrete blisters.
• The net posts and fence: sleeved through the slab at the pour, not core-drilled through the cables later.
• The crew: cables are tensioned by people who do that for a living.

When I say yes

A new court, not a replacement surface. An owner with a forty-year view and the budget for the premium. A site with clay that has already cracked an asphalt court, or where an overlay has failed. A multi-court bank where the repair line on asphalt courts has been the biggest line in the budget. And pickleball banks, increasingly, because the courts are small, the slab is modest and the kitchen lines want a surface that stays true.

When I say asphalt

Resurfacing or overlaying an existing court. A budget that will not stretch. A site with difficult access for a concrete pump and the tensioning crew. A court that may be moved or repurposed. Most park courts, honestly, where the money does more good spread across more courts. Asphalt built properly, with the base and the drainage done right, is a fine court for thirty years; the site prep article is about building it that way.

Either way, we price both when the site allows it, and we tell you which we would build with our own money.