A 20x30 slab is 600 square feet, and in Winston-Salem, NC it is the workhorse size: detached workshops, carports, RV and boat pads, and big entertaining patios all land near this footprint. At this size the economics flip from small-pad pricing: the fixed crew costs spread thin across 600 feet, so the per-foot rate is among the best you will see, and the questions that matter become what the slab has to carry and what the ground under it looks like. A furniture patio, an RV pad and a workshop floor at the same 20x30 are three different specs with three different prices. Tell us which one it is and the written estimate prices that slab, not a generic one.
Updated Aug 31, 2026 · Winston-Salem Concrete Co, Winston-Salem, NC
What the slab carries decides the spec. A 20x30 entertaining patio is a 4 inch pour with a broom or decorative finish. An RV pad carries several tons on wheels parked in one spot for months, so it wants more thickness or reinforcement and a base compacted to match. A workshop floor is a garage-grade pour: vapor barrier, hard trowel finish, thickened edges if walls are coming. Pricing them the same would mean one of them is specified wrong.
This is the page where honesty about use matters most. Tell the estimator a patio and park a camper on it, and the slab was built for the wrong job. The spec conversation at the estimate visit is exactly this: what is the heaviest thing this slab will ever hold.
At 20x30 the site preparation is a real earthworks task. The platform has to be level and compacted across its whole area, and most Winston-Salem yards big enough for this slab have grade to deal with. Expect cut on one side and built-up compacted fill on the other. Drainage planning matters at this scale too: 600 square feet of concrete sheds a lot of water somewhere, and where that water goes is designed before the pour, not discovered after. On truck access, a 20x30 at 4 inches is roughly seven and a half cubic yards, a full truck plus, and a location the truck cannot reach adds pumping.
The spread between 20x30 bids comes from a short list.
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