Hiring a Concrete Contractor: The Questions That Matter

A Loudon Heights homeowner asked me last fall to look over a contract before she signed it, and the concrete work itself wasn’t the problem — the questions nobody had asked were. She’d gotten a price and a start date, and nothing else, no mention of soil conditions on a hillside lot where soil conditions decide most of what happens after the pour. Here’s the list I’d actually want answered before hiring anyone to pour flatwork, whether that’s me or someone else.

Where Does the Water Go

Ask where water on the lot ends up once the new slab is in place — which direction it drains, at what slope, and where it discharges. A driveway or patio poured without a clear answer to that question is a drainage problem waiting on the next hard rain, and on a Kanawha Valley hillside lot that answer matters more than the finish on the surface. If the answer involves a neighbor’s yard or a shared drainage swale, get that detail in writing before the pour, not after a complaint arrives.

How the Base Gets Handled

Ask what happens if the excavation turns up soft or unsuitable soil instead of the base material assumed in the bid. A contractor with a real answer — over-dig and replace with stone, add geotextile fabric, bring in additional compaction — has run into this before. A contractor who says it won’t happen hasn’t looked at enough ground yet. Ask, too, how that scenario would be priced if it happens, since an unplanned over-dig on an old filled lot is one of the more common reasons a job runs past its original number.

Mix, Reinforcement, and Joints

Ask what compressive strength and air content the concrete will be, and how the cubic yardage was calculated, since a slab priced by guesswork on volume tends to run short exactly when it’s least convenient to order a partial load. Ask when joints get cut after the pour and how far apart they’ll be spaced, since timing on saw-cutting affects whether the slab cracks along the joint or somewhere else entirely. Ask how curing is handled and for how many days, because a slab that dries too fast loses strength it never gets back.

Ask to See Old Work

Ask to see work that’s at least five years old, not last month’s photos. A driveway looks acceptable on day one regardless of who poured it; five winters of freeze-thaw and road salt is what actually shows whether the base was compacted and the mix had the right air content. If possible, ask for an address rather than a photo and go look at the joints and the edges yourself — a photo can hide a lot that a walk-by won’t.

Red Flags and What to Check

Three things I’d walk away from every time: pressure to sign a contract today to lock in a price, a request for payment in cash only with no invoice, and a flat statement that “nothing here needs a permit” without naming which jurisdiction was checked. Ask to see proof of general liability coverage and workers’ compensation, and ask whether the business is registered as a contractor with the state — OSHA publishes general information on jobsite safety responsibilities worth knowing before hiring anyone doing excavation or concrete work on your property, since a lot of the questions above trace back to the same underlying concern: does this crew do the boring parts correctly when nobody’s watching. Cross-reference whatever number you get against what a concrete quote should itemize so the answers to these questions show up in writing, not just in conversation.

Frequently asked questions

What’s the biggest red flag when hiring a concrete contractor? Pressure to sign immediately, cash-only payment with no invoice, and a claim that no permit is needed anywhere are the three most common warning signs.

Why does it matter how old the sample work is? Fresh concrete looks acceptable regardless of how it was built; several winters of freeze-thaw and de-icing salt reveal whether the base and mix were done correctly.

What insurance should a concrete contractor carry? General liability coverage and workers’ compensation are the two to ask about directly, along with whether the business is registered as a contractor with the state.

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Contents

  1. 01Sidewalk Flags and Vault Slabs in New York: Who Fixes What
  2. 02Basement Slabs on Georgia Red Clay: Vapor and Heave
  3. 03Frost Heave Under a Driveway in Northeast Wisconsin
  4. 04Driveway Slabs on Red Clay: What Actually Moves Them
  5. 05Paving in a Historic District: What You Can and Cannot Pour
  6. 06Steep Driveways: Traction, Drainage and Turnarounds
  7. 07Post-Tension or Rebar on Central Texas Clay
  8. 08Pool Decks and Salt: What Fails First in South Florida
  9. 09Why Driveways Crack at the Apron First
  10. 10Where a Slab Meets a Masonry Wall: Isolation Joints
  11. 11Limestone Paving in Central Texas: Sealing and Slip
  12. 12Brick-Paved Alleys and Driveways: What Keeps Them Flat
  13. 13Curb Cuts, Aprons and Where the City Line Falls
  14. 14Pouring on Caliche: What That Hardpan Does to a Slab
  15. 15Paver Driveways on a Hillside: Base Depth and Edge Restraint
  16. 16Why a Desert Garage Slab Still Fails a Moisture Test
  17. 17Grinding Versus Acid Etching Before a Garage Coating
  18. 18Tying an Addition Slab Into an Existing Foundation
  19. 19Slab or Piers Under a Sunroom: How to Choose
  20. 20Condenser Pads and Slab Penetrations in a Two-Family
  21. 21Equipment Pads in a Crawlspace and Why They Sink
  22. 22Where Roof Water Lands on a Driveway
  23. 23Moss, Shade and Slabs in the Willamette Valley
  24. 24Degreasing a Concrete Floor Before Anything Else
  25. 25De-Icer Residue on Warehouse Floors
  26. 26Thresholds and Trim: Where Timber Meets a Slab