Concrete Services in Waukee, Iowa — Your concrete, our crew, one contract

What is a new Waukee driveway or patio actually sitting on?

Clay-heavy ground: Des Moines Lobe glacial till, laid down by the last glacier. Building codes in the area put frost depth at 42 inches, and as this clay freezes it pushes up, then settles back when it thaws, which is why the base under a slab gets as much attention as the slab.

JLB compacts and grades that base so the concrete bears evenly, then matches the thickness to the load: four inches for a car driveway, and a thicker, reinforced slab where trucks, RVs or trailers will park. On a patio we add rebar or mesh where the load calls for it and saw-cut control joints, cuts that steer the shrinkage cracking every slab gets into clean, planned lines. On a wide or stamped patio, that joint layout is designed in from the start.

What do Waukee's standards ask of a new public sidewalk?

Sidewalk and driveway-approach work in the public right-of-way, the public strip along the street, goes through Waukee's "Right of Way or Utility Easement Permit, including Sidewalk/Approach." The city's Sidewalk Installation Design Standards then set out the walk itself. In the order a pour happens:

1. Base. Displaced material, soft spots and vegetation come out. Then 1 to 2 inches of aggregate goes down on a firm surface, tamped with at least a 50-pound hand tamper. Compacted 1-inch roadstone is acceptable; sand is not.
2. Forms and thickness. The walk is 4 feet wide, set 1 foot toward the street from the lot line, and at least 4 inches thick. Where a driveway crosses it, it's at least 6 inches thick or as thick as the driveway, whichever is greater. The concrete is Portland cement concrete, in the mix the standards call C-4.
3. Joints. Full-depth ½-inch expansion joints, gaps that let neighboring slabs move, go at property lines, where the walk meets a driveway or an existing slab, at the street, at the end of each workday, and wherever a pour stops for 30 minutes or more. Contraction joints, the cuts that tell the walk where to crack, are spaced at the sidewalk's width.
4. Slope. Side-to-side tilt is ¼ inch per foot by preference, and ½ inch per foot at most.
5. Curing. Liquid curing compound goes on undiluted, at 0.03 gallons per square yard.