Concrete Works Cost in Whitby

Excavate to the required depth (depends on application — driveways need 6-8 inches of base + 4-6 inches of concrete; footings per OBC need to be below frost line, typically 4 feet / 1.2 m). Compact the subgrade with a plate compactor to prevent settlement. Install 4-6 inches of clear gravel base (3/4-inch stone) for driveways and slabs — this provides drainage and a stable base. Compact the gravel in 2-inch lifts.

Build forms from 2x4 or 2x6 lumber, staked and braced to hold the concrete. Forms must be level (for slabs) or follow the designed slope (driveways need 2% slope for drainage). Install rebar or wire mesh per design — footings typically use #15M rebar at 400 mm O.C., slabs use 6x6 W1.4xW1.4 welded wire. Rebar must sit on chairs (plastic or metal supports) to position it in the middle third of the slab thickness.

Order ready-mix concrete from a supplier — specify strength (25-32 MPa for residential), slump (100-150 mm), air entrainment (5-7%), and aggregate size (20 mm max for most jobs). Pour starts at the farthest point and works backward. Consolidate the concrete with a vibrator (removes air pockets) or by tamping with a 2x4. Screed the surface (drag a straight edge across the forms to level it). Work quickly — concrete starts setting in 60-90 minutes.

After screeding, wait for bleed water to evaporate (sheen disappears from surface). Float the surface with a bull float (smooths and levels). For driveways, use a broom finish (drag a stiff broom across the surface for traction). For interior slabs, trowel smooth with a steel trowel. Cut or form control joints at 2-3x slab thickness in feet (4-inch slab = 8-12 ft spacing). Edge the perimeter with an edging tool to round the corners (prevents chipping).

Keep the concrete moist for 7 days minimum. Methods: (1) spray with water 3-4x per day, (2) cover with plastic sheeting or wet burlap, or (3) apply a liquid curing compound (spray-on membrane). In hot weather (> 25°C), mist the surface hourly to prevent rapid evaporation. In cold weather (< 10°C), use insulated blankets or heated enclosures. Concrete gains 50% strength in 3 days, 75% at 7 days, 100% at 28 days — but only if kept moist.

Remove forms after 24-48 hours (concrete is hard enough to support itself). Backfill around footings or retaining walls with graded fill, compacted in layers. For driveways, wait 7 days before light traffic, 28 days before heavy loads (trucks, RVs). Seal the surface (optional) with a penetrating sealer or acrylic coating to protect against deicing salts and moisture.