Calgary Concrete Pros

How To Finish Concrete: Step-By-Step 

Step 1 - Pour the Concrete

Once pouring has begun, use a shovel or concrete come-along rake to spread the concrete along the entire slab formwork to fill the space.

Step 2 - Strike Off the Concrete 

Screeding involves dragging a flat edge over wet concrete to level it and bringing it up to a specified grade. To use a screed properly, start at one end of the freshly poured concrete and work your way toward the other end progressing slowly using a sawing and scraping motion. This back-and-forth movement pushes excess concrete further into the gaps and hollows. Make sure you avoid letting it sink into the fresh concrete to prevent large voids from being created. 

Effectively screeding your concrete will level it out, resulting in an even surface. This should be done quickly because there is a small window of time before bleed water rises to the surface.

Step 3- Float the Concrete

Sweep the darby or float across the concrete in overlapping arcs to flatten the surface, push down lumps and fill voids. It may be tempting to excessively float the concrete but doing so prevents bleed water from rising to the surface. It’s important for this bleed water to evaporate because this is excess water that is pushed up once the heavier aggregates settle at the bottom of the slab. Excess water weakens concrete slabs and increases the odds of cracking. Just a couple of passes would be ideal. 

Step 4 - Trim the Edges 

Trimming the edges of a concrete slab produces crisp edges that improve its overall appearance. Aside from that, the edge tool also creates a makeshift seal that acts like a permanent concrete formwork around the entire slab. Run the tool along the perimeter of your slab in long, sweeping strokes until the edges are smooth, solid, and straight. Use the hand float to smooth over the marks made by the edger.

Step 5 - Create Control Joints

As the concrete cures, there is a reduction in volume or shrinkage that could cause cracking. Jointing is required to eliminate unsightly random cracks; these should cut at least 25% of the way through the concrete's depth. Contraction joints or expansion joints are made with a groover or by inserting strips of plastic, wood, metal, or preformed joint material.

Step 6 - Apply a Troweled, Broom, or Stamped Finish 

At this point, if a smooth finish is desired and advantageous then consider a troweled finish. A steel trowel should only be used to smooth the surface after it's partially hardened. To achieve a smooth finish, hold the trowel almost flat and then swing the trowel in large overlapping arcs while applying pressure.

On the other hand, if the concrete is outdoor and traction is a priority, then consider a broom finish. Broom finishes create small ridges that prevent slips and falls. 

If a more decorative and textured look is desired then concrete stamps. Use this once the concrete feels slightly dry to the touch without any sand clinging to your fingers when you run it across the surface. 

Step 7 - Cure the Concrete

During curing, concrete develops its strength and durability. Curing involves the maintenance of the desired moisture level and temperature conditions. After finishing concrete, it's considered best practice to constantly hose the concrete with water to keep it moist. Moist-cured concrete can be up to 50 percent stronger compared to dry-cured concrete. Concrete can also be sealed after it has cured for at least a month to prevent liquid damage and make it easier to clean. Concrete takes an average of 7 days to cure before reaching approximately 70% of its compressive strength. 

Make sure to stay safe while working with concrete: 

• Wear waterproof gloves, long-sleeved shirts, and long pants 

• Rinse your clothing if it gets wet from fresh concrete 

• Wear high rubber boots if you need to stand in fresh concrete 

• Use waterproof pads between your hands, elbows, or knees and fresh concrete