Concrete Contractor Woodland Hills CA needs a firm, flat sub-surface on which to be placed; much of the concrete’s strength depends upon it. Often washed stone or gravel is used to level out parts of the area to be covered with concrete. Small washed stones often referred to as pea-gravel are easy to level with a rake and provide a suitable sub-surface. The level stones also allow your contractor a uniform base from which he can accurately estimate how much concrete will be needed.
Once the sub-surface is prepared. The next step is to form the perimeter of the project. Forms can be made from any material, but usually wood and metal are most common. Sometimes contractors use masonite, or even plastic for curvy sections. Many residential concrete driveways are 4 inches thick; however driveway thickness can vary up to 6 inches. For a 4 inch thick concrete driveway, usually a wooden 2 inch by 4 inch board is used on its side and placed around the perimeter of the project. Once the form boards are in place, reinforcing wire mesh or reinforcing bars (re-bar) are laid within the project to help either reinforce the concrete or keep it from separating.
Concrete is ordered and delivered from a local batching plant. Concrete is often ordered at pounds per square inch (psi) rating of around 4000psi. This usually means about 6 bags of portland cement to every yard of concrete. When the concrete arrives it usually requires that water be added to achieve the correct consistency or slump.
The concrete is placed between the forms. A screed is used to level the concrete. A screed is a straight board or piece of aluminum in the shape of a 2 by 4 board that the contractor uses to level the top of the concrete. Contractors will now begin the finishing process by floating the surface. The tools can be hand floats up to as big as a finishing tool called a bull float. Floats are used to help level and fatten the concrete even further. The aggregate or stones in the concrete are pushed down into the concrete giving the slab a smooth finish. At this time the contractor will likely begin other finishing steps including edging the concrete with an edging tool or hand cutting the slab.
After a brief initial drying period, the concrete is ready for final finishing. Drying time can be as little as a few minutes to up to an hour. In places where the concrete will be exposed to the elements, the concrete requires an anti-slip texture to be applied. Often these textures can either be a variation of a magnesium float finish or a broom can be drug across the surface.
The concrete slab should be saw cut for stress relief if it wasn’t already hand cut during the finishing process. The saw cutting of the slab weakens the concrete where it has been cut so that when the concrete cracks from various pressures it will hopefully crack where it weakest; in the saw cut. The idea is that it is better to have cracks that are straight inside your saw cuts where you can’t see them then to have cracks running rampant throughout the slab.
Curing and Sealing
The concrete will need to cure before it can be fully utilized. During this curing process, it will be necessary to apply a curing/sealing product to help the concrete cure slowly and evenly. A curing product will slow the evaporation of water from the concrete helping eliminate potential problems such as cracking. The curing process usually last between 1-2 months; longer if the temperature is cool. The concrete should be cured well enough however for a vehicle to be parked on it in as few as 7-14 days with 14 days being the safer amount of time.