The picture above shows the process of pouring a concrete basement slab. Some people would think that it’s just poured out of the truck, self levels and there you have it, a slab of concrete. In reality this is a very tedious process that is not only time and labor extensive, but also requires a significant amount of patience as well.
For difficult to reach projects (like this basement nestled between two houses and a golf course), there is a need for a Pump Truck. When the Pump Truck is used, the concrete trucks will dump the concrete into the back of the Pump Truck instead of into the basement. The Pump Truck will then pump the concrete up through a giant z-boom and into the basement. (You can see the end of this boom in the top left corner of the picture.) What you can’t see is the guy holding the end of the boom evenly dispersing the concrete in a near level fashion.
Once the concrete is poured in, any visually uneven sections that are too high, are raked to lower sections. Then two people will work together using a large flat straightedge (metal pole with flat edges) to flatten out the concrete. This processes is known as strikeoff or screeding and is used to provide a leveling feature at the desired thickness of the slab.
The next step is the tamper tool (seen in the center right) this tool is used to push any coarse aggregate down beneath the surface of the slab. If you look closely, you can see the pattern it leaves behind from the perforated metal platform. The perforated platform allows the worker to push the coarse material down, while allowing the smooth material to surface.
Once the concrete is tampered, the workers will use the Bull Float (darbies) to smooth out the surface. The tool is seen at the top center of the picture. It looks like a giant swifter with a flat, very smooth, metal end piece. It is used to smooth out the pattern left behind the tamper tool and give the basement that nice flat floor look and feel.
The workers then have to wait for the concrete to be hard enough to walk on without sinking into, yet wet enough to finish. Depending on the weather conditions, thickness poured, type of aggregate, etc this could be minutes to hours. Once it’s ready though, they will have 1 or 2 personal hand floats and/or trowels and begin the finishing touches on the floor. Typically basements are done with a smooth finish but if this was a garage, driveway, sidewalk, porch, etc it could be finished off with spirals or a broom finish.