Measure the area of the concrete slab you need to remove. Determine the thickness of the slab. Ascertain this by digging near one of the edges if the figure is not readily available. Determine the type of concrete slab. For example, a reinforced concrete slab with rebar will require more time or heavier equipment than an un-reinforced slab.
Factor in the equipment used for the concrete removal. Methods for removal include breaking the concrete by hand with a sledgehammer or jackhammer, cutting it with special concrete cutters or breaking it up with heavy equipment such as a backhoe. Each method will increase or decrease the time needed to complete the project. Labor-intensive methods, like the sledgehammer, will take longer than using a backhoe, for example.
Establish a baseline measurement for the different removal methods. Contact an experienced contractor for the most accurate estimate. For example, according to the Goldenseal construction estimating software, an unskilled laborer with a jackhammer can break up to 8 cubic feet of un-reinforced concrete per hour. Each contractor may have a slightly different estimate. Contact at least two and calculate the average between their responses.
Calculate the amount of time it will take to remove the debris from the site. Regardless of the removal method chosen, you must also consider the time involved with the removal of the concrete from the site. Removal includes transporting the debris from the original location to the truck or removal vehicle that will transport the debris to the dumping area. The type of equipment used will also affect the removal loading time. A backhoe may be able to load the vehicle with its scoop, for example, which would be much faster than carrying the debris by hand.
Use the information obtained in the previous step to estimate the total concrete removal time.