People who have concrete floor and driveways at their homes or concrete sidewalk around it, may actually need to break up the concrete for underground plumbing, utilities repairing, or maintenance. This can be a daunting job, but here are a few basic steps that will prove to be helpful in this regard.
1.The first step is to determine the exact position where the concrete needs to be broken. Locating the exact area of the problem can save a considerable amount of time and money, and complete the job with greater efficiency.
- If you are looking for plumbing related problems, locating the area and the depth of the pipes running underground is important. Exterior hose valves or clean outs are pretty helpful for identifying the location and the depth of those pipes
- For water problems, try to locate areas where water is bubbling up through a crack in the surface of the concrete, or is seeping out from the edges
- For electrical faults, before you start digging the concrete, you need to locate the conduit outside it, and then dig up a certain length for finding where the rest of it is running to
- For installation of new utilities or other repairs that require excavating an area of the concrete cover, it is wiser to consult the construction plan and then come out with a design and place to start digging
2. Once you know where you will be digging the concrete, now it is time to determine the thickness of the slab. You can dig the ground at the edge of the concrete cover and take a look at the side of the slab for a more or less precise idea. But some concrete flooring has thicker edges, while others may come with abutting structures and a monolithic foundation that prevent digging. So, it is a good idea to hammer a drill at the place one needs to dig and have an exact idea of the actual thickness or the constructional structure of the slab. Electric clipping hammers are suitable for breaking up concrete slabs around 4 inches thick, but for thicker slabs around or more than 60lb; electric breakers or pneumatic jackhammers would be a better choice.
3.Once the research and homework is done, it’s time to gather the tools for the project. If the concrete is less than 4 inches thick or it is a small project, a sledge hammer is sufficient. But in many cases, power equipment like a demolition saw, a circular saw with dry cut masonry blades, and a chipping hammer may be needed.
4. Mark the digging area clearly, so that you can dig it in a regular shape, and make the finished job look neat and also less evident. Once the area is marked, then saw cut the line as deep as possible. A demolition saw, a circular saw, or even a grinder with a dry cut diamond blade can be used for the purpose.
5.For heavy hammer drilling, you need a rotary hammer or a breaking chisel to chip the concrete. First, break along the edges of the saw line, with the point of the chisel leaning towards the line. This will loosen the edge crack, but will not break the sides. Care should be taken not to chip or spall the adjoining concrete. You need to work around the area to enlarge it, while digging deeper, until the slab is fully penetrated.Until you create a space for the broken concrete pieces to drop in, they won’t be able to come free.
6. While digging a concrete slab, the point of the chisel should always be slanted towards the initial hole, so that it penetratesin the right direction, without breaking any concrete. If one penetrates straight too deep then that piece will be lodged in as a whole, and will not also be easy to remove. By chipping in parallel to the original hole, concrete bits that have lodged can be removed.
7.Try to break out the largest piece while digging, so that the hole becomes large enough. While working on the edge, chipping small pieces is nothing but a waste of time and energy. As the hole grows bigger, simultaneously remove the broken pieces, so that, there is enough space for the subsequent pieces to drop in without getting wedged. This will also help you to dig the spot pipes, reinforcing bars, or electrical wires,as the penetration continues.
8. Once the breaking is complete, use a chipping hammer for chipping the edges. This will fully thicken the repair, and will further prevent cracks from appearing once the patching is done.
9. Once the pipe is located,the digging needs to be done, along the length of the pipe to reach the actual damaged section. It is important not to further damage the pipe, while breaking and digging the concrete. Once the actual location of the damage is identified, breaking vertical concrete chips might be easier, but the adjacent surface must be protected, too.
10. Once the fault is rectified, the debris should be removed,before the hole is patched with graded and compacted fill material and new concrete. One can also use a sand layer to prevent the pipes from being damaged by the movement of the hardening concrete.
Here are a few more tips that you might find useful.
While working close to the pipes or other fragile equipment, it’s a good idea to use smaller tools. If you need to work on an area that is larger than 15-20 square feet, renting a jack hammer or a qualified demolition professional would be wiser.
Large hammer drills or rotary hammers, which are the best equipment for such jobs, are quite expensive. If they are required only for a single project, then renting them can be a better option than buying.
When digging a concrete slab also see to it that the reinforcement bars are not damaged, so that the patch and the original slab will be of the same strength.