Core drilling or any type of concrete cutting is not as easy as you might expect, which is why it's best left to a professional contractor. You might assume you can simply rent a few tools and cut through your home's basement wall or through the garage floor for new plumbing pipes, but chances are you might simply make a mess of the material and even ruin the tools. Note why this is and why this job is almost always best left to a professional contractor.
Thick concrete is often x-rayed by a professional contractor before it's cut. This is because the material may contain rebar or another such piece that was installed during pouring, to give the concrete strength and durability. Some concrete might also have certain tension cables underneath the surface. Cutting into these can damage your tools and make a mess of the concrete itself, as it may begin to chip or crack once you cut away this supportive material. If you're not sure if concrete was poured with any such supporting material, have a contractor handle the cutting so he or she can determine if an x-ray is in order and what tools to use to cut through rebar, cable, and the like.
2. Blind holes
Blind holes refers to drilling a material but not all the way through, and this can often be needed for concrete drilling or cutting. You may only need a certain depth or thickness cut in order to reach pipes, conduit, and the like, but blind holes can be very difficult to drill. You need the right drill bit to cut through the material and then need to know how to remove the core or part that was cut without damaging the surrounding concrete, or allowing it to crack. A professional can know the right tools for pulling out the core or area cut, or if it needs to be chipped and pulled out, without damaging the integrity of the cut itself.
3. Size of hole
Cutting the right size of hole when core drilling can be difficult, as you don't want to cut any more concrete than you need so that pipes, conduit, and other materials fill fit snugly. A contractor will usually know how to cut a hole a slight bit smaller than needed and then actually sand it down to the right size. This can be a difficult process for those without experience in actually cutting concrete and then sanding it without compromising its strength, so it's often best left to a professional.