Break up Concrete

Those who have concrete floors, driveways, or sidewalks around their property, may need to break up concrete to repair underground plumbing or other utilities. These steps will help you learn the basics for this daunting job.

Steps

 * 1)  Determine if and where you will need to break the concrete.  If you are looking for a broken water or drain line, and you can locate the general area you suspect the problem to be in, you can save a lot of work and expense.  Here are some things to look for:
 * 2) *For plumbing problems, try to determine the location and depth of the underground pipes. Look for a valve exterior hose bibb; or on a waste line, a cleanout to indicate the location of pipes.
 * 3) *For water problems, look for areas where water is either bubbling up through cracks in the concrete, or seeping out around the edges of the slab.
 * 4) *For electrical lines, you may find you have to locate the conduit outside the slab area and dig up a length of it to determine where the rest of it runs.
 * 5) *For other types of repairs, or for installing new utilities that require excavating a ditch through an area paved with concrete, you may have to guess or research construction plans to determine where to begin.
 * 6)  [[Image:Breaker3_580.jpg|thumb|A 40 pound pneumatic breaking hammer used for removing concrete from fence posts.]]Find out how thick the concrete is.  Dig at the edge of the slab and look at the side of the concrete.  Some slabs have thickened edges, monolithic foundations, or abutting structures that prevent you from doing this, so you may need to hammer drill a hole through the slab where you intend to break it to test its thickness.  The main focus of this article is breaking up typical floor slabs, about 4 inches thick.  For thicker concrete, an electric chipping hammer is not appropriate, so renting an electric breaker in the 60 pound range, or even a pneumatic jackhammer is your best bet.
 * 7)  [[Image:Gustav_440_757.jpg|thumb|Hammer drill on left, rotary hammer on right]]Gather the tools you will need to do the project.  For small break-outs, a sledge hammer may suffice, particularly if the concrete is thinner than 4 inches, and it is not reinforced.  This article will deal with breaking out concrete where power equipment is required.  In this case, you will need a demolition saw or circular saw with a dry cut concrete (masonry) blade, a chipping hammer, and a shovel.  See Things You'll Need, below for a complete list.
 * 8)  Mark the location of the portion of the slab you intend to remove.  Measuring distances from the edges of the slab will allow you to make a regularly shaped hole, which will make the finished repair look neater and less noticeable.  Use a pencil and straightedge or a chalk line to make an easily visible mark around the planned hole.
 * 9)  [[Image:Concrete1_325.jpg|thumb|Concrete is saw cut and ready to begin breaking]]Saw cut the line as deeply as possible with a demolition saw, a circular saw, or a grinder with a dry cut diamond blade.  This will give a clean edge when the demolition is completed.  If you are searching for a broken water pipe (as in the photos) you may have to enlarge the hole after the initial break is done.
 * 10)  [[Image:Concrete3_748.jpg|thumb|Beginning to break at the edge of the saw cut]][[Image:Concrete5_505.jpg|thumb|Continuing to break along the edge of the cut]]Using a breaking chisel in a rotary hammer (or heavy duty hammer drill), begin chipping the concrete.  Break the edges along the saw cut first, leaning the point of the chisel towards the line, so the edge cracks loose without breaking the side which is to remain.  Use care so the adjoining concrete does not spall or chip.
 * 11)  [[Image:Concrete7_11.jpg|thumb|Continue breaking your hole larger and larger.]]Work the bit around an area enlarging the hole you have begun, and going deeper with each pass, until you have penetrated the slab.  This is the hardest part of the job, since the pieces you break off cannot come free until there is a space for them to drop into.  Often, completely broken shards of concrete will remain wedged tightly until all the adjacent concrete is broken.
 * 12)  [[Image:Concrete9_333.jpg|thumb|Break away the largest sections possible to save time and work]]From the edge of your first penetration, work back, chipping into the solid concrete an inch or so from where the concrete is cracked, so that the new piece you are breaking can come loose as it breaks free.
 * 13)  Keep your chisel point slanted toward the beginning hole while you work around, so it doesn't try to penetrate straight down without breaking a section of concrete free.  If it is allowed to go too deep, the bit will become lodged in its hole and will be difficult to remove.
 * 14)  [[Image:Concrete11_164.jpg|thumb|Using a second chipping hammer to loosen a stuck bit]]Remove bits that have become lodged (or stuck), by using another breaking bit to break the concrete away from the stuck bit, chipping parallel to the original hole.  If you have a spare [hammer drill, you can simply leave the first bit in its drill and proceed, as in the photo. If not, you will have to remove the stuck bit and put a different one in the drill to do this step.
 * 15)  Break the largest pieces of concrete you can as the hole becomes large enough for them to break free.  There is no reason to chip gradually at the very edge if 2-, 3- or even 4- pound pieces can be broken free.  This will save time and making removal of the material less tedious.
 * 16)  [[Image:Concrete16_839.jpg|thumb|Removing broken pieces of concrete from the hole]]Remove the broken chunks and bits of concrete from the hole as it becomes larger, so subsequent pieces have plenty of room to drop in without becoming wedged.  This will also make it easier to spot pipes, electrical wires, or reinforcing bars you may encounter as you enlarge the hole.
 * 17)  [[Image:Concrete17_565.jpg|thumb|The hole is broken out, but large pieces remain to be chipped off for a clean, uniform patch.]]Use the chipping hammer to chip the edges of the hole when you are finished breaking it out so you have fairly vertical edges.  This will assure the repair will be full thickness, decreasing the chance of the concrete patch cracking.
 * 18)  [[Image:Concrete22_987.jpg|thumb|The slab settled here, causing this pipe to crack where it was embedded in the adjacent wall.]]Watch for evidence of the problem you are trying to solve as you make your hole in the concrete.  For water leaks, especially large ones, once you have created the initial penetration, you should immediately see signs of water or at least very wet soil.  If you can find the actual pipe, it will ensure you have broken through the concrete at the right location.
 * 19)  [[Image:Concrete10_657.jpg|thumb|Use care when this close to a PVC or other fragile pipe]]Once the pipe or other utility you are working on is located, you may have to break away concrete along the path of the pipe until you locate the damaged section.  Be careful to avoid hitting cast iron or PVC pipes with the breaking bit, as these are brittle and can easily sustain further damage.
 * 20)  [[Image:Concrete21_866.jpg|thumb|Breaking the vertical concrete wall so repair can be completed]]Break vertical concrete (as in the wall in the photo) much the same way you began the break in the slab.  It is easier if you know the exact location where the repair needs to be made. Take care to protect adjacent surfaces while you work.
 * 21)  Remove all the debris from your hole and make your repairs, then grade and compact the fill material and pour new concrete in the hole to patch it.  For pipes, such as those in the photos, some builder's sand can be layered above them to cushion them from movement in the concrete after it has hardened, making the need for future repairs less likely.

Tips

 * [[Image:Breaker1_411.jpg|thumb|This is a 60 pound electric breaker rented for the job.]]Look for specialized concrete breaking tools and accessories at tool and equipment rental outlets if you will only need them for a single job, as these machines are very expensive.
 * [[Image:Gustav_442_360.jpg|thumb|Make sure the function selector of the rotary hammer is on hammer, not drill, as shown here.]]Use the largest hammer drill or rotary hammer practical for your job. These are expensive tools, so if you only need them for one job, renting is more economical than purchasing them.
 * Use smaller tools for close work, near pipes and other fragile components of the structure.
 * For an area larger than 15-20 square feet, renting a jackhammer or contracting the job out to a qualified demolition person may be easier.
 * Avoid damaging reinforcing bars and mats if possible, so the patch will have similar strength to the adjacent concrete.

Warnings

 * [[Image:Gustav_430_393.jpg|thumb|Those feet are very close to the breaking bit, so heavy boots will offer some protection]]Wear heavy boots, gloves, and safety glasses while performing this work.
 * Wear a dust mask or respirator when dry cutting concrete and, if possible, use a wet cut system. Concrete contains silica and can harm your respiratory system. Older concrete can also contain asbestos; test before you start working if there is any doubt as to its makeup.
 * Be careful when breaking concrete that may contain live electrical wiring or compressed gas lines. A call to your local utilities can save your life and a lot of money. Look in the yellow pages.
 * Read all manufacturer information on tools and follow safety rules. Do not use a piece of equipment until you fully understand how to operate it safely.
 * Broken concrete can have very sharp edges. Wear gloves.
 * Rotary hammers have a lot of torque. Be sure to use any auxiliary handles that it is equipped with.

Things You'll Need

 * [[Image:Concrete25_232.jpg|thumb|Some of the tools we need, including breaking bits, diamond cutoff wheel, and chipping hammer]]Breaking hammer, hammer drill, or rotary hammer
 * Power cord
 * Sledge hammer (optional)
 * Safety equipment

Related Tips and Steps

 * How to Build a Concrete Driveway
 * How to Order Ready Mix Concrete
 * How to Repair a Concrete Floor