How to Break Concrete for the Plumbing for a Sink

Lay out a trench with parallel lines 6 inches apart with the chalk line. Stretch the line between two points on the slab, lift the string and let it snap onto the slab to create a chalk line. The bright pink or green chalk colors help you see the line through the dust and debris as you are working.

Spray the chalk lines with hairspray. The hairspray prevents the lines from disappearing as they are walked on and the dust is swept or kicked away.

Install the straight, pointed bit in the jackhammer. Start at one end of the trench and place the bit against the concrete centered between the two chalk lines. Hold the jackhammer handles with both hands, keep the jackhammer vertical and squeeze the trigger. The bit will work itself into the concrete. Allow the bit to penetrate about 1 inch, pull it out and move it 2 inches away. Start out vertical until the bit penetrates, then slope the jackhammer slightly towards the initial hole. Work in a small square and continue until you have made a hole 4 inches square all the way through the concrete slab.

Remove the straight bit and install the wide chisel bit. The wide chisel bit removes larger pieces of concrete once a hole has been made. It is possible to make a reasonably straight line with the wide chisel.

Place the bit against the chalk line and hold the jackhammer vertical. Squeeze the trigger and let the bit penetrate the concrete about an inch. Repeat on the other line across from the first.

Move the bit between the chalk lines about 3 inches from the hole. Start the jackhammer and after the bit begins to penetrate, angle the jackhammer towards the hole and continue until the piece breaks off. Repeat this and the previous step until the trench is complete.

Straighten the sides of the trench with the wide chisel bit by placing the bit against protruding concrete to hammer it off.