Removing a bolt from concrete involves a lot of trial and effort in order to get the metal object to come loose. Following are a series of steps you can undertake to complete this task. These steps are designed so that if you are unsuccessful at one step, you should proceed to the next step. Once the bolt is removed, you may proceed to the last step.
Take two threaded nuts and thread them onto the bolt. Make sure they are tight together and that the edge of the top nut is flush with the upper side of the bolt. Take a pair of pliers or vice grips and just pull on the nuts in an upward direction. Perhaps you will get lucky and the bolt will come right out.
Take a long 2 by 4 and place one end on top of the bolt. Hold the other in your left hand. Now take a large framing hammer or small sledge hammer and bang on the wood right above the bolt. Do this with increasingly stronger strokes until the bolt comes loose.
Take a pipe wrench or a pair of vice grips and twist the top of the bolt to see if you can get it to come loose. Make sure that the bolt stays upright and perpendicular to the surface of the concrete.
Add a pipe to the end of your wrench and try again to twist the bolt loose. A piece of galvanized water pipe that is three or four feet long and ¾-inch in diameter is ideal. Twist slowly and try not to bend the pipe.
Cut the bolt with a reciprocating saw, hacksaw or metal chisel, if all else fails. Cut as close to the surface as possible. Then, using a metal chisel and small sledge hammer, chip away at the remainder of the bolt until there is nothing left above the surface of the concrete. Chipping away some of the concrete is inevitable, but try and keep the hole as small as possible. Patch the hole with a concrete patch, which is readily available at almost any hardware store or building-supply outlet.
Things You Will Need
- Vise grips
- 2 nuts that fit the threads on the bolt
- Pipe wrench
- Small short-handled mallet or sledge hammer
- Metal chisel ½-inch wide
- Reciprocating saw
- Safety glasses
- Galvanized water pipe (three to four feet long and ¾-inch in diameter)
- When you are attempting to twist the bolt, be sure the bolt remains perpendicular to the surface of the concrete and that it does not bend.
- Have someone help you hold the wooden board during Step 2.
- Don't forget to wear safety glasses, especially when cutting or chiseling on the bolt.