Anchor bolts are used to secure objects to concrete. One common use is in the walls of a home where the bolts are used to secure the stud bottoms to the foundation. These anchor bolts are usually secured in the concrete by means of an anchor, typically made out of lead. To remove an anchor bolt from concrete, all that is needed is to unscrew the bolt from the anchor. Occasionally you will run into problems with stubborn anchors that don't want to unscrew; in that case, there are other solutions you can try.
Determine the size of the anchor bolt head. Many hex bolts will have the size imprinted on the top. Select a socket of the same size and attach it to your socket wrench.
Remove the anchor bolt from the concrete by turning the bolt counterclockwise with the socket. If the bolt is rusted in place, spray it with a penetrating lubricant and allow the lubricant to soak in according to manufacturer's instructions before removing.
Use a bolt extractor on a stubborn bolt. Attach the extractor to the end of a drill and place this over the bolt. Drill into the concrete until you reach the base of the bolt. Remove the bolt with a pair of pliers.
Insert the awl into the anchor hole. Give the awl a few sharp taps with the hammer until it cuts through the anchor. Remove the anchor parts with needle-nose pliers.
Cut off the bolt head, when none of the other methods work. Attach a metal cutting blade to a rotary tool. Cut the head off the bolt. Sand down the area surrounding the bolt to about one inch outward with a concrete sanding blade. Sand or cut down the top of the bolt so that it is below the surface of the concrete. Clear up any debris with a shop vac. Fill in the hole with a concrete patching solution.
If the anchor bolt is surrounded by an anchor plate, this needs to be removed before you can tackle the bolt. Use a pry bar to pull the plate away from the bolt.
Tips and warnings
- If the anchor bolt is surrounded by an anchor plate, this needs to be removed before you can tackle the bolt. Use a pry bar to pull the plate away from the bolt.