Things You'll Need
New frame with existing wall anchors
Drill with masonry bit
A metal door frame is commonly used in place of a wooden frame in applications subject to high traffic or abuse. In masonry walls, including brick or cinder block, the frame butts against the edge of the wall, making it fairly easy to remove and replace a metal frame without damaging the existing masonry. To maximize your chance of success with this project, take precise measurements and make sure you choose the best frame for the job.
Cut away any existing caulk from around the perimeter of the frame. Repeat this process on both the interior and exterior sides of the door opening.
Pry the frame away from the bottom of the cinder block wall using a pry bar and maul hammer. Wear safety glasses during this task to protect your eyes.
Slide your grinder into the space between the frame and the block wall. You may need a partner to help keep the frame pulled back from the wall while you work. Cut the anchors or bolts using your grinder, working your way from the bottom of the frame to the top. Repeat this process on the other side of the frame until you remove all fasteners.
Remove the frame from the opening and set it aside for disposal or recycling.
Measure the opening using your tape measure. According to the Steel Door Institute, the new frame should be 3/16 of an inch smaller than the opening on all three sides. Before ordering your frame, take special care to check the height of the header on your old frame. Standard frames often have a 2-inch header, but frames in masonry walls may have a 4-inch header to line up with block coursings. Buy a frame with a header that's the same height as your old frame so it will fit properly within the opening.
Purchase your new frame. When ordering, specify that you need existing wall anchors (EWA). This is a standard option offered by most manufacturers, and allows you to install the frame in the existing opening.
Slide the new frame into the opening. Use a pencil to mark the location of all anchor holes in the jambs. Extend the pencil through each hole and mark the cinder block walls, then remove the frame from the opening.
Use a drill with a masonry bit to predrill holes at all locations marked on the cinder block. Wear your safety glasses to protect your eyes.
Slide the door frame back into the opening. Use a hammer to drive the expansion anchors/bolts into each hole in the frame. Stop when the anchors are flush with the face of the frame.
Tighten each anchor using a hand-held screwdriver (not a drill). As you tighten the anchor, it will expand inside the cinder block. When the anchor is fully expanded, you will not be able to tighten it anymore.