Concrete blocks are often used to build basement and foundation walls in the home, though they can also be used in other locations as well. These blocks are durable and easy to install, but can be difficult to modify or remove. To install a door in a concrete block wall, you'll need to first create an opening for the door. The task of installing the door itself is relatively simple, while creating an opening in the wall is often a bit more challenging.
Mark the opening size for the door on both sides of the wall. The opening should be two inches wider than the door frame, and about an inch taller in height. Add another set of marks across the top of the frame to represent a steel lintel that will support the load above the door. The lintel should be centred over the door, and should be 6 inches high. It should also extend 6 inches past the door frame on either side.
Score the lines for your opening with a circular saw. You'll need a masonry saw blade to make these cuts. Repeat this process on the other side of the wall, scoring about 2 inches through the concrete on either side.
Use a sledge hammer to break through the concrete inside the scribed lines. When you get near the edges of the opening, you may wish to switch to a masonry chisel and hammer to prevent accidental damage to the surrounding walls.
Re-form the blocks as needed. If you've cut into the hollow part of any blocks, wedge a piece of 2x4 lumber into the end of each cavity and fill the block with mortar. This will create smooth, solid edges that will be helpful when installing the door.
Install the steel lintel above the door. Wedge the beam into the opening, then pack any gaps with masonry mortar. The beam will distribute the weight of the wall's load to either side of the door opening.
Choose your frame. Hollow metal frames are typically used in masonry walls. The frame should be sized to butt against the block on either side, and should have a jamb depth equal to the wall thickness. Purchase a frame designed for installation in existing masonry walls. The frame will have "dimples" punched into the jambs to accomodate masonry anchors.
Measure the height of the dimples on either jamb. Transfer these measurements to the centre of the wall on either side of the opening. Pre-drill holes at these locations to accommodate the anchors for the frames.
Center the frame within the opening and insert the expansion bolts for your existing wall anchors (EWA anchors) into the dimples on the frame. Hammer the anchors into the dimpled sections of the frame until the head of the anchor is flush with the frame. These anchors are designed to expand into the masonry after they are installed to hold the frame in place.
Fasten the hinges to the door, then install the door into the opening. Tighten or shim the hinges as needed to plumb the door. When the door is properly installed and levelled, there should be equal spacing between the door and jamb along the entire length of the opening.
Choose a lockset or handle and install it according to the manufacturer's instructions. Add trim or casing around the door as desired, or caulk between the frame and the concrete block to complete the project.
Many cities and counties require building permits for projects like these. Consult your local permit office (see Resources) to determine whether you'll need a permit. You may also be required to consult a structural engineer before cutting into a concrete wall.