How to Cut a Concrete Block Wall
Concrete block, also known as cinder block, is a common building material. It can be found in garages and certain types of residential architecture. Adding windows and doors to concrete block walls requires cutting the block. This requires a specialized blade for your circular saw. You will also need safety glasses, a dust mask and hearing protection. Set up a fan to clear the dust and use a shop vac to keep the dust clear from the cut.
Mark the area you wish to cut out of the wallt. Mark the corners of the area with a ten inch rotary mason's bit. Drill completely through the block and out the other side to mark the corners. Keep the drill level. With a marker, connect the corner holes on the opposite side of the wall to mark the outline of the cut out area.
Install an abrasive disk blade in your circular saw. Start by making the top horizontal cut. Begin at one corner. Set the depth of the blade as deep as it will go. Rest the front of the saw base against the wall and visually line up the blade with the outline on the wall. Start the blade and let it reach full rpms.
Tip the saw so the blade comes in contact with the wall. Apply steady pressure to maintain the contact. Do not force the blade. The friction will wear the abrasive disk down too quickly and the saw will lock up. Continue cutting along the line, replacing the disk as it wears down. Follow the saw with the hose of a shop vac to collect the bulk of the dust and keep the field clear so you can see the outline.
Cut all sides of the cut-out on the first side of the wall. Move to the other side of the wall and continue cutting. Once all sides of the outline are cut cleanly through, use a sledge hammer to knock the blocks out of the wall.
Chisel any remaining rough edges smooth using a three-pound hammer and a brick chisel.