If you are a handyman or do-it-yourself type of person there may come a time when it is necessary to cut a hole in a brick wall or foundation. At one time this project would entail using a chisel and hammer to break and chip the brick and mortar from the proposed area. Today, however, there are masonry blades to fit a skill saw which makes it much easier to cut the proposed hole. This article will take you step-by-step through the planning and cutting stage of penetrating through a brick wall or foundation.



Planning and Marking the Cut-out


The photos accompanying this article illustrate the procedure for cutting a hole in a brick foundation. The owner of this home needed more ventilation beneath his house to help rid excess moisture causing mold and mildew to form on the sub flooring and floor joists. This is a single trace of brick to be removed so a vent may be installed. The same procedure can be followed for larger openings such as for making an extra door or window opening. For these openings it is important to start at the top of the proposed opening and to insert a header as soon as possible to hold up the remaining brick above the opening. Without such a header the brick and mortar above the proposed opening may crack or collapse without anything to support it.

It is important to first find out what is behind the brick you are planning to cut away. In this case it was critical to not cut a hole in front of the concrete pillars supporting the floor. These pillars would block the flow of fresh air and render the vents useless. The possibility of plumbing and electrical wiring being in the cutting area should be taken into consideration before attempting to make a cut. For this job it was necessary to look under the house to ascertain no such problems would arise.

For wider openings you may wish to know what studs to cut between and if a header is needed to support the wall. You may even decide to cut the inside wall first to make sure of obstructions before cutting the outer brick wall. Once the dimensions are decided it is time to mark the brick for cutting. A piece of chalk is useful to mark the desired cutting lines. Try to avoid leaving small brick pieces on either side of the hole. It may be helpful to move the lines a little left or right to help avoid this occurrence. When you are satisfied with the dimensions you may now chalk the lines for cutting.

                                                      Cutting the Hole with the Masonry Saw


Although the masonry blade is not sharp, it can still cause injury to exposed skin so be very careful as always when using any power tool.  Be sure to use a quality pair of safety glasses and gloves for the hands.  A dust mask of some sort is also recommended to keep from inhaling the mortar and brick dust being expelled from the cut.  Because it is hard to keep the saw perfectly aligned with the mark it is recommended you cut slightly inside the lines to avoid damaging the remaining brick.  It is easier to trim any brick away after the final cut if needed. 

A plunge cut is used to start the hole.  Set the saw to its deepest cutting level even though it may not cut completely through the brick.  Start away from the corners and slowly lower the blade into the cut.  A firm grip is needed to keep the saw from jerking when it contacts the brick.  The saw will try to go the direction of the blade rotation but not enough to make it hard to hold steady.  You will quickly learn to maintain the saw enough to cut easily and quickly.  Do not cut past the marked corners as these will be finished by hand.  If possible, make your upper and lower cuts in the mortar as this material is easier to cut than the brick.

Trimming and Installing the Frame


Once the brick has been cut to your satisfaction it is time to remove the debris from the area. If the saw blade did not cut completely through the brick you must finish the cut by hand. Here is where using a hammer drill will speed the process and help avoid wielding a chisel more than necessary. Using a masonry bit, drill a series of holes along the sides of the cut and along the top and bottom too. The more holes you drill the less you will have to chisel. The safety glasses are worn during the entire process including drilling and chiseling. A good set of masonry chisels makes the difference is how easy it is to complete the job. Like using the saw, you soon learn how to remove the excess brick with the chisel.

Once you have completed the hole it is time to frame the opening. In this example pressure treated 2x 4’s are used. The top and bottom pieces can be cut slightly shorter than needed but the sides should be cut tight enough to give support to the brick above the hole. Concrete screws are used to attach the frame firmly to the sides of the hole. The hole is now ready for installation of the vent or whatever purpose needed. Once you have completed your project you will have gained valuable experience for future construction endeavors involving cutting and expanding openings in brick or block wall. As always, be extremely careful both in planning and cutting the hole. Good luck with your project!