Once the window was marked out on the inside we used a Makita hammer drill and drilled through holes in the concrete block at all corners. The marker does not wash off like chalk does, and is darker and easier to see over pencil. With the total measurement figured out, we transferred this measurement to the concrete block wall and leveled and plumbed out marks on the wall with a permanent marker. Preparing – Cutting Concrete Block To Install Window Adding these measurements to our rough opening measurement gave us the total concrete block to cut. We decided to cut the bottom of the window on a mortar joint that would allow us to install a 7-1/4 inch header on top of the window. We added 6 inches on the width of the opening to accommodate two 2×8 jack studs on each side. Once we had this measurement the next steps were to figure out the framing measurements. To determine our framing rough opening, we placed the windows on the floor, with a 1-1/2” space between the two and measured the width and length, adding 1″ to the width and ½” to the height measurement, for plumbing and shimming. The windows would be installed within a frame of 2×8 pressure treated framing lumber. We were going to install the windows side by side with a 2×4 between the two for a nailer and to accommodate a small amount of trim. Click here to read the tool review on the Husqvarna 9-inch Cut Off Saw.īecause this saw has a 3-inch depth of cut we knew we would need to make these cuts from both sides of the wall.

This saw runs on batteries and does not pollute the house with fumes.

We finally settled on using a Husqvarna 9-inch cordless cut off saw. Using a gas cut off saw was also an option, but this house is occupied and we thought it best to avoid the exhaust from the engine. Typically we would hire a concrete company to cut foundations for us, but that can get costly at a rate of $1600 a day. The client had an existing single pane glass window that was much narrower and shorter than the opening required to install two new Anderson windows that they had acquired. We recently were asked if we were interested in cutting concrete blocks to install a window. Installing A Basement Egress Window In Concrete Wall

Window on cmu detail