How To Install Basement Windows In Cinder Block Foundation

Cutting Concrete Block To Install Window

By Robert Robillard on Remodeling

Installing A Basement Egress Window In Physical Wall

We recently were asked if nosotros were interested in cutting concrete blocks to install a window. The client had an existing unmarried pane glass window that was much narrower and shorter than the opening required to install 2 new Anderson windows that they had acquired.

Concrete Wall Cutting Companies

Typically we would hire a physical company to cutting foundations for us, but that tin can become costly at a rate of $1600 a twenty-four hours. 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.

We finally settled on using a Husqvarna nine-inch cordless cut off saw. This saw runs on batteries and does not pollute the house with fumes. Click hither to read the tool review on the Husqvarna ix-inch Cut Off Saw.

Because this saw has a iii-inch depth of cut nosotros knew we would need to make these cuts from both sides of the wall.

Measuring The Windows – Layout

We were going to install the windows side past side with a 2×4 between the two for a nailer and to conform a small-scale corporeality of trim. The windows would be installed within a frame of 2×8 pressure treated framing lumber.

To determine our framing crude opening, we placed the windows on the floor, with a 1-1/ii" space betwixt the two and measured the width and length, adding 1″ to the width and ½" to the height measurement, for plumbing and shimming. Once we had this measurement the next steps were to figure out the framing measurements.

We added 6 inches on the width of the opening to accommodate two 2×8 jack studs on each side. We decided to cut the bottom of the window on a mortar articulation that would allow us to install a 7-1/4 inch header on top of the window. Adding these measurements to our rough opening measurement gave u.s. the total concrete block to cutting.

Preparing – Cutting Concrete Block To Install Window

With the total measurement figured out, we transferred this measurement to the concrete cake wall and leveled and plumbed out marks on the wall with a permanent marking. The marker does not launder off similar chalk does, and is darker and easier to see over pencil.

In one case the window was marked out on the inside we used a Makita hammer drill and drilled through holes in the physical cake at all corners. These holes were and then used on the exterior of the wall to locate our cut lines. We repeated the step above on the outside.

We then set up a water hose to our saw for a concrete block wet-cutting performance and had a wet vacuum ready to collect the slurry.

Cutting the Concrete Wall

When cutting an opening in an existing block wall, attempt to marshal it with existing mortar joints.

We used the saw to score the line and and so to brand a iii-inch deep cut on both sides. Once complete nosotros used a sledgehammer to break the concrete blocks at the scoreline.

Once you've opened up the wall, you'll have a number of partial concrete blocks that will need to be filled in with mortar or replaced.

We brought the window opening lower than needed to be able to break the opening at a mortar joint and to allow for a 7-1/iv" header to a higher place.

Repair the opening as required, adding wire mesh to the cavities to give your mortar something to hold on to, or install a force per unit area-treated "forest buck" and secure it in place with Tapcon masonry screws.

Note – we installed a 2×six pressure treated "forest buck" into one cavity and secured information technology in place with concrete screws. We were so able to boom our framing to this buck.

Fastening Framing To Physical Block CMU

We used pressure treated lumber in all areas that contact the physical. 2×8 pressure level treated lumber was used, and the first piece installed was the rough framing sill. We chiseled as needed, leveled and installed a ii×8 sill plate in the opening. The sill was then fastened to the physical block with 3-inch Tapcon concrete screws and a hammer drill.

Two vertical "jack studs" were installed on both sides of the opening to support the triple ii×6 header above. The king stud touching the physical block wall was also secured with concrete screws.

Install A Window Header

A triple ii×6 header was installed and supported by two 2×8 vertical studs. We measured and installed our middle separating stud and applied Vycor wrap to protect the framing.

Install the Basement Windows

The windows were then installed level and plumb in the rough opening and nailed off with 2-inch nails. Lastly, we taped the window flanges with 3M window flashing tape.

Insulate and Air Leak Seal Around Windows

Insulate the gap between the window frame and the rough opening by filling it with low-expanding spray foam insulation. Apply low-expansion foam that is specially formulated for windows so information technology doesn't expand excessively and warp the window frame.

Trim Out the Window

The outside of this window will receive a PVC sill and 1×four PVC casing. The interior will be framed out and boxed to extend into the room [Extension Jambs] and connect with a future 2×4 wall. Hopefully, this article gave y'all a decent understanding of how cutting concrete blocks to install a window tin be accomplished.