When converting a basement into a living area or a bedroom for your children, safety is a primary consideration. Today's building codes specify that a finished basement must have an emergency egress—an egress window or door large enough to allow people to easily exit the space, and for rescue crews to gain access in case of fire or other emergency. Besides feeling more secure, you’ll also benefit from natural light and ventilation, adding to the comfort and value of your basement man-cave or extra bedrooms.
Adding an egress window usually means cutting a large enough hole in your concrete basement wall. If your basement has solid concrete or concrete block walls, the job will require the services of a skilled concrete cutter, mason or basement remodeling specialist. It’s a noisy, messy job, but the process is relatively straightforward for a skilled professional.
For some yards, you can install egress windows above grade. If your foundation walls barely appear above the soil line, then you will have to excavate down and provide a window well. Your concrete cutting contractor may be able to assist with this excavation.
Be sure to check your local building codes for the size of a window well and should allow a person to easily climb out of the window and exit the house. In case of a deep well, a ladder must be fixed to the well so that a person can safely climb out.
If your egress window requires a window well, be sure to have all buried utilities marked so that you don't cut any electrical, gas, cable, water, or sewer lines.
According to the most current residential building codes, if your basement retreat includes one or more “sleeping rooms,” such as a dedicated spare bedroom, each of those rooms must have an egress window. In addition, a single egress window must be furnished for “common-use” areas, such as a TV room, game room, or home office. Occasional-use spaces, such as bathrooms, laundry rooms, and utility areas, usually don’t need emergency egress.
Be sure to check your local code which will define the opening of a basement egress window and the height, and the smallest opening an average adult male can reasonably crawl through.
When shopping for an egress window, make sure to calculate size correctly. Do the math, most of the time a 20-inch-wide window actually needs to be 41 inches tall to comply with the minimum square-foot requirement for an egress window. Similarly, a 24-inch-tall window must be at least 34.2 inches wide.
Building a window well
Installing a code-compliant egress window with its sill only 44 inches from the finished floor likely means an excavation outside your foundation walls to create a window well. By code, the total “clear” floor area inside of the well must be at least 9 sq. ft, with at least a 3-foot area between the window and the far edge of the well opening.
If the window well is more than 44 inches deep, it must have a permanently attached ladder or steps to enable safe egress. The ladder or steps can project into the well no more than 6 inches without having to extend the code-required clear area of the well. As such, most ladders are welded to the metal shell that encloses the well.
For the safety of your family when you are gardening or playing outside, building codes also allow a metal grate, typically hinged, to be placed across the window well opening to protect pets and people from falling in. Still, you must be able to remove or open the grate from inside or outside the window well without special tools in the event of an emergency.
To facilitate drainage of the well, the construction may include installation of a perforated pipe covered over with washed gravel to carry excess water away from the well, window, and foundation wall.
Because a window well is a prominent feature when viewed from inside the basement room, it’s a good idea to incorporate some simple landscaping features, such as potted plants. Make sure that any design features won’t interfere with safe egress.
Hiring a licensed contractor to cut your basement wall, build a window well, and install a window will cost $2,500 to $5,000, depending on the complexity of the project and the depth of the well. Adding a grate and providing drainage adds another $500-$800.
If you plan to tackle the installation of an egress window as a DIY project, you’ll save money. Cutting through concrete walls is a major task. You may be better off to hire this out. Just make sure you have planned the opening correctly. A concrete cutter is not responsible for engineering your egress window. Here's a video on how a professional concrete cutter makes it look easy. https://www.youtube.com/watch?v=Y1pGCrQaRuY
Before you begin any DIY work, be sure to get advice of a structural engineer to examine your walls and advise you about any concerns, such as installing a header over your window to accept the weight of floor joists and a load-bearing wall above. Expect to pay $150 for a consultation.