Need-to-know reno info about basement windows

Are you thinking about renovating your basement? Before you start, you should be aware of all of Alberta’s safety code requirements. You will require a building permit if your alterations are more extensive than cosmetic upgrades. A development permit may be required if your proposed renovations do not meet land use bylaw requirements.

For this month’s article, I’m going to focus on window requirements. There have recently been building code changes to basement window wells. A window well is a space maintained partially or fully below the adjacent soil for a window — also known as below grade.

Basement windows can come in many shapes and sizes. If you are developing a recreation room, games room or office, the size of the window is not a matter of building code concern. However, if you decide to develop a bedroom, the size of the window is very important.

The Alberta Building Code requires that bedroom windows have at least 0.35 m2 (3.8. sq. ft.) of clear opening that a person could crawl through, with no dimension less than 380 mm (15 in.). This requirement ensures that there is an alternative way to escape in case of fire or emergency.

Where basement windows are located partially or fully below grade, a window well is also required. These requirements have been in place for many years. In the 2014 Alberta Building Code, which became mandatory last November, the clearance in front of bedroom windows increased from 550 mm to 760 mm. This requires a larger window well. The clearance also applies to any obstructions around the window, like overhead hazards that prevent a safe exit from the bedroom.

Window wells serve a number of purposes. They prevent soil from sitting directly against the window; they help prevent moisture like rain or snow from entering the basement and they provide drainage of standing water. These things help to protect your foundation and prevent damage. For windows located in bedrooms, they also provide a transition between the interior and exterior of the home that can aid in escape.

If you have ever tried to navigate through a basement window, you will likely understand the benefit of a larger window well. Although windows are not typically used for escape, the ability to exit in an emergency is very important. With basement windows typically positioned at least 1.2 m (four ft.) above the ground, the task is that much more difficult. Once you wiggle through the small opening, you are still confined by the window well itself. Increasing the size of the window well increases manoeuvrability to allow for a quicker escape. In a fire, these extra seconds can be invaluable.

On occasion, people will want to install basement windows closer to the basement floor level than is typical. Although this is possible and helpful for escape, you may not be aware of why these windows are usually located where they are. Based on the weather we experience, the Alberta Building Code lists the frost depth for Calgary at 1.2 m (four ft.). This means that you need at least 1.2 m of soil or earth on top of your house footings to protect them from damage during our frequent freeze-thaw cycle. If you remove earth below this level to install a window well, you need to provide an alternate form of protection for your foundation. If not, you could risk cracking or structural damage. When installation of your new window will result in less ground cover than the minimum, you will need an engineer to design a way to protect your foundation. To obtain a building permit, you will require a stamped letter and/or a detail from a professional engineer registered to practice in Alberta.

It is important to know that although your home may currently have a properly sized egress window, the window well may not meet current code. If you are developing a new basement bedroom, you will need to remove the existing window well and install a larger one to meet the new ABC requirements. All other types of rooms may still use the originally installed window well size. The land use bylaw has been updated to accommodate the extra width, and the requirements for one side yard to maintain 1.2 m clear for firefighter access has not changed.

Any time codes change, it can present new challenges for the home building industry. While suppliers get up to speed with the new changes, the larger wells may not be in regular stock yet. Before you purchase a new window well, be sure to confirm that the proper clearance can be achieved. It is also worth mentioning that the Alberta Building Code does not require that window wells are pre-manufactured galvanized units, which are window wells with a protective zinc coating to steel or iron to prevent rusting. Some other options to consider include pressure treated wood, decorative stone, concrete block and concrete.

Further information, brochures, requirement check lists and Building Permit applications are available on calgary.ca. If you have specific questions about building code, please contact 311 and ask to speak with a safety codes officer at the Technical Assistance Centre.