Design and Decor

Complete Guide On Bedroom Egress Window Size Requirements

This is your complete guide to the right size of basement bedroom window to meet egress requirements. If you are looking for ways to gain extra space to your home, consider finishing your basement. It can be utilized as a family room, add bedrooms with bathrooms or a playroom. However, you need to build an egress window to make your plan of finishing your basement a reality according to the International Residential Code.

Let’s define it first. Egress windows are basement windows with big openings that provide an emergency exit in case of a house fire incident and other emergency situations. If you are planning to have a bedroom and living space to make full usage of your entire basement, building an egress window will be required. It provides a rescue opening in case of an emergency but also is a great way to add natural light and make your cellar feel cozy and inviting.

Below are the basic building code requirements and other information that you need to know about egress windows

Basic Building Code For Basement And Bedroom Egress Window Size Requirements

If you have an unfinished basement and are planning to renovate the entire space by adding bedrooms, bathrooms, a laundry room or whatever your space needs to function, you need to follow certain requirements for windows set by the International Residential Code. According to them, a basement and sleeping room below the fourth story must have a minimum of one exterior emergency exit and rescue opening which can be a bedroom window, patio door or skylight. Such openings that will function as a rescue opening or emergency exit must lead to a yard, street, alley, or court and they should meet the required dimensions of the window and they are as follows:

Window Opening Requirements

  • bedroom egress window sizeMinimum Opening Width – Should be at least 20 inches

bedroom egress window size

  • Minimum Clear Opening Height – Should be at least 24 inches

bedroom egress window size

  • Window Sill of no more than 44 inches from the floor

bedroom egress window size

  • Minimum Opening Area – Should be at least 821 square inches or 5.7 square feet

Important Reminder: If you will notice, the minimum opening width of 20 inches and the minimum clear opening height of 24 inches will only result in 480 square inches or 3.33 square footage which does not meet the egress size window requirements. Therefore, it means that if you choose a window with a narrow inside width or the width opening is on the narrow side, the full height of the window should be taller than the minimum height requirement in order to meet the required window having a 5.7 square feet minimum opening area. Therefore, it is important when choosing a new basement or bedroom window to carefully read the product catalog and to know if that particular type of window meets the egress window requirements. This will save you money, time, energy and most of all prevent unnecessary stress.

How To Know If Your Existing Window Meets The Egress Window Requirements

If you just moved into a new home that has a cellar, then the bedroom egress window size is most likely meets the current building code requirement. However, this may not be the case for older houses because some of them were constructed before the creation of egress window requirements. If you are not sure if your existing windows meet the current code requirements, all you need to do is to grab your tape measure, paper and pencil and then measure the following items:

You need to fully open your basement window and then measure the height and the width of the opening. Then multiply the height and width to get the clear opening.

If the product between the width and the height is equal to or greater than 821 square inches or 5.7 square feet, then your existing windows meet the standard size requirements. Therefore, you can go ahead and start planning how you would want your space to function. However, if you have smaller windows or the clear opening is less than 821 square feet, then you would be required to put up larger new windows or commonly referred to as egress windows.

Other Requirements

Basement windows also need to open from the inside because they should not be locked by a key. Therefore, any grilles, screens, bars to keep your window locked or other similar devices will need to be removed from the inside without any use of keys or tools.

Choose a type of window that can be completely opened where the window sash will not be an obstruction to such openings. This provides you and your loved ones a means of escape or the rescue personnel to quickly get into the basement in an event of an emergency.

Please consult your local building official about basement or bedroom egress window size as the requirements may vary from state to state.

What Do You Need To Do If Your Basement Windows Are Beneath Ground Level?

Older homes most likely have an underground level basement and if you want to transform this into a habitable space, you will be required to have a well underneath the window frame. Window wells should be at least 36 inches long and 36 inches wide or 9 square feet of total floor area. However, if the well is deeper than 44 inches, a fixed ladder or steps are needed. Fortunately adding steps to a wooden or concrete well is easy and you can improve its landscaping around the well by adding crushed rock or potted plants.

As for windows under a porch or deck, they need to have a minimum clearance of 36 inches between the bottom of the deck joists or porch joists and the top of the window well. The minimum clearance of 36 inches will provide enough space for an average sized adult to escape during an emergency.

Different Types Of Basement And Bedroom Egress Window Sizes And Types

Below are the different types of windows that can function as as an egress window and that meet the building codes:

Casement Windows

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Choose casement windows if you do not have enough wall space which makes it ideal for bedroom windows. This type of window opens like doors and swings wide which will provide enough opening. It opens through a rotating handle and in some cases comes with a crank feature that folds away. Therefore, the crank would not block the window treatments.

Size Opening Requirement – The window’s net opening should be at least 8 square feet.

Sliding Windows

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If you want to really transform your space into a beautiful and functional one, consider a sliding window as the egress window. Sliding windows will help you to get more natural light coming into your basement. It opens through shifting the sash from left to right which means it is only open on one side. As a result of this feature, you will be required to choose a wider and taller sliding window that will meet the minimum net opening width and height which is 20 inches and 24 inches respectively.

Size Opening Requirement – This window’s net opening should be at least 16-square feet or the sliding window dimensions should at least 4 ft. high and 4 ft. wide.

Double Hung or Double Sash Windows

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This is the type of window that has a top and bottom sash which can move up and down. The two movable sashes can be opened to give a good amount of natural ventilation. However, when fully open, the double-hung window has more than 50% or more than half of the overall area of the window blocked by glass. Therefore, you need to choose a double hung window that will meet the clear height opening for the egress window requirements.

Size Opening Requirement – In order for the double hung window to function as an egress window, the overall height should be at least 57 inches.

Tips: Avoid using awning windows because they are proven to be not suitable for basement . Aside from that, the center opening mechanism does not meet the standard code because the hardware often causes obstruction.

Things To Know When Installing One

  • When remodeling the basement of an older home, you are most likely going to need to replace the existing window with a larger one. Fortunately, many egress windows will fit in a pre existing window frame.
  • Expanding the height of the window opening will just need very little structural work compared to expanding the width of the window.
  • If you are planning to add an additional new window frame, hiring professional carpenters is needed to ensure that its solid foundation will be maintained.
  • Adding a finished bedroom in the basement requires a safety feature by adding an egress window. Therefore choose a window that not only fits the available space but will also meet the standard clear opening dimensions. The clear opening will function as a rescue window in case of a fire or other emergency cases.


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