What Do You Need to Know About Escape Windows?

Published on Thursday, 19th December 2013

Please note: Since this article was written, Approved Document B - Fire safety: Volume 1 - Dwelling Houses has been updated. The regulations have since been amended to include provisions for escape from upper floors more than 4.5m above ground level. More information can be found in Section 2 of Approved Document B (Fire Safety).

Do All Rooms Need an Emergency Exit?

All habitable rooms should have a means of escape to a safe location outside:

  • Ground floor rooms can have direct access to a corridor leading directly to an door or escape window to the outside, or an escape window
  • First floor rooms need an escape window, or a protected stair enclosure leading to an external door
  • Second floor and higher rooms need a protected stair enclosure leading to an external door.

VELUX windows are an emergency exit

What Are the Minimum Requirements I Need in an Escape Window?

Escape windows must have an unobstructed clear, openable area. The minimum dimensions are:

tickExit free area 0.33m2
tickMinimum width: 450mm
tickMinimum height: 450mm

As a basic rule, if the opening is 450mm wide, the height must be at least 750mm, which will create an open area of 0.33m2.

You should also note the window must be able to stay open without the need to be held open so both hands are free. And the pane must have safety (laminated) glazing (this is the lowest level of glazing sold on Sterlingbuild).

Where Do I Need to Position my Escape Window in the Roof?

The inside of the lower part of the frame should be no more than 1.1m above the finished floor area. A step under the window can be installed to meet this requirement.

If the inside of the bottom of the frame is lower than 800mm, guarding or restrictors must be fitted. If you have a window sill, it must be a minimum of 600mm from floor level.

This image shows where to position the escape window within the roof plane:

Rooflights as means of escape


Can I Fit a Lock on my Escape Window?

Yes, locks can be fitted but this isn’t encouraged. In an emergency, every second counts.

Where Can I Get More Information?

Planning Portal – Approved Document B (Fire Safety)

Planning Portal - Building Regulations Approved Document Park K

Local Authority Building Control

UK Fire Service – Fire safety in the home