Building regulations require that certain rooms within a dwelling need to have sufficient means of entry/exit other than the room door. This is usually provided by an opening sash of a window. The window should have an unobstructed open able area that is at least 0.33m2 and at least 450mm high and at least 450mm wide (the route through the window may be at an angle rather than straight through). The bottom of the openable area should be not more than 1100mm above the floor. Please see our flying mullion egress window. If a window hasn't been made to an egress specification when one is needed, the window will usually have to be scraped and a new one made. Please clarify whether your local building control requires egress windows. If you need egress, please quote EFE in the quote request form .