Can I have an office basement with no windows?

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Posted by: from London
5/6/2020 at 11:46:00 AM

I have a finished basement in an older home (in London, Ontario) that we currently use as recreational room, it has a small window but not big enough to be an exit window as the basement was built way before egress window requirements. Now I want to convert this room into an office and use a portion of the basement for storage. I'd like to close the window as it will take up space where id like my storage to be, but that would mean no window in the basement. Is this legal?

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Date/Time5/6/2020 at 1:39:00 PM

I am not sure about the Ontario laws, but in Quebec, for a basement room you must have an egress window, you can contact your insurance company for more information

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Date/Time5/6/2020 at 4:45:43 PM

In Alberta egress windows are only required in bedrooms of Part 9 (unsprinklered) buildings. I would think it would be the same in Ontario as all Codes are based on the National Building Code with only some minor differences between provinces.

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Dave from 360renos in Ottawa
Date/Time5/6/2020 at 7:15:43 PM

Hi Carmen

The Ontario Building code does have some differences that are more stringent than the National building code of Canada.

You do not need a window in the unfinished, storage room area of your basement as per of the Ontario Building code.

You do need a window in the finished part of the basement. So your office would count as the finished partition. In that room you need a window that is the equivalent to the size of 5% of your office floor area.

This is not an egress requirement it is a light requirement.

Best to talk to the building department in your city. They are helpful and have no problem guiding the homeowner with the right information.



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Date/Time5/8/2020 at 10:12:15 AM

Hi Carmen,

In Ontario you basically need an Egress window if you sleep in the basement, then you need a second fire escape when the first is the stairs.

as far as day light goes, you need in privet spaces 5% and in public like living and family rooms 10%

if the house is over 5 years you can do with half of this sizes.

in rooms like rec. office and storage you do not have to have window,

just go to your city permit department and verify with them if London don't have a different bylaw,


Harry C.

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