Min. Size For Basement Bedroom Window, Slider Type

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Posted by: from Enfield
2/22/2013 at 3:27:55 PM

I need to order a window for my basement. I am putting a bedroom in. What is the code size needed?

Looking at a slider type window. Have more room to work with, width then height. Will need to dig out some anyways.

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Steve from Bath Revival in Oshawa
Date/Time2/22/2013 at 4:14:52 PM

There are a couple of considerations. Floor area to actual (not including frames) window pane size ratio and the height. Two important factors are ability to get out in case of fire and light / ventilation. Depends on the city but I think it is usually 5% of total floor area. Best to check on city website. It usually on there.

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Date/Time2/22/2013 at 4:18:18 PM

Good luck with your renovation and new bedroom

The window size will be on the floor plan of the building plan/permit that you have.

Remember that a 3x4 sliding glass window only allows 1'4" x 2' opening and its very awkward to open and escape when there is a fire or earthquake.

The window is for safety and egress.

I suggest you put in a larger window than the minimum required.

For safety, it is wise to have a walk out window

3x4 or 4x3 windows have a tendency to have a dresser put under them.

Manufacturers say to screw dresser to the wall but no one does...and then when someone has to escape they climb up the dresser to get out the window and the dresser falls on insurance if the dresser wasn't screwed to the wall and the person was injured or they are large, elderly, young or handicapped and they cant climb up the dresser to the 4' to get out of the window

I trained in fire protection and structural and really feel very strongly that the window needs to be step up walk out to protect your family and for resale...I would not have a 3x4 or 4x3 which is 1' 4" x2' window in a basement bedroom when it is the egress.

Perhaps try climbing our a bedroom window that is the size you are thinking and you will see the difficulty getting up and out a ask you grandmother and 5 year old!!


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Date/Time2/22/2013 at 4:30:13 PM

A basement bedroom window needs to have a minimum openning area of 3.8 s.f. with no dimension being less than 15 inches.The window sill can not be more than 3'-3" above the finished floor. If it opens into a window well you need 21 5/8" clearance from the window to the window well.

We have found that an awning window works best for this application and there are companies that make windows just for this purpose.

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Date/Time2/22/2013 at 4:36:23 PM

Min 3.77 sf and no smaller dimension than 15 inches. Clearance in from on the outside 21.7 in and should not be higher than 5 feet off the floor.

I personally just make sure that it exceeds the minimum standard. Better safe than sorry!

Good Luck!

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Date/Time2/22/2013 at 4:40:35 PM

The code size needs to be width x height of the opened part of the window needs to equal or exceed 3.8 square feet. It is called egress and is sized not only for escape in case of fire but also needs to be big enough for a firemen to get in.

In the case of fire and smoke a person can't survive more than a couple of minutes, so that is why it is determined that way.

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Date/Time2/22/2013 at 5:43:11 PM

Depending on what city you live in as some codes vary by municipality. The usual standard is a window of no less than 15" in height by 30" in width.

Good luck with your project, I hope this has been helpful.



HomeWorks by Design

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Date/Time2/22/2013 at 6:10:58 PM

Hi Heather,

I'll give you the minimum required. But I suggest larger if possible. The bigger the better, not just because it is safer and easier to escape. But Think about the extra natural light a larger window provides.

Minimum required is: 3.8 sq' The openong must be 24"x24". Maximum sill hieght from the floor is 4' 11".

Agian, if you are changing out and installing a new window anyway. bigger is better.

Hope this has been helpfull.


James Fram

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Date/Time2/22/2013 at 7:10:47 PM


Looks like you have the answer(s). Bottom line is that it must be large enough for a adult to go through in case of an emergency. Your window supplier should know what to suggest.

Also look at window quality, especially if you are planning to use the room for more than just storage. The number of panes and type of material used in the frame all make a difference. I loke vinyl and would suggest double pane. Mid-range in price but worth the price.

Good luck.

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Heather in Enfield
Date/Time2/23/2013 at 10:20:22 AM

Room size approx. 11 by 11.

What dimension does the window need to be. Would 42 by 24 work?

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IPD Consulting and Designs in Elmvale
Date/Time2/23/2013 at 11:39:41 AM

The Ontario Building Code requires under Table a minimum of 5% of the floor area for natural lighting by means of glass area; further Section requires: if there is no door from the basement directly to the outside to have a minimum opening size of .35 sq metres (3.8 sq feet) with no dimension less than 380 mm (15 inches).

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Frank from Cristo Group in Manotick
Date/Time2/23/2013 at 8:27:06 PM

You need a window 36 x56 to meet code.

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Date/Time2/24/2013 at 12:44:20 AM

Hi Heather

You have got all of the approx. sizes. By your sizes you need a window width of 44" and height of 26", but this size is good only if you use a double slider lift out window (energy star quality is preferable). This window will slide both sides and for fire (or even for cleaning...) you will slide it to the middle and raise the glass and pull out the whole sash (glass and frame) and the same with the second one so you are left with the frame of the whole window only! And that's the size that will be good for your application.

Thank you

Harry C.

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