I'm renovating a bedroom in the basement, and I am trying to upgrade the window to meet the local egress requirements (Ontario, Canada). We have a standard bungalow with cinder block walls, built in 1958.

As you can see in the picture, there is a wooden frame in the opening of the cinder block wall (I have already taken out the actual vinyl window). If I take out the wooden frame, there would be more than enough room to get a window in that meets the local egress requirements, however with the wooden frame there isn't enough room. So I'm looking for some help in working out if the window frame is actually structural.

There doesn't seem to be any weight on the top of the window frame from the sill plate, as I can wedge a screw driver in there and wiggle it around a fair bit. However I'm concerned about the sill an having 2 floor joists sitting on it without having any support underneath. It seems odd that the window frame would be structural, but this is a 1958 house I guess.

Basement window

Can anyone provide any pointers on how to know if it is structural or not, and if it is structural, is there a way I might be able to replace the frame with a metal lintel or something?

If I can't work out for sure if its structural or not, I'm thinking that I'll just leave the top and sides of it in place and cut a larger opening in the cinder blocks at the bottom, I'd really rather avoid that though.

*Note that I am not trying to meet USA egress requirements, this is for Ontario, where you only need a 3.8 sq ft opening (from what I've researched). I'm planning to put a hopper style egress window in, similar to this one https://bavarianwindows.com/product/egress-window-ontario/

  • Well, if it wasn't there you'd be counting on the rim joist to hold up those two joists. I always assumed the rim joist just prevents racking and not to be structural, because it's usually a fake LVL (otherwise shouldn't it be an actual LVL?)
    – Mazura
    Mar 2, 2019 at 5:58

1 Answer 1


No standard 50s wooden window frame is supposed to be structural. The rough frame of a window can be, but you don't have one.

It doesn't matter. You have a situation that requires a metal lintel. Brace the floor up just to be safe (I wouldn't work under those joists without something), install a lintel and then the window. Avoid lowering the bottom sill anywhere close to below grade if possible.

If I have to explain how to brace a floor up, install a lintel, or whether or not you need to do any of those things, it might be best left up to a professional.

  • Thanks Mazura, I might not have been clear enough in my question. I think what you can see in the picture is the rough window frame. I took out a window that looked like this one images-na.ssl-images-amazon.com/images/I/… a fairly new standard vinyl basement window (maybe 8 years old or so). So what I'm left with here in the picture I what I would guess you could call the rough window frame, or is there something that tells you it isn't?
    – Andrew
    Jul 13, 2017 at 1:10
  • @Andrew - If it is, it's not to be considered structural: improper header. A structural lumber frame header would be at the very least, two 2x4s stood up with a shim of plywood in between, making it 3.5" thick like the rest of the wall.
    – Mazura
    Jul 13, 2017 at 1:14
  • @Andrew - That doesn't mean it isn't, but with what you say about sticking a screwdriver in there, I'm not too worried.
    – Mazura
    Jul 13, 2017 at 1:43
  • @Mazura, with a little investigation on the OPs part, the builder may have doubled the rim joist in that area.
    – Jack
    Jul 13, 2017 at 4:25
  • Looking in the 2012 IRC book, figure 502.2 shows a similar condition where a span of under 4' does not need a double header. This condition in the picture the rim joist is spanning on more than between 2 joists as a header would, in my experiences working with engineers on single family homes for over 22 years as a supervisor, this condition in the picture is still stronger than a single header that is allowed by code
    – Jack
    Jul 13, 2017 at 14:33

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