How to fix a house window that falls out?

Question

Two sets of windows on the second floor of our house fall out, due to too much space between the window and frame area. It's tight enough at the corners of the frame area, but not in the middle. In fact, I'm able to pull both windows right out with little trouble.

Here are some photos:

I'd love to hear suggestions on how I'd be able to fix. Would I be able to take off the top white flashing material and add some wood/shims? Or is the best option to add smaller pieces of wood to the top of the windows themselves to extend them upward? As the window frame seems taller in the middle (that's the really loose area), I'm thinking adding some shim material to the frame under the white part might be best.

Do products exist out there, to help with this kind of scenario?

Answer 1

There doesn't appear to be too much holding them in at the best of times. Unless you want to replace the entire window you should look at getting the top and bottom sills (or whatever they're called where you are) straight. From your description I would say that there is a pretty significant difference in the opening when measured at the edges and the middle. That shouldn't be the case at all.

Remove the trim from at least the top and bottom of the window frame and shim the top and bottom as required until you have a nice even distance all the way across. Then replace the trim and touch up the paintwork as required.

Answer 2

I'd go to a big box store and get a good quality replacement window and replace the whole thing. It looks like a old replacement window that wasn't installed correctly.