Hello,

I am curious about installing headers over a basement window opening on the gable side of the house. I have 2x10 floor joists (14' span) and the 2x10 band joist that sits on a 2x6 sill plate on top of the concrete block foundation. What is the normal practice for installing headers in this location? Is it sufficient to double or triple up the band joist? or does the header install under the sill plate?

It depends on whether the wall above is load-bearing, and on how much load is coming down on it. If it's a gable-end wall, it's probably not load bearing, if the floor joists run parallel to the wall you want to put the window in. If that's the case, then it depends on whether it's carrying one or two stories plus the gable end.

To further complicate matters, I'm sure you want the window to be as high as possible in the wall, unless the bottom of the window will be above grade with a deep header over it.

Usually, the header would fit up under the sill plate for a basement window. There are some "tricks" like placing the header above the sill plate, shortening as many studs as necessary, but that should be done only on the advice of a qualified design professional, to make sure other relevant details are looked after properly.

Or you might use a deep steel angle header to minimize the depth. Again, a professional should be consulted.

Richard,

Thanks for the info. I left out that the floor joists run parallel with the window opening I want to enlarge to meet egress codes. Since I do have an 8 inch concrete lintel over the existing window and the grade is low enough that I can make the rough opening 32 x 48 inches without removing the lintel or changing the existing opening width my plans are to install a Pella casement window to satisfy the egress requirements (with well outside). I only asked because I have not seen an example of a basement window header when the joists run parallel to the outside wall only when the opening is supporting the ends of the floor joists.

Then you can just use the lintel as the header, and you won't need anything else above the window.