I'm about to tackle the same project as this post: egress window with header required
which is cutting out masonry in basement wall to put it a large egress type window. I am using a basement window size 48"w x 55"h, so am planning a R.O. width of 51". My house was built in 1900 in MN. I'm trying to determine the type of header I need. The rim joist construction is completely different than the house pictured.
Instead of a flat 2 by sill plate with joists and rim joist sitting on top of it, my framing on top of the 12" wide poured concrete wall is what appears to be a 6" wide x 8" tall beam instead of a sill plate and rim joist, and, the floor joists are notched into this beam about 3-4" inches of the beam cut out it looks like for each floor joist. I hope this makes sense.
I want to play it safe with the window header- this is almost directly in the middle of the 50' long 2.5 story duplex wall that the gable roof is supported by. I was thinking about using either 3or4 stapled 2x8s or 2x10s as a header for this window.
I should mention that currently there is a 34" inch wide glass block window where I will be cutting around. The glass block window has no header whatsoever, just a 1x4 barely stapled (i can almost pull out the 1x4 with fingernails) to the sill beam (don't know the proper term for this Sill plate Beam). Over the 51" wide span I'm planning to remove, there are 4 floor joists (16" on center) which are 2x8 in size. (I guess in the old days instead of joist hangers they notched joists into girders/support beams??)
Lastly, when measuring how close to the floor I am getting when planning for the 56.5" window height+sill-plate 2-by, if I add an extra 9.25" for 2x10 header, this will leave me still up about 20" from the basement floor. Is this too close to the floor? I am going to be digging well below the frostline 42" in the outside soil. It is going to be a hell of a dig through the limestone soil mix outside! (when I dug out other egress wndws, it was common to find 2'x1'x2' limestone random blocks in the soil, a good 60lb rock!).
One last question I thought of, do the headers need to be treated wood or regular? Perhaps just the exterior 2 by on the header? Any ideas to Trim out the exterior header ? maybe a big piece of flat PVC moulding?
Any ideas for the correct header support? Thanks!! Adam