Replacing windows with new sizes-Want to Do it right

Hey all, thanks in advance for your help.
I am replacing 15 single pane windows in an older house. They are all 2'x4' double hungs, installed horizontally. I would like to install new Pella windows that take up the same width (4') but need to extend the length of the RO. This was my plan, but want to see if it is right/wrong as far as bearing the load while I work:

Since the width will stay the same, the king studs do not move. The cripple studs over the header stay the same as well.

My plan was to rip the lower jack studs down to size with a circular saw, and install a new sill at the correct height. What I do not know (and maybe more) is how to treat the trimmer studs while working. They are bearing the load of the header, but when I remove the lower jack studs and sill, that baring goes away.

Is there a correct procedure that anyone can recommend to change the height of the sill? At least the king studs stay as-is and I can just pad the trimmer studs appropriately at the end for the RO.

Hope that makes sense. Thanks all.

 

Your king and trimmer studs will both remain unchanged. The bottom of your rough opening will be framed between trimmers at whatever height you choose.

 

Just looking at a framing diagram to make sure I am getting it 100% correct. The King studs will stay the same since the width does not expand. BUT since the Trimmer studs sit on the sill, when I remove the sill to make it lower the trimmer studs fall short of hitting the new lower height of the sill. Don't the trimmers need to sit on something to provide stability while making the sill lower?

Thanks much for your help.

 

I'm assuming you haven't torn anything apart yet. It's possible that your sill is cut between the trimmers, not between the kings. You'll only know for sure once you tear it apart and see. At any rate, when you remove the bottom of the rough opening, you will likely reciprocate the old "sill" off, flush with the trimmers. The trimmer on each side will stay put, and it's possible that 1 1/2" of the old sill will remain sandwiched there.

You will then frame in the opening as needed for your new "sill". If needed, you can add additional framing onto the lower half of the existing trimmer so that the new "sill" can sit on something in addition to being toenailed to the trimmer.

 

AHHHHHHHHH... I think I understand what you are saying now. I have not torn anything out yet for this exact reason.
So when cutting the sill, I essentially leave enough to bridge the gap between the Trimmer and the Jack so that line becomes flush.

 

dcislander,

You got it!!