My next project is a pool deck, but after that I'm going to be converting a living room in our addition to a bedroom, putting in a second bath and so on...

As part of the project, I'm expecting that I'll need to provide egress for the new bedroom, but all I have is double-casement windows that have 15" wide opennings. I'd like to take out one window and in its place put in a new door.

So, my question is this: Will the existing header in the exterior wall framing for the current window be OK for the new door, assuming I use a door that fits into the width that I already have in my wall framing for the window?

Note: putting in a window was preferable for my wife since she likes the windows as is, I had proposed just swapping windows and putting in double hung, but she prefers to turn one window into a door so that's the plan.

 

You'll have to measure the window face trim and see how wide it is. If the outside edge of your window face trim (the casing) is 36" long, you probably have room to put in a 32" door, which would require a rough opening of 34 x 82.

If you're trying to meet an egress requirement, and want to stay with a window, take out the two 15" casements and replace them with a single casement that is 28" to 30" wide. Some inspectors won't allow double hungs as fire escapes because the bottom sash doesn't open wide enough to provide the proper egress, and they sometimes won't count the whole opening like they would with a casement.