Installing new walls & windows.

Currently I have a 20' X 14' sunroom with (2) sets of French doors leading into the house, the room was obviously a porch at one time & the previous owner tied a roof into the main trusses, put a roof on, dry-walled the ceiling and installed (7) sets of sliding glass doors. The problem is, this house is in Florida, the room is not climate controlled & with the glass doors its like an oven in there! So we decided we'd like to take out all the sliding glass doors, except for one set, & instead build walls in their place with sliding low-e windows. I purchased (4) Jeld-Wen windows from HD, & figured I would remove the sliding glass windows, screw the windows in place up into the existing header, then build the wall up to it and around it. The problem is the track around the window between the outside flange to the inside one is 2.5" and a 2X4 is of course 3.5".
So my question is how do I build this wall to accomodate these windows? I know this sounds silly, but I was considering ripping down all the 2X4s to 2.5"......briefly mind you, but I don't know how to do it.
Any helpful advice or links you could send my way would be greatly appreciated. I'm pretty handy around the house & thought I could figure this out, but I'm stuck.

 

Just to help you grasp the order of things:

You would first remove the doors... then frame the walls with either 2x4 or 2x6, depending on your needs... you would leave rough openings for the windows that are the correct size (usually 3/4 to 1" larger than the windows are)... you would install sheathing on the exterior... then building paper... then the windows.

You mentioned that your windows are not as wide as the wall is. That means that after the windows are installed, you will need to trim them. Drywall can return to the windows, or they can be trimmed with a jamb (stops) and casing.

 

Oh, ok, so I should have that "rough" of an opening? (3/4" -1") seems a bit much, do I nail in 1/2" ripped plywood for a better fit? Or is it okay to have that much of a gap around the window? How important is it that the window is snug inside the opening?
I'm trying to make this room as efficient as possible.
I spent the better part of last night figuring this out & with your comments I think I have a good handle on the installation of the windows except for two things...once I have constructed the openings and the windows are ready to go in. I'm confused because there are no holes in the frames of these windows....how do I secure them to the "rough out"? Do I drill through the frame and screw it in, is it not suppossed to be screwed in?
Secondly, the frame has (3) flanges, it kind of looks like an "E" with the backside being where the window is & the top of the "E" being the outside facing side & being twice as long as the other two flanges. (1) on the outside facing side (top of the "E") which I figured goes over (in my case) the plywood & Tyvek, but then moving in towards the inside facing side of the window, there's another flange (the middle finger of the "E"), about a 1/4" tall that follows all the way around the frame and then finally another 1/4" flange on the inside facing side of the frame...My question is why are those (2) flanges there? And short of grinding them away (which I doubt I'm suppossed to do), if I secure the window with them in place, that'll leave a 1/4" air gap all around the window, is this for some reason I can't fathom?
Thanks for your help in this.

 

3/4 - 1" of space is allowed in the sizing of the rough opening so as to be able to level and square the windows inside the opening. (not 3/4 - 1" per side... but for the total opening. it is actually about 3/8 - 1/2" per side) You install shims at the corners of the openings to do this- Two tapered shims are sandwiched together in opposite directions until you have a nice fit. The remainder of the space is insulated with fiberglass or low-expanding window and door foam such as DAP Latex Window and Door foam. I always recommend it because it's fool-proof for DIYers and will never bow frames.

I'm assuming that on your E shaped piece, that you must drill your own installation holes in the longest flange, and that the other 1/4" tall flanges are there for strength. They help keep the side of the window rigid. You would not grind them off!

 

The information XSleeper is giving is right on target. If you want to see what it will look like when you are through, I just finished 3 enclosures in a row on the same street on the side of a mountain where I live. For information ONLY, you can go to http://www.chandlerscarpentry.com/projectsone.html and scroll down. Some of the windows had stools, some framed, and one room was a combination. One owner wanted a stepdown into their room, while another didn't want a stepdown. We removed a 10' wide door and a 6' wide window, making two entrances into the room on the last one. Good luck with the project, and post back is we can help further. And thanks to whomever turned my HTML and smilies back on!! I have missed them.

 

Wow, beautiful rooms, they actually look a lot like what I'm envisioning the room I've been talking about!
Except for my windows being longer (width) and shorter (height).
Okay, so let me see if I comprehend what you're both saying; the "rough in size" (the size Im going to be building) should be "roughly" 3/8" - 1/2" larger all around than the actual size of the window Im installing right? So that when I actually install the window there will be gaps, which I will then shim in with the plastic shims I could buy at the HW store, right?
Then check the level & the height all around and go ahead and drill holes through the frame from the inside out.
Then when I have this all secured I should spray in some expanding foam for the gaps (you recommended DAP, I love that stuff too).
Am I getting it?

 

>>there will be gaps, which I will then shim in with the plastic shims I could buy at the HW store, right?

I don't care much for the plastic shims... cedar shims are better IMO- easier to cut with a knife.

>>Then check the level & the height all around and go ahead and drill holes through the frame from the inside out.

Actually you can predrill the holes in your nailing fin before you set the window into the opening. (Drilling from the outside of the window toward the inside.) With vinyl windows you will shim the bottom corners so that the window is setting on them. Then you might also wish to install 3 pair on the sides at the bottom, middle and top. I don't like to rely on nailing fins to keep vinyl windows straight. I'll loosely tack the nailing fin at each corner with 4 screws, then shim the frame until I like it, then install the rest of the screws as needed.

As you install the windows, you should level the bottom, check the frame for square (measure the diagonals- they should be equal) then plumb the sides, ensuring they are straight.

Sounds like you'll do fine.

 

Okay, I got it loud & clear, my only question I have left is "nailing fins" what in the heck are they?
Is that the flange that runs the full circumference of the frame?

 

Yes, they have holes/slots cut in them for you to fasten them flatly to your tyvek covered osb. Always a snap to use them on new construction. Thanks for the comments on the rooms. I thought you would like to see what yours might look like. Cool.