DerbyDad03 wrote:
I want to replace a double casement over my sink with a 2 view slider.

I hear that casement openings can be tricky to measure, but mine looks
pretty straight forward.

The window is set back a little over an inch from the front of the
opening and looks to me like when I remove it, I'll have an opening
with four flat sides with some holes where the hardware is mounted.

From what I can see, it looks to me like I should simply measure from
side to side and top to bottom on the interior of the opening.

Am I missing anything? What should I be looking for?

It takes a week (from Tuesday to Tuesday) for my supplier to get a
window, so I guess I could take the existing window out and see what I
really have, then board it up for a week or so until the window comes
in. I know that would work, but I doubt the pros would ever do it that
way.

Any suggestions? Thanks!

Are you using "replacement" windows that sit inside the old frame, if it is
still solid, or are you using "new construction" windows that sit within the
house frame?

If you are using the first, you need the measurements of the clear opening
available within your existing window's outer frame after you remove all
removable items. Your manufacturer will tell you if you need to deduct
anything from the measurements that you end up with.

If you are using the second, you need to remove the window casing on the
inside and measure the outside of the old window frame, be sure that it
hasn't been shimmed up to accommodate the wall thickness with narrower
material than the actual frame is made with. Check outside to see if there
are any additional constraints such as bricks and other trim that can
complicate the installation.