I would do a mock up if you can. Use a sheet or anything that could look like a curtain for this purpose. I would start by trying 2 feet past the window opening and go from there. Use tape to hold them up and eyeball it. I usually go well past my windows. I would say approx 2 ft. However, you should try a mock up to see where you like it best.

For the width Amy photoshopped it looks like each stack is about 2/3 the width of each door when fully opened. Right, Amy? Looks good to my eye.

Approximately. Hard to judge when I just grabbed some curtain photos though.

Wow, thank you!

It's hard to tell which of the doors open. You don't want the panels to be in the path of the drapes.

Good point, ratherbesewing. They open from the center

The rule of thumb to allow for stack back space is

thin curtain material = width x 1.1

lined = width x 1.15

blackout = width x 1.2

heavy curtain material = width x 1.25

Suero, I'm confused. Would that be width of the window or width of the drapes? Either way how does the stack back end up being bigger than the window? What am I missing?

Two questions to add to your plans:

- Do you want the type of curtains that pull back from the middle /you have curtain on two sides ... or do you want the type of curtain that pulls to one side /you have only one large puddle of curtain?

- That's a looong curtain rod. I think you might need a support mid-way along the curtain rod ... otherwise the rod might "bow" in the middle. OR consider going with a ceiling mounted rod.

Mrs Pete- split in the center and pool to two sides. The product requires supports every 5 to 6 feet. The curtain length is just going to kiss the floor.

Hi, Suero- I would like clarification on how that works as well. Thanks!

Let's do some math here. 147 inch wide window. So lets call that 12 feet even though with trim it could be more like 13 feet.

12 feet plus 2 feet + 2 feet (random conservative guess at stack back at each side) =16 feet. Supports every 5 feet. Curtains don't usually slide past the supports. How does this work if you have 4 supports?

|| 5 ft || 5 ft || 5 ft || || denotes brackets

You may not be able to have any stack back off the glass if you end up with a bracket in the middle and on each end.

To clarify my numbers. Take the width of the window. Add 10%., That's width x 1.1. Thar's how much the total width of the curtains will cover. When the windows are pulled back all the way so that the window is completely uncovered, the amount of wall that the curtains will cover is 10% of the width of the window. That is. you have to allow for, in your case, 14.7 inches of wall space to be covered when you open the curtains fully. This is for light weight unlined fabric. You will have more of the wall covered with heavier or lined fabric, according to the formula I gave in my previous comment. As for not being able to pull the curtains back over the needed supports for the curtain rod, you can get a curtain rod that will let you do so. You need to look for a specialty rod, not one where the rings surround the rod.

RNmom: this particular brand of support will not block the curtains traveling. I has the same question!

Suero: now I get it- thanks!