I am building an addition with vinyl windows and want to ensure there is sufficient depth on the interior to inside-mount automated roller shades (about 4" of a drywall return with no wood trim). The walls are currently planned as 2x4 and there is a stucco exterior with no sheathing. Here's an example that is roughly the depth I'm looking for.

Example Window

From what I've gathered, with a 2x4 wall I'll end up with about a 1.5" drywall return as the windows I'm looking at have a 3.5" jamb and a 1" nail fin, (essentially giving me the 1" fin plus 0.5" interior drywall). Window nail fin diagram is here: https://windorsystems.b-cdn.net/wp-content/uploads/1550-Section-View-XO-1-inch-Nail-fin.pdf. Are there typical ways to extend this other than just having a thicker wall?

I could go with 2x6 framed walls, which would increase the depth by 2" Does adding exterior window trim or something around the rough opening (pushing the nail fin further out) make sense? Or does this end up looking strange? What other options do I have?

  • 1
    You've got me a bit confused. Usually jamb extensions are added because you've got a window designed for a wall of one thickness going into a wall of a greater thickness. I can't imagine how you're going to put a 5.5" deep jamb into a 3.5" thick wall without it looking funny and the jamb extensions breaking off (eventually). Perhaps edit to include a drawing of what you're thinking. Otherwise, I'd think that the only way to get a deeper jamb is to build a thicker wall. OTOH, a 2x6 wall gives you more insulation and whether you're heating or cooling, more insulation is good.
    – FreeMan
    Commented May 16, 2022 at 11:59
  • @FreeMan I'm probably not using the right terminology. Edited to add a photo of what I want, as well as a link to the window nail fin spec. Basically I want to know if there are other ways to deepen the window (jamb? sill?) besides the obvious of just having a thicker wall.
    – Travis
    Commented May 16, 2022 at 17:06
  • To close the loop, we ended up using 2x6 framing for newly built walls and furring out existing walls ~1.5" where depth mattered.
    – Travis
    Commented Sep 28, 2022 at 19:06
  • Please make your last comment into an answer so you can accept it and others can find it. That's good info to have and it's very difficult for others to find it when buried in a comment.
    – FreeMan
    Commented Oct 14, 2022 at 14:48

2 Answers 2


It is probably possible to get the depth you need in a 2x4-based wall by building deeper window frames. Whether or not that will look good is up to you. Without decoration it will look like an oversize boxy window frame. You could use very heavy trim to transition from the wider frame to the wall. It may look a little Grotesque (capital G) if you over do it. You need to use the engineering drawings from the blinds and window makers to determine exactly how they mount to the window frame and what's needed behind the frame.

If you haven't built the wall yet, and your design is founded on the appearance of these blinds, you definitely should go for a thicker wall and get what you're after.


We ended up going with the "obvious" - new walls were framed with 2x6 and existing 2x4 walls were furred out with 2x4s laid flat and horizontal.

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