I need to add the trim to a window.

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I don't care about beauty too much. All I need is an L shaped wood trim. The "reveal" (I think that's how it's called) is 3/8'' inside the wall, so I need this specific dimension for the L shape to go inside.

Question: Is there a way to find this specific trim size online, or do a custom order somewhere.

Alternatively, am I better off just nailing in a 3/8'' frame to the reveal, bringing the reveal level with the wall, and just nail in wider wood boards to cover the gap between the reveal and the wall? The look would be fine, I am just not sure what is the better way of doing this.

Yet another option is to cut the L-shape myself, but it looks tricky to get it right.

  • I normally make the sill wider and it’s a lot easier. The photo is out of focus and the full frame is not in view. I am sure you could make something that would fit if it is assembled a bit tighter than that corner it may not look two bad.
    – Ed Beal
    Commented Feb 23, 2021 at 21:42
  • Added 2 pictures. Can I find something in the store for this or do I have to build it?
    – Manu
    Commented Feb 23, 2021 at 23:23
  • Will probably need to add to window frame to extend to wall, then use store bought trim to cover. Probably buy a 1x3 piece and cut pieces to size(3/8) and nail/glue to frame.
    – crip659
    Commented Feb 23, 2021 at 23:45

1 Answer 1


Yes you could add another jamb extension to the jamb extensions that are there already. The down side of that is the joint will look out of place if you try to add the new wood flush with the original, or if you step it back to make a new reveal, (the reveal you referred to is more of a projection of the wall or recess of the jamb extension) to me it makes the inside of the window opening too "busy".

If it were mine to trim I would use 5/4 material (1" thick") and table saw a relief to accommodate the wall projection.

That being said, if you have trim elsewhere in the room that you will need to match up and it is not thick enough to cut the back out, then you may need to add to the jamb extension, so you can use an off the shelf trim.

  • I had a similar situation where I had to extend a modern interior door jamb to match the thickness of a wall built with true 2x4s. Once I put the jamb extensions in, I ripped thin (roughly 1/8") veneers from a 2x6 to cover the door jamb to make it look like it was a solid piece. I then stained the whole frame with the veneer in place for the final finish.
    – FreeMan
    Commented Feb 25, 2021 at 15:49
  • @FreeMan I was considering as an option in my answer to pull out the old jamb extensions, and replace with deeper ones, but for a DIY project, it may have been more than one would want to get into.
    – Jack
    Commented Feb 25, 2021 at 16:02
  • @Jack. Sorry, could you please say how what you are proposing is different from a jamb extension? I am a little confused and am not familiar with the terminology. Once I have window and wall level, my "trim" will just be nailing in wood boards, which is the style I have in every other window and I don't mind it.
    – Manu
    Commented Feb 27, 2021 at 0:23
  • @Jack: Re-reading your message, you are suggesting that I table saw a single piece that will just fit in place, which is what I was saying with the L shape? If so, what tool would be best, can I use a jig-saw or circular-saw, or do I need a table saw? The window is 8 feet long, so I would need about 9 feet boards. Thanks.
    – Manu
    Commented Feb 27, 2021 at 0:27
  • I was giving you a few options of which you have already mentioned both of them in your question. The "L" shaped piece would be my preferred choice, and is best and safest to be cut with a table saw. It can be done with a circular saw, but the chance of cutting the piece inaccurately would be very high, and not being safe. I have attached my circular saw to a piece of plywood to make a table saw out of it and screwed a wood fence in place to guide the cuts. A jigsaw would not be the right tool to try this with.
    – Jack
    Commented Feb 27, 2021 at 5:02

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