How would I measure how to cut the panel pieces that will go under the slanted ceiling where my stairs go above my living room wall? In the picture shows the paneling I am doing but I’m unsure how to measure the angle needed for each piece going along the left side of the wall under my staircase. Thank you!

wood paneling along right side of wall

left side of wall showing the diagonal ceiling area under stairs

  • you don't measure the angle, you transfer the angle to a piece of wood and then adjust your saw angle to match it
    – jsotola
    Aug 25, 2023 at 15:12

1 Answer 1


To determine the angle you can use an angle finder or you can use couple pieces of scrap if you have it, hold one piece plumb and take another piece of scrap and hold it up to the angled portion, over the top of your vertical piece and scribe your vertical piece with a pencil. This will provide the exact angle of your cut.

Once you get to the angled portion, measure to the long point of the angle and make your cut at the angle you determined earlier.

To calculate the height of your next board, measure to the short point of your angle of the board you just cut, subtract whatever you would like for the spacing and that will be the long point measurement of your next board.

  • 1
    Once you get the angle right, use that piece as a template to mark all the others, that way you only have to do it once. Also, I strongly recommend the second, "mark it" method. I've got and have used angle finders, and it's just much easier to hold one piece up to the wall then use another piece (I'd recommend a ruler/straight edge which you know is square and straight over a board/scrap which might not be) to mark it.
    – FreeMan
    Aug 25, 2023 at 14:34
  • I think this is correct and it's what I would do, but I'm making some assumptions because I've done similar things before. If you could make a quick diagram, that may help clarify your instructions for people that have never done this. Aug 25, 2023 at 14:35
  • 1
    @FreeMan I agree. If OP is cutting with a miter saw they might not need to mark it with a the template but if using a circular saw I would definitely go that route.
    – matt.
    Aug 25, 2023 at 14:38
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    @FredricShope Good idea, I don't have access to Sketchup right now, I will try to make on here shortly and will update my answer. If you have one available you are welcome to edit my answer and include one.
    – matt.
    Aug 25, 2023 at 14:46
  • @matt. OP would still need to mark the angle on the saw so it could be returned to that position, because she will need to set it to 90º to cut the bottom end off square to meet the baseboard.
    – Huesmann
    Aug 25, 2023 at 15:07

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