I have a curved stair case and I'm looking to drywall it up going into the basement. I'm looking for guidance on how to best frame the area below the stairs to drywall it up.

Images of the bottom of the staircase, looking up: enter image description here

enter image description here

  • Hey Kermit, i know it aint easy being green but can you turn the photos so they are oriented properly. What does "drywall it up" mean. "area below the stairs" ?? Please explain in detail what you are try to accomplish. – Alaska Man May 27 '20 at 17:04
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    @AlaskaMan - I think they are oriented properly and we're looking at the bottom of the top rung of steps. Second photo shows both the steps the photographer is standing on and the steps above them. – PhilippNagel May 27 '20 at 17:54
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    @PhilippNagel The first photo was completely disorienting to me but i now think it is the underside of the stairs above. That makes "drywall it up" make more sense. I think i would custom make a skirting to fit the contours of the steps with a nice straight edge on the bottom side to but the drywall to. – Alaska Man May 27 '20 at 18:23
  • @AlaskaMan do you have examples of skirting? – Kermit May 27 '20 at 19:17
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    @AlaskaMan I was right there with you for a few moments. Very disorienting at first. – FreeMan May 28 '20 at 14:20

I would install thin, flexible boards against the wall and mount crossbars (ceiling joists) to them. I would not mount drywall directly to the stairs.

  1. Establish lines on the wall. This could be done with semi-rigid pipe held against the staircase to create smooth curves.
  2. Rip 1x4 boards in half to yield 1x2 boards with nice square edges. 1x2 lumber usually has very rounded edges.
  3. Mount these runners on the line with the narrow edge and square corners against the wall. Use 3" construction screws and pre-drill so as to not crack the boards. If you find the curves too tight, soak the boards in warm water for a few hours.
  4. Mount 2x4 boards flatwise across the span, screwing them into the runners with 2-1/2" construction screws. Pre-drill here, too.

This strategy, along with the corner tape joints, will leave you with a very strong ceiling. It'll be isolated from the staircase, so that any vibration and movement in the stairs won't result in cracks.

| <-- wall
|          | <-- 1x2 runner, screwed to the wall studs
|     2x4 ceiling joist, screwed into the 1x2 runner

One suggestion for fitting the drywall (the most challenging part of all this) is to do it one side at a time. Fit pieces that run about 2/3 the way across the span to the wall. Do this from each side, mounting loosely near the walls and lapping the center area. Then use a rotary cutter to slice up the middle through both layers. Remove the scrap and screw it all tight.

  • +1 for isolating the drywall from the stairs themselves. – FreeMan May 28 '20 at 14:23
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    Actually, cutting the curved drywall may be the hardest part of the project. The only thing I can think of is cutting the curved pieces out of the center of 4x8 sheets, throwing away large parts of it. Any other suggestions? – FreeMan May 28 '20 at 14:32
  • Nope. I did update my answer to that effect. Drywall is cheap in most areas, at least. – isherwood May 28 '20 at 14:47

Use 1/2" plywood ripped 3 3/4" wide, pushed into the wall, with the top edge following the slope of the stairs on both sides. You may need to use a thinner plywood to conform to the inner radius but the idea is to conform to the radius and the twist the wall will make the plywood do. do 2 layers of 1/2", and 3 layers if you need to go with a thinner plywood. After that is done, cut 2x4s to go between the plywood strips. No the 2X will not line up perfectly on either side meeting the plywood, because the inside and outside are at 2 different angles, but it will work for drywall. When done the framing will look like the spokes of a wheel radiating out from the center. Use the risers to establish the line to follow for your framing. If you cannot get 6' 8" to the finish for code, rip the plywood 1 3/4" and set the 2x flat.

Use 1/4" drywall for the ceiling, it will conform to the helix, the ceiling is. use 2 layers in your framing you place at 8" centers on the tight radius so it will be perhaps, 12-16" centers at the larger radius. Closer framing centers the better.

  • Some good suggestions here, but the problem is that the plywood needs to curve both sideways and vertically--this isn't a simple helix shape. – isherwood May 28 '20 at 15:34
  • It can be done, that is how housed spiral staircases are done nowadays, but with wider material Then a veneer is glued to finish it off. It wont be easy, but it can be done. It may take 2 people to do so. If 1/2" plywood is to tough, then go to multiple layers of 1/4, or bending plywood. – Jack May 28 '20 at 15:56

I would put some furring strips on the bottoms of the stairs. Then attach the drywall to the furring strips, I would want 3 for most stairwells. Enclosing this will help improve your tape and texture skills.

  • Putting the furring strips on the bottoms of the stairs at an angle? I want the drywall to be smooth and continuous, not pieced for each step. – Kermit May 27 '20 at 19:17
  • Bridge the steps with continuous strips screw into the bottom of each step , your pitch should be the same or very close for each step. I have done this on straight stairs many times as my jurisdiction requires them to be closed and Sheetrock is cheaper than boxing in the stairs the furring strip allows enough room for small items (you won’t have because boxed) to make it to the bottom. If you want to see how it will look take a board and lay it on top of the stair tread you have the reverse underneath see the contact points that’s where your screws go to hang the furring then the Sheetrock. – Ed Beal May 27 '20 at 22:51

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