I want to place plasterboard against some interior walls (garage conversion)

I want to batten out the walls with timber and back the timber with Damp Proof Course (DPC).

I already have this timber, this DPC, and plan to purchase this plasterboard (50mm)

The wall I'm battening against is not level. It's not out by much though, at most 8mm.

So far I've researched into using these shims behind the timber but I'm not entirely confident in the method which I'm going to use to get the entire wall straight.

What's the suggestion? A long piece of string at 3 points which spans the wall? Use a 1M spirit level?

What about trying something like this: https://www.youtube.com/watch?v=FuCE8xaxg2s - this seems like a waste of timber though? (planing the timber down)

1 Answer 1


You simply need to establish lines on opposite sides of your wall, then pull lines between those lines to create the plane for the rest of the boards. Use a level where desired to compare the two initial lines to check for twist in your plane.

  1. Find the high point on one side (or top/bottom, depending on your strategy) and set lines on nails at each corner on that side. Do the same for the opposite side.
  2. Check for twist in the overall plane by checking plumb between the top and bottom corners with a bubble level (and straightedge, if needed).
  3. Install boards to those lines. Fasten the board at the high point and shim out as needed at the other mounting points.
  4. Work across the plane established by these two boards, moving a perpendicular line to each mounting line as you go.

For example, if you're installing vertical furring strips, the first two lines would also go vertically, at the same locations as those strips. Then you'd check plumb on those lines. Then you'd set the first two strips. Now you move your lines to horizontal, against the first two strips, setting the rest of the strips to those horizontal lines. The first two strips act as your reference for all the other strips.

  • Thanks, I've come up with a crude image of what I think your instructions are, please could you verify for me? imgur.com/a/XXgBBI6 @isherwood
    – Robbie
    Jun 15, 2020 at 20:47
  • Not quite. I've added to my answer in hopes of clarifying.
    – isherwood
    Jun 15, 2020 at 20:58
  • Thanks again... another crude image: imgur.com/a/8RKd6VB if this is the case, why use the first two strips as reference? Couldn't the wall become more uneven the further you go along (thus making your reference strips out of alignment?)
    – Robbie
    Jun 15, 2020 at 21:14
  • Lines must always go as far apart as possible or error is magnified exponentially. You're setting the first two lines at opposite ends of the wall. The secondary (horizontal) lines span between them.
    – isherwood
    Jun 15, 2020 at 21:24
  • Understood, thank you very much!
    – Robbie
    Jun 15, 2020 at 21:24

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