backing coat - making a wall plumb

by Tom

I have set up a couple of plasterboard walls joined by an external corner so I can practice some plastering. I have noticed that one face of the wall is not properly vertical when checked with a spirit level. (the frame i built isn't the greatest!) In actual fact the bottom section of the wall needs to be built out more than the top in order to get a true vertical. Having watched your backing coat videos I wanted to have a go at setting up the guides and then filling in. Am i right in thinking that in the videos the wall you are applying the backing coat to is already vertical - and thats why you can parallel the straight edge down the wall after the top and bottom guides have been set? In effect you are using the existing wall as a guide which i guess is perfect if its vertical?
Would i be right to make any compensations right at the start when I am putting on my angle bead? Once I have the angle bead vertical on both wall faces then i can work from that? I wasn't sure because I notice towards the end in the video where you are setting up the guides you mention that if your wall isn't vertical then you can make adjustments to the top or bottom guides to get it vertical but this confused me. Wouldn't it then mean the guides would be out relative to the angle bead you did at the start?

Thanks for any help


Hi Tom,
The guides that you first put up will be flush with the angle bead and so will, as you say therefore be plumb. But by the time you get to the other side of the wall where you are not working to any angle beads - it is possible that the top guide is not vertically level with the bottom guide - due to the possibility of the wall being out of level. In this case disregard the wall and rest a straight edge vertically on the guides so that the top of the vertical straight edge is touching the top guide and the bottom of the edge is touching the bottom guide. Then hold a level on the straight edge to assess how vertical it is. You can then adjust the thickness of the top or bottom guide accordingly and recheck until the guides are plumb.

Let me know if this doesn't make sense and I'll send you a picture/drawing.


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