Baseboards on wavy wall

Question

I have a 25 foot drywall wall left that I am doing some wainscoting... I ripped up the old baseboards, and am bumping them out 3/4" basically following this guide a bit: http://www.familyhandyman.com/walls/how-to-build-a-wainscoted-wall/view-all

So the problem is that that particular wall is a bit wavy - It was real noticeable before I ripped out the baseboards, and so I was thinking that maybe I can make the 3/4" poplar smooth it out a bit. Lining it up, I see that it can a bit, but even if it hugs the wall a little, they will be wavy to.

Wondering what the best thing to do is... sand the new boards where it's uneven, or something else?

Answer 1

If you really want the wainscoting to be straight, you could put shims behind the wainscot and baseboard to make them straight and level even if the wall isn't, and use a scribed board at the top to follow whatever curves exist there....

Answer 2

It depends on how bad the wall is. If it's within, say a quarter of an inch of variance in 4', just scribe it in as Keshlam has suggested. If it's more than that...nothing you do to your trim work is going to really hide the problem. In this case, you may want to consider setting the wainscot with a string line, and then floating the walls out to meet it (or just tearing the drywall off and fixing the walls themselves). I know this sounds extreme but I've seen what trim set on walls with serious problems looks like and it's not pretty.