Build in bookshelves - out of plumb

Hello all,

Planning to create some build-in bookshelves on a wall, in a corner. I was hoping to leave the back open to the wall.

The drywall walls are slightly off plumb (about 1/4" to 3/8" overall. With some wave action in there. Also, the corner is not square. Typical stuff...

Curious how to address this! If I create square/plumb carcass, and install on a level base, the shelves are not going to sit tight against the wall! In places, the frame will not sit flat against the wall.

I think this means that I am going to have to add a back (this will hide any defects that would be visible on the inside). And then use scribing and moulding tricks to hide things on the outside? Other suggestions?

I've definitely seen custom build-in selves with open backs...and didn't see gaps between the frame/self and the walls. What am I missing here? Nobody has perfect walls, right?

Thanks

Urs

 

Build everything square level and plumb... yes the unit will need a back. Youre building a box and the back will keep it square. It may need to be shimmed away from the wall when you attach it. But then plan to add an additional side piece to each side after the install. These are often made 1 1/2 wider so that it protrudes 3/4 past the front edge and be flush with the overlay doors (if any) and then you have 3/4 extra in back to scribe to the wall.

Its often best to make a straight taper cut against the wall (make the front perfectly plumb) and then float the gaps in with a 6" knife and joint compound (rather than have a wavy edge).

Another way to do it is to build your face frame so that it protrudes 3/8" beyond the cabinet sides... Then after it's installed add a 1/4" plywood scribe to each side.

 

I would not worry about the open back, ideally, once completed, you will have "stuff" on the shelves that will mask any irregularities.

If the built ins are going to be painted, then all you need is a bead of caulking. If stained, you need to fool the eye. Scribing is one way, I sometimes reverse scribe. Set the unit in place and plan on putting a small bit of bead molding The smaller it is, the more it will bend to follow the shape of the wall. I've also put molding in place, dragged a utility knife across the face and into the drywall, remove molding and then drag the utility knife at the level of the cabinet. Both times scoring the paper on the drywall. Then remove the paper between the two knife lines and carve out a small amount of the drywall. Maybe no more than 1/8", or enough that when you put the molding back it neatly slides into the void - a reverse scribe. If you get a little wonky with your reverse scribe cut and there is not a great fit, run a tight line of painters tape on the molding and fill the void with joint compound.

 

Thanks everyone! Great advice and a few options to go with.