How do I even out a pair of bookcases on an uneven floor?

Question

So, I have a couple Ikea Billy bookcases, normal. I got them with doors, so with the forward weighting, I'm a bit extra paranoid about tipping.

I put them together; all fine. Then I try to place them against the wall. I find the floor is uneven. Not just slanted, but a little bowed as well. I want them flush together, but it seems if I try to get that they don't fit together right, and are not aligned vertically. I can get them to sit nice together, but then they have a slightly forward lean (I can and will anchor to my wall with a bracket at the top).

So, if I shim enough to be perfectly level, they won't stand together right and I get a little stair step effect across the top. I also get a bad gap with the kickpanel/toepanel underneath. If I have them standing together right, they're not level across the top. Is having them level all that necessary, especially since I will be anchoring to the wall? Is there something I can do to make the gaps from shimming less noticeable? Does joining them together with bolts make sense? I saw some parts from Home Depot that can bolt them together, would that help, or would the stresses from the bookcase shear the bolts? (unlikely, but as I said paranoid about tipping).

Thanks much.

EDIT: I accepted the answer closest to what I did. But this is what I did. I realized a few things. 1) the hinges on the Billy (standard Ikea hinges) don't have to be super level to work, they have a bit of a snap action to them. 2) I'm bolting to the wall, so with this and above, I don't need to be super paranoid about level, i can just join together at sorta level.

I actually got some binding posts and some breakable/adjustable length bolts. I drilled through the shelf holes in the bookcase, trying to use the ones where the hinges were anyway. This got them together. Then I did some mild shimming, and bolted to the wall. NOTE I got 3, I probably should have gotten more. I sheared one bolt by tightening too hard. If you break before Ikea does, you're not heavy duty use. Seems to work well, and very solid.

Answer 1

Attaching the bottom of both bookcases to a single flat board will get them aligned right. Then you'll just have to shim once to get things properly vertical. If the problem is extreme, consider bolts or a backboard to connect the sides of the units. Both these options will improve overall stability of the pair. Depending on the aesthetic situation, you could use anything from 3/4" BB grade plywood to birdseye maple for the boards.

Answer 2

I do not know the exact materials and construction methods used for your IKEA Billy bookcases but one scheme you could use to get them to sit nicely in their place on the floor is to "scribe" them to fit. This technique would involve you first clamping the two units together using some C-clamps. Make sure to put some protective material under the clamp faces to protect the book shelf veneer or laminate surfaces.

Next you place the book cases in to their intended location and use some 1x2 pine board strips which you will clamp onto the sides as temporary "stilt" legs. Clamp these into place so as to get the while unit vertical and even. When you do this note the highest spot on the floor (i.e. the part of the floor that has the smallest gap underneath the stilted bookcase unit). Ideally you would be letting the floor support the parts of the bookcase that has the narrowest gap so that the gap at that point approaches zero.

For the scribing operation you want to either use a scribing tool (see picture below) or find a small piece of material that has a thickness approximately equal to the largest gap between the floor and the bottom of the bookcase. Let's say the largest gap is 1/2 inch. You would use an item that is 1/2 inch thick (or set a scribing tool to 1/2 inch). Now slide the small piece of material along all the lower edges of the bookcase as it sits on the floor. In each position draw a line onto the sides and front kick pieces of the shelves. (The scribing tool would have its straight arm drug along the floor surface while the pencil draws a long onto the shelf side).

The next part of this scheme is to saw along these scribe lines and cut away a small part of the sides and kick boards. If done correctly the two shelves will now perfectly match to the floor at their intended position and be nice and vertical and straight.

Here is the picture of a scribing tool. Get these at most hardware stores or home centers that sell tools. A standard short pencil fits into the one side of the tool. Set the point of the pencil to be approximately even with the point on the other arm of the compass/scriber tool.

Answer 3

There are two ways you could do this, both start with shimming the bookcases so that the doors operate the way they should. The shelves do not need to be perfectly level and plumb, they only need to look that way so they do not draw attention from being out of level or plumb.

After the shims are set the way the shelves or better to say, doors work the best, measure the gap at the floor at the widest dimension there is. If you have a compass scribe, you set the scribe to the widest part of the gap, mark it, and cut the bottom to conform to the floor. You could use a pencil with a gauge block of the right thickness to do the same. Maybe even pinch the pencil between your fingers to keep it a consistent height as you mark the bottom will work too.

The other way is to add another piece of small molding around the bottom to conceal the shims, or adding another piece of base to do the same. This might be simpler being the bottom has a recess that will require a number of small pieces of molding to do the job, where a new base will cover the recess. The base might need some trimming to follow the area better, since the floor varies.

Answer 4

In weird situations like this I have just screwed the bookcases to the walls. Take the highest point in accordance to the floor and screw them in. Obviously you might need some anchors, brackets, or other helpers but this is often the easiest way to deal with this situation. From there just build up the legs with shims or other suitable materials, so that the bookcases have a little of the weight offset to the floor.