Levelling bookcases?

You can buy little stepped wedges but, with a wooden floor, you are going to get a gap somewhere that shows. In my view, the important thing is that the top and shelves look level, people don't tend to look at the floor line. He could plane the plinth(s) but, if he moves the bookcases latter, then he'll have a problem.

Brian

Fixing varying thicknesses of gold-plated hardboard to the bottoms of the bookcases?

(More seriously, I use old PCBs for this. Fibreglass PCB is damp proof and effectively unbreakable, unlike hardboard)

The best solution IMO is to bolt all the book cases together and level the whole lot as one large bookcase. Failing that, level the floor they are going to stand on first by building a shallow base for them to sit on.

Yes. Junk the Ikea book cases and make something that actually fits, is made of something reasonable, and doesn't look like everyone elses pile of utter cheap tat.

Or if you must use them make a level MDF plinth to sit them on, and paint it dayglo pink.

Less seriously, use wedges. Then sew a nice little varying-depth pelmet to pin to the bottom shelf.

What you need is these?

I don't think it would be wise to have the weight of the books on such small things. The bookcases are very tall, and will be full.

-- Richard

I'd never use wedges (or wall unit shims) under a bookcase - far too heavy.

Tape some thin polythene to the floor where the bookshelves will run (masking tape). Choose a suitable piece of board to rest the shelves on. Mark, with tape, the edges of where the board will go. Run a thick bead of car body filler along the edge of the board, with not too much catalyst in it. Put the board down, so that the filler squeezes out onto the protecting polythene, and takes up gaps (you want a continuous run of filler, don't squeeze it too hard). When the filler is rubber-hard, pull up the board, and cut off the excess. When the filler is hard, treat the board with stain or whatever, making sure that the filler takes the colour (a marker pen might be handy). Put the board down, and stand the shelves on it (you might want to have a frame, rather than a board (or batten). N.B. the smell goes away quite quickly.

Chain 'em to the wall, just in case.

The message from "The Medway Handyman" contains these words:

I reckon that's the solution I'd go for. Build a level plinth for 'em to sit on.

...and is much thinner than hardboard giving a finer adjustment of height.

Why not build a plynth for them to stand upon, say four inches high - top perfectly level and bottom to suite the floors varying height. The four inches would help hide the variation.