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I have a (now-discontinued) Jonas desk from Ikea that is several years old: desk

The desktop has gotten kind of worn and is a little small for my current needs, so I've been considering replacing it with a larger solid wood surface, like this Ikea countertop.

The desk is made of particleboard, and the original desktop is attached with cam lock fasteners. The cam screws go into the bottom of the desktop and engage with cam nuts in the drawer unit and side support. (General illustration of fasteners below, not indicative of how they're actually used in my desk.)

cam lock fasteners

My first thought was that I could simply screw the cam screws into the solid wood countertop and attach it to the drawers and side support the same way as the original desktop. However, it then occurred to me that I might need to account for the solid wood expanding and contracting with changes in humidity (as I understand, this isn't really a concern with particleboard).

Am I right to be concerned with wood movement? If so, how can I best attach the countertop in a way that allows it to move without damage? I've read about various ways to fasten a tabletop, but some of them don't seem appropriate - for example, anything that would require me to cut a groove in the particleboard doesn't seem like a good idea. (In general, I'm not sure what kinds of fasteners I can expect to work reliably in particleboard.)

Or would this project be inadvisable for any other reason? Is it just not worth the trouble?

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You are correct to worry about wood movement. A solid wood top it will move along it's width (in this case from the front to the back of the desk) with seasonal humidity changes. Particleboard is a stable material due to the amount of binder in it (i.e. glue) and the lack of an organized grain.

If you secure the top to the particle board without allowing for movement something will break, most likely the particleboard.

I would use "figure 8" fasteners to attach the top. These are essentially two washers joined edge-to-edge. One hole is attached to the apron (or leg in this case) and the other is attached to the underside of the tabletop. They can then pivot as the top expands and contracts.

Due to the unstable nature of particle board you'll want to use a screw that is bigger than you'd normally use for wood, both in length and diameter. You'll also need to drill a pilot hole that is slightly deeper than the screw and about 85% of the screw's outside diameter.

  • Something to watch out for, you probably can't screw directly into the "end grain" of the particleboard, it has little to no strength in that direction (one of the reasons for the cam-lock fasteners). – ench Dec 16 '16 at 20:23
  • Good point, I'll edit my answer to add a little more info about fasteners – SaSSafraS1232 Dec 16 '16 at 21:40
  • @ench There are screws specifically designed to allow this. Over here "chipboard screws" are very common and hold well, but the quality of the particleboard/chipboard is an important factor, since some is much coarser and open-textured than others, which are finer and denser. – Graphus Dec 17 '16 at 9:26
  • @Graphus Even with proper self-tapping screws, there still isn't any holding power when screwing into the edge of the board. If attaching to the "face" I agree that the proper type of screw will hold fine. – ench Dec 20 '16 at 21:50
  • @ench While it's extremely common advice these days to never drive screws into the edges of chipboard (ply too according to some) it can and is done. But as I said board and screw type matter. Even with run-of-the-mill board with quite an open texture there are a few simple tricks to increase holding power. One of the simplest is coating the screws in wood glue and it can be surprisingly effective. – Graphus Dec 21 '16 at 2:49

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