The Natural Philosopher wrote:
mark wrote:

Isn't mdf basically a kind of chipboard? I thought that stuff would
warp like a bannana with a bit of moisture?

Or are we talking something else more solid?

MDF once painted is dimensionally stable since it has no grain. It does
shrink and expand a little, but it seems to be uniform - so you may get
a shrinkage crack but never a warp.

But it's definitely susceptible to permamant damage like chipboard, on
exposure to water - it swells up in the same way. (I have a window
which leaked over time, resulting in a bump in the middle of the MDF
windowboard - although it was painted, the water penetrated underneath)

David