In message , Tim Lamb
writes
In message , Stuart
writes

I had exactly the same thing on our church kitchen floor. The fix was to
cut some narrow slots across the join with a router about 75mm long and
12mm deep. Then drop a suitable dowel (I just used plated wood screws)
in each slot and fill with fibreglass resin. This effectively stitches
the two ends together - no further movement.

It worked!

At least it looked OK yesterday evening:-)

The dowels were 6mm plated roofing bolts with the heads removed.

Issues arising. Scattering saw dust on a sticky floor, failure to
realise how much resin would be needed (old chipboard is like blotting
paper) and not anticipating that resin is thin enough to flow through
tiny cracks.

I look forward to some future make-over program unearthing this patch
and discussing the parentage of the perpetrators:-)

Regards to all who contributed

--
Tim Lamb