On Wed, 16 Jun 2004 10:17:31 GMT, a particular chimpanzee named "Mark
Walters" randomly hit the keyboard
and produced :

There is a fixed staircase leading up to the room and it was certainly made
habitable before 1985.

The floor has proper fixed floorboards - the joists are 6"x2" - and appears
to be very stable. There's no obvious bounce and the lath and plaster
ceiling
of the room below has only a few minor cracks which I take to mean that
there's
not been a lot of movement.

Apologies, I didn't read the entire thread before replying. It sounds
like it was converted legally (or at least, as near as damnit to the
requirements at the time), so you only need to concern yourself with
upgrading the insulation. A building regulations application would be
required for adding a Velux window, but only for the structural work
in trimming the rafters, and to control the heat loss through the
window.