On 22 Mar 2004 06:14:22 -0800, a particular chimpanzee named
(P Lavers) randomly hit the keyboard and
produced:

Anyone know what differences there are in the building regulations
applicable to loft conversions between those for an existing 2 story
house (with which I am familiar) as apposed to an existing 3 story
house? In particular fire regulations with respect to the stairwell
and doors leading off it. I have a house with a basement kitchen and
am considering a loft conversion which would make the house 4 floors
in all.

To some extent it depends on the height of the top floor above the
lowest ground level.

If the basement is a true basement (not a lower ground floor with a
difference in levels between the front and the back) then it would
still be counted as an existing two storey house. There is nothing
stated in AD 'B', but if the basement is accessed from the hall, then
the existing door could be retained if fitted with a self closer.

If the top floor is more than 7.5m above the lowest ground level, then
it will be treated as though it is a new four storey dwelling. An
alternative escape (a fixed stair or other escape route, not just an
opening window) will be required from the third floor, and the
existing stair will need to be enclosed in 30 mins fire resistance and
fire doors from top to bottom. Speak to your Building Control
section. They may be prepared to accept other measures instead of an
alternative stair from the top floor such as a higher standard of
detection or a sprinkler system.
--
Hugo Nebula
"The fact that no-one on the internet wants a piece of this
shows you just how far you've strayed from the pack".