On Thursday, October 18, 2012 5:56:35 PM UTC+1, Alan Braggins wrote:
In article , GB wrote:



The simple answer is there aren't any - apart from the skinny (3x2 or so) ceiling joists. Since these are 150 years old, I wouldn't walk on them without care, let alone base any kind of structure on them.



You'll be walking on those when you do the work. Will you support them

temporarily?



He said he was thinking of boards on Acro props. Knowing exactly which bits

are supported from below when working above might be a bit tricky, but at the

least they'll effectively have a much shorter span.

Quite straightforward really: The loft is exactly the same as the room beneath, so props can be put
directly under the points where work is taking place and moved as it progresses. Using boards above
and below will spread the load.
As you say, even off (but close to) a board this will effectively shorten the span of timber so reduce stresses.
Certainly, in my view, preferable to buggering up the ceiling.