On Wednesday, October 17, 2012 9:57:32 PM UTC+1, Tim Watts wrote:
wrote:



On Wednesday, October 17, 2012 11:49:06 AM UTC+1, GMM wrote:



I have to build a floor in a loft. At first this will provide a platform

for some roof timber repairs to be carried out but ultimately it will be

used for storage, not living space, so there are no formal BR

requirements but, of course, I’d like it to be robust enough that it

doesn’t all wind up in the bedroom below.



At present, there is a lath and plaster ceiling, with rather

wimpy-looking ceiling joists, so not the most

stable platform to work on. It’s in pretty good condition (as a ceiling,

not a floor) so I’d like to keep it



2x8 joists is unusually large for loft storage. Almost all old joists are

quite able to handle storage. So I wonder if you've fully and correctly

evaluated the situation, ie what the current joist dimensions are (all 3).





NT



Did the OP ever say exactly what his current joists were?




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.