Thank you for the replies.
These joists are also in the loft space, and there are two steps down into this room. I think the house originally had a single story extension - and this room has been added on top, so originally they could have been ceiling/loft joists?
I'll post to the...
Hi - I've been using the forum for all sorts of research and have found it very helpful.
Whilst decorating a room I wanted to add a network point and a phone point and was going to notch one joist and drill through the others using this information:
http://niceic.com/Uploads/File3777.pdf...