I have a 1905 terrace with a loft area of around 13 ft square. Loads of head height up there! The joist situation looks a bit on the light side though, with only two joists actually spanning between the two boundary walls (and which don't seem to be sitting above supporting walls). Between these two hefty joists (at least 6" thick) are attached smaller ceiling joists (about 4" thick) at 2 ft intervals.
Given the above, even if I just want to shove a couple of dozen boxes up there I am a little worried that there is not a lot of strength. Who knows what the future might be, and we may want to properly convert this space in a few years, so I was thinking of putting in a proper floor now. Can anyone hint at what this might involve / cost to do DIY-style? I can see the only real extra cost being in the new joists. Do I need an engineer/architect to design it?
Am I in danger of doing it now and the regs changing in a few years, rendering my work obsolete? Will I need to get a building control officer in now?