Flooring an attic

[coylumbridge]

I want to put a floor down in our loft using 2400mm x 600mm T&G 18mm flooring grade chipboard. It would still be accessed by a pull down ladder but would be for occasional use, eg by the kids, storage etc.

Joists span about 13'/4m from house front to centre then the same again from centre to house back. Not roof trusses - house is over 50 years old. Joists are at about 450mm centres and are 5"/125mm x 2"/50mm.

I found some details which suggest that 8" x 2" is needed for a 13' span at 450mm centres. Trouble is I only want it for occasional light use and storage.

Wondered if I can get away with just flooring the 5"x2" as at present or could I bolt some new joists on to the existing joists to strengthen them but still no more than 5" high or do I need to add in a set of new joists at 8" ?

Any ideas please ?

Thanks

 

[noseall]

most people are aware that roof timbers are inadequate and are not suitable for habitable loading, but like myself, still cram stuff into the loft regardless.

provided you don't go and remove all the upstairs partitions, and distribute the loads effectively i.e over first floor partitions, then you should have no problems regards ceilings cracking.

18mm t&g flooring will be adequate but is prone to squeaking.

it is how you deal with the 270mm of insulation that throws up questions