Steve wrote:

Thanks for that Tony. I will download the demo and have a play with
various options.

I just did a quick calc in SB with a 1.3m 4x2" beam. Assuming a uniform
floor load of 0.8kN per joist, plus a worst case point load in the
middle of the span of 1.6kN (i.e. one piano leg), your current floor
fails to meet the spec in bending and deflection - but not by a huge
margin. Doubling up the exiting joists with another the same size sat
beside it (and nailed too it would probably be simplest at that size),
seems to make it stiff enough.

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/