Fash wrote:
SNIP
Anyone done this before?
All advice (although especially good advice) welcomed.

Fash

Steel doesn't creep, so assuming that the live load hasn't changed much (and
that the beams haven't deteriorated over time and been subject to a fire
etc), then the deflection occurred when the modification was undertaken,
hence the deflection won't get worse due to the deadload - however as the
beams were installed sideways (why???) as you rightly point out the strength
has been reduced somewhat, and may deflect due to the live load (do you get
cracking in walls etc), but nevertheless given the time its been there its
unlikely to be unsafe!

You could do nothing and live with the deflection (if the live loads are
okay), however as other have pointed out you need a structural engineer and
competent builder to undertake these works as there are lots of
considerations, such as beam design, pad stones, method of works, accrow
design and location etc.. + all the consequences of jacking and moving the
up the above walls - if you plan to change the steels, warn the wife before
the quote comes in that a family holiday might be out of the question for a
good few years!

Jon