In article ,
"brugnospamsia" says...
Dear group,

I have lived in my "first time buyer" terraced house for 21 years and can't
see myself "upgrading" in the forseeable future.

Having had the roof rebuilt, the 140 year old upstairs ceilings were shot
and I found it made sense to completely replace them with new timbers and
foil-backed plasterboard.

I am now faced with two non-level, bouncy and bendy upstairs floors and
given that the downstairs ceilings also need replacing, I am wondering if
this is the best solution here too. The under-spec. joists run front to back
and are (loosely) cemented in to the outside and stairwell walls so the
replacement joists would have to be attached to wallplates and hangers. I
plan to use 22mm t&g chipboard in anticipation that most buyers in my area
tend to want carpet or laminate upstairs rather than sanded boards (I plan
to have carpet upstairs and sanded boards downstairs).

Having lived in the street so long, my observations make me doubt any of the
other houses have had so much trouble expended on them ...

Am I completely barking ?

Not if you're doing the work yourself and you're going to be living
there for a while - you want it good to use, you're not after quick
profit from resale. I'd be inclined to investigate the possibility
of replacing the joists without using hangers though - is it out of
the question to cut through one of the supporting walls so that the
joists could be slid into place?