IMM wrote:

The down side of doing this is you now have a point of contact between
the floor and ceiling joists.


If the existing joists are only holding up the ceiling in the extension,
then they don't need strutting.

Actually they do (or did in our case) - for two reasons: Firstly if you
remove them then chances are you will sustain damage to the ceiling
below - because they will sag over time (even with the ties they had
already sagged a couple of inches in the centre of the span over the years.

Secondly, the BCO would insist they were there, are hence would not pass
the floor structure without.

If the existing joists were short enough (under 3m say) you may then get
away with removing the ties.


--
Cheers,

John.

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