On 13/06/2020 14:04, Lee Nowell wrote:
There is a loft room above but putting ply on top of the joists will impact the floor above.

snip

So you have to allow for the weight of a person standing on top of the
suspension point too.

No doubt a single joist will take it without failing, the question is,
will it flex enough to crack plaster?

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Cheers
Clive