On 26/04/2020 13:57, Roland Perry wrote:
In message , at 13:40:25 on Sun, 26 Apr
2020, Andrew remarked:

He hasn't told us what the gap is above this false ceiling. does
it need a smoke detector ?.

Eight inches. It's to disguise an RSJ, which I'm told will be itself be
cased in fireproof board at some stage.

Well you could rest one end of the 3x2's on the flange of the RSJ,
and hammer/wedge a strip of timber on top of the 3x2's lengthwise
along the RSJ such that the wedge is a tight fit into the gap between
the top of the 3x2 and the upper flange of the rsj, ...

leaving you to support the other end,..

However, BCO might raise objections to this approach.