In message , at 13:02:37 on Tue, 28 Apr
2020, Andrew remarked:
On 28/04/2020 12:09, Roland Perry wrote:
In message , at 11:32:46 on
Tue, 28 Apr 2020, Tim Lamb remarked:
In message , Roland Perry
writes
That's going to be an awful lot of fireproof plasterboard (although
not necessarily a bad thing). The original plan was just to box in
the RSJ, I think. And have a "step" between the two halves, but
that's going to look very odd.

Plasterboard is apparently the new toilet paper. Factories are
closed and builders merchants run out.
I have a couple of sheets put by:-)

Could you not clad the beam in enough Oak to meet the fire regs. and
call it a *feature*?
The objective is to have a flat ceiling, not one with a feature
RSJ-cladding.

So, in your addition to my 'graphics' you could trim those 6x2
joists to drop their bottom edge level with the underside of the
RSJ, unless the work is already done

They are very firmly completely above the lower flange.

in which case just run your
3x2 at 90 degrees to the 6x2 and screw the cross joints.

2 layers of 12.5 PB is usually acceptable intead of 1 layer
of 15 mm pink fireline to a BCO

Thanks.
--
Roland Perry