Loft floor supporting beam

[EdwardianMonster]

I found the sites detailing required sizes of floor joists for MxM size of rooms; but is there similar for supporting these beams in the middle, as in front to back of house is 7m, floor joists are each 4m and meet across a central beam in the middle where the width is 4m.

So width 4m, length 7m divided in two by a supporting beam.
(Which currently is wooden about 6x4, as part of the dividing wall downstairs)

 

[tony1851]

Why do you need a middle beam if you've already got a dividing wall there, or have I misunderstood?

 

[EdwardianMonster]

The dividing wall on the floor below seems to be mainly hollow, plaster & lathe. The beam in question seems original part of that wall.
There might be structural vertical support to the beam hidden in the wall, its edwardian I dont know if they did that. But basically I think the front and back loft floor joists are relying on that beam.

 

[tony1851]

As well as that 6x4 beam, some of the load is presumably transmitted to whatever is supporting the partition, via the studwork.