RSJ Top Plate, How Wide?

[iDIY]

Hi Guys,

I have done all the usual searches but cant find the answer to this, so i'm asking here

I have planning permission in place and an independent BCO lined up. I have a structural engineer lined up to do calculations but at present I am just wanting to price up a few major components.

So, I will have a 6m beam, spanning 5.8m supported each end on a padstone set into the inner leaf. The RSJ will support floor joists across its span but at each end of the span it will also support a 440mm return cavity wall (2.2m high)

Obviously I need to price an rsj with a top plate but my question is this and seems simple enough that I should know... If the short section of cavity wall at each end of the span are 290mm wide (100mm Block / 90mm Cavity / 100mm Block) then how wide should the top plate be? I seem to think it should be narrower than the wall but i'm not sure.

 

[^woody^]

If its just for pricing then you will just assume its the width of the wall sitting on it.

It wont be an accurate price in any case as you dont even know how thick it needs to be, the grade and likewise for the steels it is to welded to.

 

[tony1851]

A 250 wide x 6mm thick plate would be fine - an overlap of up to 25mm for either skin would be acceptable.
But your SE will probably spec something over the top, like 300 x 10.