Steel Beam Layout for 2 Storey Extension

[scottisthename]

Hi all,

I'm working on drawings for a 2 storey extension to the rear of my house. Part of my design is to have a corner of the ground floor opening fully (2 sets of bi-fold doors), without any vertical support in the corner. The image shows the general layout and dimensions, with my idea of beam locations. I will eventually have a structural engineer on the case, but wanted to get a general plan in place. My questions are:-

1) Does this look like the most effective method of supporting the house above the open corner (other suggestions welcome)?

2) With a span of 7.6m, is this feasible?

3) Approximately what size beam would be required for a 7.6m span?

I hope that little lot makes sense.

Appreciate any feedback.

scott