My SE has specified a steel beam 152x152x30 with 10mm plate welded to top and bottom flange. This is support a clear span of 1.8m for a patio door. In their calculations, they said the load on each bearing is 33.8kN so total load is 67.6kN.
From what l have tried to understand about how to calculate load on lintels, this seems very high. There is a window direct above the opening on the 1st floor and dormer loft above that. It’s a normal cavity wall.
Reason I am doubting all their calculations is because they also specify a steel beam 178x102x19 for a 1st floor lintel to support an opening of 1.9m. Here the load given is only 10kN so don’t understand why a concrete lintel would not suffice.
Before I go back to them (as they are slow at answering), I just wanted to get a idea if my concerns are valid or not.
From what l have tried to understand about how to calculate load on lintels, this seems very high. There is a window direct above the opening on the 1st floor and dormer loft above that. It’s a normal cavity wall.
Reason I am doubting all their calculations is because they also specify a steel beam 178x102x19 for a 1st floor lintel to support an opening of 1.9m. Here the load given is only 10kN so don’t understand why a concrete lintel would not suffice.
Before I go back to them (as they are slow at answering), I just wanted to get a idea if my concerns are valid or not.