As part of or building work, we need a steel lintel across where a set of French doors and an enlarged doorway to the kitchen. Our builder has said he can measure and make t no problem, but that to get it approved for building regs he should get it checked and have a plan drawn up by an architectural/structural engineer. His guy charges for £550. Our builder suggests this is optional/doable if and when we sell the house.
Is he right? What would the pitfalls of doing it like this be? Is this price normal?