You need structural calculations whenever building work changes how loads travel through your home and someone has to show that the result is safe. Part A of the Building Regulations covers structure, and building control will want evidence that your design complies.
Work That Usually Needs Them
- Removing a load-bearing wall: the most common reason, because a beam has to carry what the wall carried.
- Opening up the back of a house: bi-fold doors or a wider opening mean a new beam over the gap.
- Extensions with steels: especially where the new room opens into the existing house.
- Loft conversions: new floor joists, steels and support for the altered roof.
- Removing a chimney breast: anything left above needs proper support.
What the Calculations Have to Prove
When a load-bearing wall comes out, the load above it still has to reach the ground. The calculations show that the beam, its supports and what sits beneath them can safely carry it.
What About a Wall That Isn't Load-bearing?
Don't assume. Stud walls can still carry loads, and a thin wall can be supporting a floor above. An engineer should confirm it before anything comes down.
What Building Control Looks For
- The loads the structure has to carry
- The size and grade of each beam or member
- How the beam is supported at each end, including padstones and bearing lengths
- Connections, and how the steel will meet fire protection requirements
- Foundations, where new loads reach the ground
Requirements vary with the job, so ask your building control body what it needs for yours.
Do It Before You Get Builders' Quotes
Beam sizes affect cost, ceiling lines and access. Having calculations first means builders price the same job, and you avoid changes once work has started.
We produce calculations in-house. A wall removal or single steel beam starts at £295. See structural calculations.