Structural calculations for a steel beam start at from £425 with us. No council fee applies, because building control checks the pack as part of your building regulations approval, and it charges for that check separately.
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The price is a floor because jobs differ: one beam over a kitchen opening is a short pack, and a loft conversion with several steels, a new floor and a dormer is a longer one. We confirm the total in writing before the engineer starts, so nothing grows quietly.
What are you actually buying?
A set of numbers a building control officer can follow, and a beam size a builder can order. The pack traces the loads from the roof and floors above down to the opening, selects a steel section and grade that carries them within the allowed deflection, and sizes the padstones that spread the load into the wall beneath.
The legal basis is Part A of Schedule 1 to the Building Regulations 2010: A1 loading, A2 ground movement and A3 disproportionate collapse (Schedule 1). Regulation 4 says building work must comply with them (regulation 4), and that is why an officer will ask for the figures before the wall comes out. For steel members, Approved Document A points to BS EN 1993-1-1 (Approved Document A).
When do you need them?
Whenever a load-bearing wall is removed or opened up. The four common cases in London houses are an open-plan knock-through, the opening between an old house and a new rear extension, a loft conversion with new floor joists and steels, and a dormer that cuts the rafters. Our Part A guide goes through each.
Not every wall is load-bearing, and not every opening needs steel. A short lintel over a door in a single-storey extension may need only a schedule. We say so when that is true of yours, and we would rather you did not buy a pack you do not need.
What do you pay on top of our fee?
Three things sit outside it:
- Building control's charge, paid to your council or the registered approver you choose (GOV.UK). Ask for quotes.
- The steel and the builder's work, which the calculation sizes but does not price.
- Party wall costs, if the beam bears on a shared wall.
On that last point, cutting into a party structure needs notice at least two months before work begins (section 3), and a neighbour who does not consent in writing within fourteen days is deemed to dissent (section 5). Party wall services are not ours. We give your party wall surveyor an exact beam size, which makes agreement faster. Put the two months into your programme before a builder is booked.
Is it cheaper bought with the drawings?
When both are needed, yes: the engineer works from our drawings and one survey serves both. Our building regulations drawings are £545 drawings + £150 survey (£695 total), and bought separately the two are £1,120. If your project is permitted development, the regulations and structural bundle is £1,095, below that sum. Where you also need planning, the full package starts at £1,395. Our cost of building regulations drawings post compares the combinations.
Frequently asked questions
Who prepares the calculations? A qualified structural engineer. We draw the building regulations set to match the pack, so building control receives one coordinated submission.
Can the beam go in before the calculation is checked? The sensible order is calculation, then building control submission, then the wall. Starting first means any query is settled on site instead of on paper.
Do I need a calculation for a loft conversion beam? Yes, where steel carries new loads. The new floor joists and the beams under them belong in the same pack.
Does a calculation tell me if the wall is load-bearing? It starts from the survey and your drawings, so the wall's role is established first. If we cannot tell from those, an engineer's site visit may be needed, and we tell you before charging for it.
