What is a structural alteration?

A structural alteration changes how a house carries its loads, most often by removing a load-bearing wall and replacing it with a steel beam. It is how kitchens and dining rooms become open-plan, and how extensions are joined to the original house.
How much does a structural alteration cost in Brixton?
In Brixton, a structural alteration typically costs £5,750–£12,500 for a typical knock-through with steel beam, including VAT at 20% (standard rate). Prices across London are typically 30% above the UK average for this kind of work, which is reflected in the range for Brixton. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| A typical knock-through with steel beam | £5,750–£12,500 |
| Higher specification | £12,500–£15,500 |
The main things that change the cost:
- Floor and ceiling repairs
- Flush or downstand beam
- What sits above the wall
- Party wall involvement
A guide range is only a starting point: the guide price tool gives an instant figure for your size, and a free survey turns it into a fixed quote.
Do you need planning permission for a structural alteration in Brixton?
Here is how the rules work for a structural alteration in England. In England removing a load-bearing wall does not need planning permission but does need building regulations approval with an engineer’s calculations. If the beam bears on a party wall, a party wall notice must be served.
Building regulations approval comes from the council’s building control service or a registered building control approver. The work is inspected at key stages, such as foundations, drainage and insulation, and a completion certificate is issued at the end.
At the survey we check your house’s planning history and any restrictions, and tell you which route applies.
What we handle
The work we manage on a structural alteration:
- Structural engineer’s calculations and drawings
- Party wall notices where needed
- Fire protection to the steel
- Building control application
- Temporary propping
- Steel beam supply and installation on padstones
How long does it take?
Allow 1 to 2 weeks on site for a typical knock-through. Design and approvals come first and typically take 6 to 12 weeks, depending on the approval route.
Building in Brixton
Victorian and Edwardian terraces dominate many London streets, which is why side return, wraparound and mansard projects are so common here.
We work across Brixton and neighbouring areas such as Clapham, Dulwich and Peckham. Postcodes we cover in Brixton include SW2.
How it works
- 01
Survey and brief
We visit, discuss your ideas and budget, and survey the property or site at no cost.
- 02
Design and fixed quote
Drawings, structural calculations and an itemised, fixed price for the agreed specification.
- 03
Permissions sorted
Applications, building control and neighbour arrangements, all before the start date.
- 04
Build and sign-off
We run the build to a written programme and hand over the completion certificate.
Questions about structural alterations in Brixton
How do I know if a wall is load-bearing?
Only a survey can confirm it. Walls that carry floor joists, roof loads or walls above are load-bearing. We check on site and the engineer confirms.
What fire protection does a steel need?
Usually fire-rated plasterboard or intumescent paint, as building control requires.
Can the beam be hidden?
Often, by setting it within the ceiling depth. It depends on the joists and span.
How much does a structural alteration cost in Brixton?
In Brixton, a structural alteration typically costs £5,750–£12,500 for a typical knock-through with steel beam, including VAT at 20% (standard rate). Your fixed price depends on the survey and drawings.
How long does a structural alteration take in Brixton?
Typically 1 to 2 weeks on site for a typical knock-through. Design and approvals beforehand usually take 6 to 12 weeks.
