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 Clapham?
In Clapham, a structural alteration typically costs £5,750–£12,500 for a typical knock-through with steel beam, including VAT at 20% (standard rate). The guide for Clapham reflects typical costs in London, roughly 30% above the UK-wide figure. 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:
- Span of the opening
- Party wall involvement
- Floor and ceiling repairs
- Flush or downstand beam
For a figure based on your own measurements, try the guide price tool, then book a free home visit for a fixed quote.
Do you need planning permission for a structural alteration in Clapham?
The approval route for Clapham is set by planning law 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.
We check this for your address before design work starts, so there are no surprises later.
What we handle
The work we manage on a structural alteration:
- Building control sign-off
- Temporary propping
- Making good, plastering and flooring repairs
- Steel beam supply and installation on padstones
- Fire protection to the steel
- Party wall notices where needed
How long does it take?
The build itself usually takes 1 to 2 weeks on site for a typical knock-through. Before that, surveys, drawings and approvals usually take 6 to 12 weeks, longer if the council asks for changes.
Building in Clapham
Space is at a premium in London, so homeowners often build out into the side return or up into the roof rather than move.
From SW4 outwards, we take on projects throughout Clapham and the surrounding parts of Greater London.
How it works
- 01
Free visit
We look at the property, talk through what you want and measure up. There is no charge and no obligation.
- 02
Drawings and written quote
We prepare the design and give you a written, itemised quote with inclusions and exclusions.
- 03
Approvals
Planning or permitted development confirmation, building regulations and any party wall matters.
- 04
Construction and completion
We build, put right any snags and hand over the building control certificate.
Questions about structural alterations in Clapham
Can the beam be hidden?
Often, by setting it within the ceiling depth. It depends on the joists and span.
Do you build structural alterations in Clapham?
Yes. We build structural alterations across Clapham, including postcodes SW4. Every project starts with a free home visit.
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.
How much does a structural alteration cost in Clapham?
In Clapham, 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.
Do I need a party wall notice?
In England and Wales, if the beam sits in a party wall, yes.