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 Sidcup?
In Sidcup, a structural alteration typically costs £5,750–£12,500 for a typical knock-through with steel beam, including VAT at 20% (standard rate). Building costs in London run about 30% above the UK average, and the figures for Sidcup are adjusted to reflect that. 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:
- Flush or downstand beam
- What sits above the wall
- Party wall involvement
- Moving radiators, sockets and pipes
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 Sidcup?
Approvals for a structural alteration in Sidcup follow the rules for 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
What we take care of:
- Fire protection to the steel
- Making good, plastering and flooring repairs
- Building control sign-off
- Building control application
- Steel beam supply and installation on padstones
- Temporary propping
How long does it take?
Build time is typically 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 Sidcup
Many London boroughs have conservation areas and detailed design guides, so early design advice saves time at the planning stage.
If your home is in Sidcup or close by in Welling, Eltham and Bexleyheath, a free home visit is the first step.
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 pricing
Design options, then a fixed quote based on the chosen drawings and specification.
- 03
Approvals in place
We handle planning, building control and neighbour notices before work starts.
- 04
Build and sign-off
We run the build to a written programme and hand over the completion certificate.
Questions about structural alterations in Sidcup
How long does a structural alteration take in Sidcup?
Typically 1 to 2 weeks on site for a typical knock-through. Design and approvals beforehand usually take 6 to 12 weeks.
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 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 Sidcup?
In Sidcup, 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.