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 Swanley?
In Swanley, a structural alteration typically costs £5,000–£10,500 for a typical knock-through with steel beam, including VAT at 20% (standard rate). That range is adjusted for the South East, where domestic building work typically costs around 12% above the national average. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| A typical knock-through with steel beam | £5,000–£10,500 |
| Higher specification | £10,500–£13,000 |
The biggest cost drivers are:
- Moving radiators, sockets and pipes
- Party wall involvement
- Flush or downstand beam
- What sits above the wall
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 Swanley?
Approvals for a structural alteration in Swanley 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.
Our first visit includes a check of your planning history, so you know the route before paying for drawings.
What we handle
Handled as part of most structural alterations:
- Structural engineer’s calculations and drawings
- Temporary propping
- Fire protection to the steel
- Party wall notices where needed
- Steel beam supply and installation on padstones
- Building control application
How long does it take?
Allow 1 to 2 weeks on site for a typical knock-through. Allow time beforehand for drawings and approvals, usually 6 to 12 weeks.
Building in Swanley
The South East has a broad mix of housing, from Victorian terraces in the towns to post-war semis and newer estates, so extension types vary street by street.
Swanley sits in Kent, about 17 miles north-west of Maidstone. We cover the whole of Swanley, including postcodes BR8.
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
Design and pricing
Design options, then a fixed quote based on the chosen drawings and specification.
- 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 Swanley
How much does a structural alteration cost in Swanley?
In Swanley, a structural alteration typically costs £5,000–£10,500 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 knock-through take?
Usually 1 to 2 weeks on site, plus a few days for plastering to dry.
Do you build structural alterations in Swanley?
Yes. We build structural alterations across Swanley, including postcodes BR8. Every project starts with a free home visit.
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.
