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 Wiltshire?
In Wiltshire, a structural alteration typically costs £4,500–£9,750 for a typical knock-through with steel beam, including VAT at 20% (standard rate). Building costs in the South West are close to the UK average, so the figures for Wiltshire are close to our national guide. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| A typical knock-through with steel beam | £4,500–£9,750 |
| Higher specification | £9,750–£12,000 |
What moves the price most:
- Floor and ceiling repairs
- Moving radiators, sockets and pipes
- Span of the opening
- 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 Wiltshire?
The approval route for Wiltshire 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.
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
- Making good, plastering and flooring repairs
- Building control sign-off
- Steel beam supply and installation on padstones
- Building control application
- Fire protection to the steel
How long does it take?
Allow 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 Wiltshire
The South West mixes stone and render cottages with post-war and newer estates, and local materials matter more here when matching an extension.
Towns we cover in Wiltshire include Swindon, Salisbury, Trowbridge, Chippenham and Melksham.
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
Permissions sorted
Applications, building control and neighbour arrangements, all before the start date.
- 04
Build and handover
Work follows the agreed programme, with inspections along the way and a completion certificate at the end.
Questions about structural alterations in Wiltshire
Do I need a party wall notice?
In England and Wales, if the beam sits in a party wall, yes.
How much does a structural alteration cost in Wiltshire?
In Wiltshire, a structural alteration typically costs £4,500–£9,750 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 building regulations approval?
Yes. Removing a load-bearing wall is building work that needs approval, with calculations for the beam.
Do you build structural alterations in Wiltshire?
Yes. We build structural alterations across Wiltshire, including postcodes BA12, BA13, BA14, BA15 and RG17. 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.
