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 Christchurch?
In Christchurch, a structural alteration typically costs £4,500–£9,750 for a typical knock-through with steel beam, including VAT at 20% (standard rate). Prices in the South West sit near the national average for this kind of work, and the range for Christchurch reflects that. 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 |
The biggest cost drivers are:
- Span of the opening
- Party wall involvement
- Flush or downstand beam
- Moving radiators, sockets and pipes
Your exact price depends on the survey and drawings. The guide price tool gives a quick range in the meantime.
Do you need planning permission for a structural alteration in Christchurch?
Before anything is built in Christchurch, we confirm which approvals apply 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.
Where work involves a shared wall, building on the boundary, or digging foundations within 3 metres of a neighbour’s building and deeper than its foundations (or within 6 metres for deeper work), the Party Wall etc. Act 1996 applies and notices must be served before work starts.
Our first visit includes a check of your planning history, so you know the route before paying for drawings.
What we handle
The work we manage on a structural alteration:
- Temporary propping
- Structural engineer’s calculations and drawings
- Building control application
- Steel beam supply and installation on padstones
- Building control sign-off
- Party wall notices where needed
How long does it take?
Expect 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 Christchurch
The South West mixes stone and render cottages with post-war and newer estates, and local materials matter more here when matching an extension.
Projects in Christchurch (BH23) are surveyed in person before we quote, so the price reflects your actual property.
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
Construction and completion
We build, put right any snags and hand over the building control certificate.
Questions about structural alterations in Christchurch
How much does a structural alteration cost in Christchurch?
In Christchurch, 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 a party wall notice?
In England and Wales, if the beam sits in a party wall, yes.
Do you build structural alterations in Christchurch?
Yes. We build structural alterations across Christchurch, including postcodes BH23. 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.
How long does a knock-through take?
Usually 1 to 2 weeks on site, plus a few days for plastering to dry.
