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 Stanmore?
In Stanmore, a structural alteration typically costs £5,750–£12,500 for a typical knock-through with steel beam, including VAT at 20% (standard rate). That range is adjusted for London, where domestic building work typically costs around 30% above the national average. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| A typical knock-through with steel beam | £5,750–£12,500 |
| Higher specification | £12,500–£15,500 |
The biggest cost drivers are:
- Party wall involvement
- What sits above the wall
- Floor and ceiling repairs
- 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 Stanmore?
Before anything is built in Stanmore, 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.
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
On a typical structural alteration we handle:
- Structural engineer’s calculations and drawings
- Party wall notices where needed
- Steel beam supply and installation on padstones
- Making good, plastering and flooring repairs
- Building control sign-off
- Building control application
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 Stanmore
Space is at a premium in London, so homeowners often build out into the side return or up into the roof rather than move.
Our Stanmore coverage includes postcode districts HA7, and we also work in nearby places such as Edgware, Bushey and Harrow.
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 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 Stanmore
Do I need a party wall notice?
In England and Wales, if the beam sits in a party wall, yes.
What fire protection does a steel need?
Usually fire-rated plasterboard or intumescent paint, as building control requires.
How much does a structural alteration cost in Stanmore?
In Stanmore, 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.
How long does a knock-through take?
Usually 1 to 2 weeks on site, plus a few days for plastering to dry.
Who approves a structural alteration in Stanmore?
Planning matters in Stanmore go to the council covering your address, and the work needs building control approval. We prepare and submit the applications for you.
