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 Erith?
In Erith, 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 |
Your quote will depend mainly on:
- Floor and ceiling repairs
- Party wall involvement
- Flush or downstand beam
- Span of the opening
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 Erith?
Before anything is built in Erith, 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.
Our first visit includes a check of your planning history, so you know the route before paying for drawings.
What we handle
From survey to sign-off, the job normally involves:
- Making good, plastering and flooring repairs
- Steel beam supply and installation on padstones
- Building control sign-off
- Temporary propping
- Building control application
- Structural engineer’s calculations and drawings
How long does it take?
The build itself usually takes 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 Erith
Many London boroughs have conservation areas and detailed design guides, so early design advice saves time at the planning stage.
From DA8 outwards, we take on projects throughout Erith and the surrounding parts of Greater London.
How it works
- 01
Visit and measured survey
A free visit to understand the project, check access and take measurements.
- 02
Drawings and written quote
We prepare the design and give you a written, itemised quote with inclusions and exclusions.
- 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 Erith
How long does a knock-through take?
Usually 1 to 2 weeks on site, plus a few days for plastering to dry.
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 Erith?
In Erith, 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.
What fire protection does a steel need?
Usually fire-rated plasterboard or intumescent paint, as building control requires.
Who approves a structural alteration in Erith?
Planning matters in Erith go to the council covering your address, and the work needs building control approval. We prepare and submit the applications for you.