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 Mitcham?
In Mitcham, a structural alteration typically costs £5,750–£12,500 for a typical knock-through with steel beam, including VAT at 20% (standard rate). We start from a UK-wide guide and adjust it for London, where labour and materials are typically about 30% above 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:
- Moving radiators, sockets and pipes
- Party wall involvement
- Flush or downstand beam
- Span of the opening
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 Mitcham?
Approvals for a structural alteration in Mitcham 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.
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.
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:
- Party wall notices where needed
- Building control application
- Building control sign-off
- Making good, plastering and flooring repairs
- Structural engineer’s calculations and drawings
- Fire protection to the steel
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 Mitcham
Victorian and Edwardian terraces dominate many London streets, which is why side return, wraparound and mansard projects are so common here.
We work across Mitcham and neighbouring areas such as Morden, Tooting and Wimbledon. Postcodes we cover in Mitcham include CR4.
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 fixed quote
Drawings, structural calculations and an itemised, fixed price for the agreed specification.
- 03
Permissions sorted
Applications, building control and neighbour arrangements, all before the start date.
- 04
Build and sign-off
We run the build to a written programme and hand over the completion certificate.
Questions about structural alterations in Mitcham
How much does a structural alteration cost in Mitcham?
In Mitcham, 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 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.
Do you build structural alterations in Mitcham?
Yes. We build structural alterations across Mitcham, including postcodes CR4. Every project starts with a free home visit.
How long does a knock-through take?
Usually 1 to 2 weeks on site, plus a few days for plastering to dry.
Do I need a party wall notice?
In England and Wales, if the beam sits in a party wall, yes.