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Greater LondonStructural alterations and knock-throughs

Structural alterations and knock-throughs in Chiswick

Looking for a builder for a structural alteration in Chiswick? We design and build structural alterations across Greater London, covering postcodes such as W4.

Guide price in Chiswick

£5,750–£12,500 for a typical knock-through with steel beam

In Chiswick, a structural alteration typically costs £5,750–£12,500 for a typical knock-through with steel beam, including VAT at 20% (standard rate).

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Tell us about your project. We reply to arrange a visit and a fixed quote.

Free home visit and measured survey
Fixed price for the agreed specification
Drawings, approvals and build in one contract
Building control sign-off arranged
England, Wales, Scotland and Northern Ireland

What is a structural alteration?

Steel beam installed across a wide opening with props in place during a knock-through

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 Chiswick?

In Chiswick, 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.

Guide prices for Chiswick, including VAT at 20% (standard rate)
Size or typeGuide range
A typical knock-through with steel beam£5,750–£12,500
Higher specification£12,500–£15,500

Your quote will depend mainly on:

  • Party wall involvement
  • Flush or downstand beam
  • Span of the opening
  • What sits above the wall

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 Chiswick?

Approvals for a structural alteration in Chiswick 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

Handled as part of most structural alterations:

  • Fire protection to the steel
  • Temporary propping
  • Building control sign-off
  • Building control application
  • Steel beam supply and installation on padstones
  • Party wall notices where needed

How long does it take?

Expect 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 Chiswick

Space is at a premium in London, so homeowners often build out into the side return or up into the roof rather than move.

Projects in Chiswick (W4) are surveyed in person before we quote, so the price reflects your actual property.

How it works

  1. 01

    Free visit

    We look at the property, talk through what you want and measure up. There is no charge and no obligation.

  2. 02

    Drawings and written quote

    We prepare the design and give you a written, itemised quote with inclusions and exclusions.

  3. 03

    Approvals

    Planning or permitted development confirmation, building regulations and any party wall matters.

  4. 04

    Construction and completion

    We build, put right any snags and hand over the building control certificate.

Questions about structural alterations in Chiswick

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 Chiswick?

In Chiswick, 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.

Do I need building regulations approval?

Yes. Removing a load-bearing wall is building work that needs approval, with calculations for the beam.

Who approves a structural alteration in Chiswick?

Planning matters in Chiswick go to the council covering your address, and the work needs building control approval. We prepare and submit the applications for you.

Can the beam be hidden?

Often, by setting it within the ceiling depth. It depends on the joists and span.

Tell us about your project in Chiswick and we will arrange a free home visit.

Call 0800 088 6248 or get an instant guide price online.

Call 0800 088 6248Get a guide price