SK Developments Free home visit0800 088 6248 Get a quote

CambridgeshireStructural alterations and knock-throughs

Structural alterations and knock-throughs in Cambridge

Looking for a builder for a structural alteration in Cambridge? We design and build structural alterations across Cambridgeshire, covering postcodes such as CB5, CB21, CB22 and CB23.

Guide price in Cambridge

£4,750–£10,000 for a typical knock-through with steel beam

In Cambridge, a structural alteration typically costs £4,750–£10,000 for a typical knock-through with steel beam, including VAT at 20% (standard rate).

Book a free home visit

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 Cambridge?

In Cambridge, a structural alteration typically costs £4,750–£10,000 for a typical knock-through with steel beam, including VAT at 20% (standard rate). That range is adjusted for the East of England, where domestic building work typically costs around 6% above the national average. Design, structural calculations and council fees are extra.

Guide prices for Cambridge, including VAT at 20% (standard rate)
Size or typeGuide range
A typical knock-through with steel beam£4,750–£10,000
Higher specification£10,000–£12,500

What moves the price most:

  • Span of the opening
  • What sits above the wall
  • Moving radiators, sockets and pipes
  • Flush or downstand beam

Use the guide price tool to see how size and specification change the figure, then ask for a written, itemised quote.

Do you need planning permission for a structural alteration in Cambridge?

The approval route for Cambridge is set by planning law 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.

At the survey we check your house’s planning history and any restrictions, and tell you which route applies.

What we handle

Handled as part of most structural alterations:

  • Making good, plastering and flooring repairs
  • Party wall notices where needed
  • Structural engineer’s calculations and drawings
  • Building control sign-off
  • Steel beam supply and installation on padstones
  • Fire protection to the steel

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 Cambridge

Many towns in the East of England have estates built since the 1970s, where garage conversions and rear extensions are popular.

Cambridge sits in Cambridgeshire. We cover the whole of Cambridge, including postcodes CB5, CB21, CB22 and CB23.

How it works

  1. 01

    Survey and brief

    We visit, discuss your ideas and budget, and survey the property or site at no cost.

  2. 02

    Design and fixed quote

    Drawings, structural calculations and an itemised, fixed price for the agreed specification.

  3. 03

    Approvals

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

  4. 04

    Build and sign-off

    We run the build to a written programme and hand over the completion certificate.

Questions about structural alterations in Cambridge

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 Cambridge?

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

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 Cambridge?

In Cambridge, a structural alteration typically costs £4,750–£10,000 for a typical knock-through with steel beam, including VAT at 20% (standard rate). Your fixed price depends on the survey and drawings.

Can the beam be hidden?

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

Start with a guide price, then book a free survey for a fixed quote in Cambridge.

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

Call 0800 088 6248Get a guide price