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EnglandStructural alterations and knock-throughs

Structural alterations and knock-throughs in Hampshire

Our structural alteration service covers Hampshire, including Southampton, Portsmouth and Basingstoke. You deal with one company from the first visit to the completion certificate.

Guide price in Hampshire

£5,000–£10,500 for a typical knock-through with steel beam

In Hampshire, a structural alteration typically costs £5,000–£10,500 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 Hampshire?

In Hampshire, a structural alteration typically costs £5,000–£10,500 for a typical knock-through with steel beam, including VAT at 20% (standard rate). Building costs in the South East run about 12% above the UK average, and the figures for Hampshire are adjusted to reflect that. Design, structural calculations and council fees are extra.

Guide prices for Hampshire, including VAT at 20% (standard rate)
Size or typeGuide range
A typical knock-through with steel beam£5,000–£10,500
Higher specification£10,500–£13,000

The biggest cost drivers are:

  • What sits above the wall
  • Party wall involvement
  • Moving radiators, sockets and pipes
  • 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 Hampshire?

Here is how the rules work for a structural alteration 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.

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:

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

How long does it take?

Build time is typically 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 Hampshire

Commuter towns across the South East have many 1930s and post-war semis that suit rear extensions and hip-to-gable loft conversions.

Towns we cover in Hampshire include Southampton, Portsmouth, Basingstoke, Gosport, Waterlooville and Farnborough.

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

    Permissions sorted

    Applications, building control and neighbour arrangements, all before the start date.

  4. 04

    Construction and completion

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

Questions about structural alterations in Hampshire

How much does a structural alteration cost in Hampshire?

In Hampshire, a structural alteration typically costs £5,000–£10,500 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.

Do you build structural alterations in Hampshire?

Yes. We build structural alterations across Hampshire, including postcodes BH23, BH24, BH25, GU10 and GU11. Every project starts with a free home visit.

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 long does a knock-through take?

Usually 1 to 2 weeks on site, plus a few days for plastering to dry.

Ready to talk about a structural alteration in Hampshire? Book a free home visit or get an instant guide price.

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

Call 0800 088 6248Get a guide price