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 Dorset?
In Dorset, a structural alteration typically costs £4,500–£9,750 for a typical knock-through with steel beam, including VAT at 20% (standard rate). Prices in the South West sit near the national average for this kind of work, and the range for Dorset reflects that. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| A typical knock-through with steel beam | £4,500–£9,750 |
| Higher specification | £9,750–£12,000 |
What moves the price most:
- What sits above the wall
- Flush or downstand beam
- Floor and ceiling repairs
- Party wall involvement
For a figure based on your own measurements, try the guide price tool, then book a free home visit for a fixed quote.
Do you need planning permission for a structural alteration in Dorset?
The approval route for Dorset 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.
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.
We check this for your address before design work starts, so there are no surprises later.
What we handle
The work we manage on a structural alteration:
- Steel beam supply and installation on padstones
- Building control sign-off
- Building control application
- Temporary propping
- Party wall notices where needed
- Structural engineer’s calculations and drawings
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 Dorset
In parts of the South West, protected landscapes and conservation areas shape what can be built, so materials and roof forms are chosen carefully.
Towns we cover in Dorset include Bournemouth, Poole, Weymouth and Christchurch.
How it works
- 01
Survey and brief
We visit, discuss your ideas and budget, and survey the property or site at no cost.
- 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
Build and handover
Work follows the agreed programme, with inspections along the way and a completion certificate at the end.
Questions about structural alterations in Dorset
Can the beam be hidden?
Often, by setting it within the ceiling depth. It depends on the joists and span.
Do you build structural alterations in Dorset?
Yes. We build structural alterations across Dorset, including postcodes BA22, BH1, BH10, BH11 and BH12. Every project starts with a free home visit.
Do I need building regulations approval?
Yes. Removing a load-bearing wall is building work that needs approval, with calculations for the beam.
How much does a structural alteration cost in Dorset?
In Dorset, a structural alteration typically costs £4,500–£9,750 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.