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 West Glamorgan?
In West Glamorgan, a structural alteration typically costs £4,250–£8,750 for a typical knock-through with steel beam, including VAT at 20% (standard rate). The guide for West Glamorgan reflects typical costs in Wales, roughly 8% below the UK-wide figure. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| A typical knock-through with steel beam | £4,250–£8,750 |
| Higher specification | £8,750–£11,000 |
What moves the price most:
- Floor and ceiling repairs
- Moving radiators, sockets and pipes
- Party wall involvement
- 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 West Glamorgan?
Before anything is built in West Glamorgan, we confirm which approvals apply in Wales. In Wales removing a load-bearing wall needs building regulations approval with structural calculations, and party wall notices where a shared wall is involved.
Building regulations in Wales are set by the Welsh Government. Approval comes from the council’s building control service or a registered building control approver, with inspections during the work and a completion certificate at the end.
If the answer is not clear-cut, we can apply for formal confirmation before you commit to the build.
What we handle
The work we manage on a structural alteration:
- Structural engineer’s calculations and drawings
- Steel beam supply and installation on padstones
- Fire protection to the steel
- Party wall notices where needed
- Temporary propping
- Making good, plastering and flooring repairs
How long does it take?
The build itself usually takes 1 to 2 weeks on site for a typical knock-through. Design and approvals come first and typically take 6 to 12 weeks, depending on the approval route.
Building in West Glamorgan
Wales has many terraced valley streets, stone cottages and post-war estates, so extension designs are shaped by slopes, materials and local character.
Towns we cover in West Glamorgan include Swansea, Neath, Gorseinon and Clydach.
How it works
- 01
Survey and brief
We visit, discuss your ideas and budget, and survey the property or site at no cost.
- 02
Design and pricing
Design options, then a fixed quote based on the chosen drawings and 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 West Glamorgan
How much does a structural alteration cost in West Glamorgan?
In West Glamorgan, a structural alteration typically costs £4,250–£8,750 for a typical knock-through with steel beam, including VAT at 20% (standard rate). Your fixed price depends on the survey and drawings.
Who approves a structural alteration in West Glamorgan?
Planning matters in West Glamorgan go to the council covering your address, and the work needs building control approval. We prepare and submit the applications for you.
Do I need planning permission for a structural alteration in West Glamorgan?
In Wales removing a load-bearing wall needs building regulations approval with structural calculations, and party wall notices where a shared wall is involved.
What fire protection does a steel need?
Usually fire-rated plasterboard or intumescent paint, as building control requires.
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 building regulations approval?
Yes. Removing a load-bearing wall is building work that needs approval, with calculations for the beam.
