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 South Glamorgan?
In South Glamorgan, a structural alteration typically costs £4,250–£8,750 for a typical knock-through with steel beam, including VAT at 20% (standard rate). That range is adjusted for Wales, where domestic building work typically costs around 8% below the national average. 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:
- Flush or downstand beam
- Moving radiators, sockets and pipes
- What sits above the wall
- Party wall involvement
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 South Glamorgan?
Whether you need planning permission depends on your house and its location 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.
At the survey we check your house’s planning history and any restrictions, and tell you which route applies.
What we handle
The work we manage on a structural alteration:
- Building control sign-off
- Structural engineer’s calculations and drawings
- Party wall notices where needed
- Fire protection to the steel
- 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 South Glamorgan
Terraced houses in Welsh towns often have narrow plots, which suits rear and side return extensions and rear dormers.
Towns we cover in South Glamorgan include Cardiff, Barry and Penarth.
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 fixed quote
Drawings, structural calculations and an itemised, fixed price for the agreed specification.
- 03
Permissions sorted
Applications, building control and neighbour arrangements, all before the start date.
- 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 South Glamorgan
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.
Do I need planning permission for a structural alteration in South 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.
How much does a structural alteration cost in South Glamorgan?
In South 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 South Glamorgan?
Planning matters in South Glamorgan 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.