Flat & HMO conversion steels · Cardiff
Flat & HMO conversion steels in Cardiff
Calculations, approvals, propping, steel and making good for flat & HMO conversion steels across Cardiff.
- Price fixed in writing once scope is agreed
- Building control arranged
- Temporary works and making good included
- Free survey visit
- Engineer's calculations arranged
- Building control handled
- Fixed written price once scope is agreed
- England, Wales, mainland Scotland & NI
About our flat & HMO conversion steels service in Cardiff
Flat and HMO conversion steels are the beams, columns and frames needed when a house or building is reworked into self-contained flats or a house in multiple occupation. New layouts move walls, stairs and bathrooms, so steel picks up the loads that old walls used to carry, designed to work alongside the fire separation and sound insulation the conversion also needs.
Looking for flat & HMO conversion steels in Cardiff? That covers every postcode district in the area. Our teams handle the calculations, the building control approval, the propping and the steel itself, and leave the opening ready for plastering and decoration.
What to expect
- Large Victorian and Edwardian houses are popular for conversion, but they bring timber lintels, chimney breasts, lime mortar and joists notched for old services. These are uncovered early so the engineer can account for them before any steel is ordered.
- Many HMOs need a licence from the local council, with conditions covering room sizes, shared facilities and fire safety. Licensing runs alongside building regulations rather than replacing them, so the layout and steelwork should suit both from the outset.
- The engineer looks at the whole building rather than one opening at a time. Loads from upper floors, new bathrooms and water storage are traced down to the foundations, and steel is placed so it suits the new layout without awkward downstands in habitable rooms.
- Steelwork is usually one of the first structural stages in a conversion. Getting beams in, inspected and fire protected early lets partitions, services and separating construction follow on, so any delay to the steel tends to hold up every trade after it.
- Keep the structural calculations, building control completion certificate and fire protection records together in one place. They are needed for signing off the conversion, and buyers, lenders and licensing officers may ask to see them later.
What happens, step by step
Free visit
A short visit to Cardiff to see the job, agree what you want and check the bearings, floors and services that affect the design.
Calculations
The engineer's calculations and a simple drawing are prepared for your opening and shared with you before anything is ordered.
Building control
We submit the application or notice to Cardiff Council under the Building Regulations as they apply in Wales, before work starts.
Steel in, made good
On site we prop, open up, fit and pack the steel, then fire protect, box in and plaster once the inspection is done.
How much should I budget in Cardiff?
As a guide, budget £2,300–£8,200 including VAT for steelwork for a flat or HMO conversion in Cardiff, based on published UK cost guides adjusted for prices in Wales (-9%).
| Job | Typical guide range | What it usually covers |
|---|---|---|
| Steelwork for a flat or HMO conversion | £2,300–£8,200 | Beams and posts for a revised layout, with approvals; fire and sound separation priced with the conversion |
| Fire protection to a steel beam | £140–£550 per beam | Fire-rated board boxing or an intumescent coating system as specified |
| Steel column or post | £460–£1,360 per column | Column supplied and fitted with base and cap plates on a pad foundation |
| Load-bearing wall removal with steel beam | £1,800–£4,550 | Typical internal wall up to about 4 m: calculations, building control, propping, steel, padstones, fitting, fire protection and making good |
Figures include our approximate regional adjustment for prices in Wales (-9%) and are rounded. How these figures are worked out.
Building control and neighbours in Cardiff
In Wales, structural alterations come under the Building Regulations 2010 as they apply in Wales. Cardiff Council handles building control for Cardiff. For work started or approved from 1 July 2026, the Welsh system uses an application to building control, dutyholders appointed in writing, a commencement notice before work starts and a compliance statement at the end.
The Party Wall etc. Act 1996 applies in Wales as well as England, so a beam bearing into a shared wall needs a party structure notice at least two months before work starts. We arrange notices through a party wall surveyor.
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Local questions answered
How much do flat & HMO conversion steels cost in Cardiff?
As a guide, budget £2,300–£8,200 including VAT for steelwork for a flat or HMO conversion in Cardiff, based on published UK cost guides adjusted for prices in Wales (-9%). The exact figure depends on the span, what the wall carries, access and the finish, and is fixed in writing once the scope is agreed.
Do I need a party wall agreement for flat & HMO conversion steels in Cardiff?
Yes, if the beam bears into a shared wall: the Party Wall etc. Act 1996 applies in England and Wales, and a party structure notice must be served at least two months before that work starts. We arrange it through a party wall surveyor.
Does 5% VAT apply to a flat conversion?
It may. A reduced rate of VAT can apply to some conversion work, such as changing the number of dwellings in a building or converting a house into an HMO, provided the conditions are met. The rules have detail and exceptions, so confirm the position with your accountant before pricing the project on that basis.
Can you install the steel while my main contractor runs the conversion?
Yes. On many conversions the steelwork is installed as a package within a wider build, working to the main contractor's programme and the engineer's design. We coordinate propping, deliveries and building control inspections for the steel so the other trades can follow on smoothly once it is in.
Do I need an HMO licence before converting a house?
Possibly. Many HMOs need a licence from the local council, and some areas license smaller HMOs too. Licensing covers room sizes, amenities and fire safety, and it is separate from planning and building regulations. Check the council's requirements early, as they can affect the layout and therefore the steelwork needed.
Does steel in a flat conversion need fire protection?
Yes, in almost all cases. Steel holding up floors that separate flats, or supporting escape routes, needs fire resistance to the period the scheme requires, which can be higher than in a single house. It is usually boxed with fire-rated board or coated with intumescent paint, and building control inspects it before handover.
Do you cover Cardiff for flat & HMO conversion steels?
Yes. We carry out flat & HMO conversion steels in Cardiff. Book a free survey visit and we will check the wall, arrange the engineer's calculations and send an itemised written quote.