Steel BeamInstallers
Steel beam half boxed in pink fire-rated plasterboard

Fire protection for steel beams · Cardiff

Fire protection for steel beams in Cardiff

Survey, engineer's design and installation of fire protection for steel beams anywhere in Cardiff.

  • Price fixed in writing once scope is agreed
  • Building control arranged
  • Temporary works and making good included

Free survey in Cardiff

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  • Free survey visit
  • Engineer's calculations arranged
  • Building control handled
  • Fixed written price once scope is agreed
  • England, Wales, mainland Scotland & NI

Planning fire protection for steel beams in Cardiff

Fire protection for steel beams is the layer of fire-rated board or intumescent coating applied to structural steel so it keeps its strength long enough in a fire for people to get out. Steel softens as it heats, so building regulations set a period of fire resistance for beams and columns, and the protection is chosen and applied to meet that period.

Looking for fire protection for steel beams in Cardiff? We cover the whole area, from the centre out to the suburbs. Our teams handle the calculations, the building control approval, the propping and the steel itself, and leave the opening ready for plastering and decoration.

Worth knowing before you start

  • Boarding is fairly clean work, but coatings need a clean, dry and well-ventilated room at a suitable temperature. Dust from other trades can spoil the surface, so painting is normally scheduled once the messy work in that room is finished.
  • A common fault is applying intumescent paint over the wrong primer, or over one of unknown type. The products must be compatible, so where steel was primed long ago the primer is identified or the surface is cleaned back before coating.
  • Intumescent paint looks like an ordinary coating but swells into a thick insulating char when heated. How well it performs depends on the dry film thickness, which varies with the steel section and fire period, so it is applied to a written specification.
  • Boxing is generally the lower-cost route for steel that will be hidden. Intumescent coatings cost more because of the product and the number of coats, and the price rises with the fire period and the size of the section.
  • Exposed steel is popular in open-plan kitchens and loft spaces. An intumescent system can take a decorative top coat in most colours, although up close the finish has a slightly textured look compared with steel painted in a factory.

How the job runs in Cardiff

  1. Survey in Cardiff

    We visit, look at the wall and what sits above it, measure the opening and note services, access and how the steel can be brought in.

  2. Engineer's design

    A structural engineer sizes the beam, padstones and any posts, and sets out the temporary support needed while the wall is out.

  3. Building control

    We submit the application or notice to Cardiff Council under the Building Regulations as they apply in Wales, before work starts.

  4. Install and sign-off

    Props go in, the opening is formed, the steel is set and packed, building control inspects it, and we make good.

How much should I budget in Cardiff?

As a guide, budget £140–£550 per beam including VAT for fire protection to a steel beam in Cardiff, based on published UK cost guides adjusted for prices in Wales (-9%).

JobTypical guide rangeWhat it usually covers
Fire protection to a steel beam£140–£550 per beamFire-rated board boxing or an intumescent coating system as specified
Plastering and making good£270–£1,090Boxing the beam, bead and skim, reveals, floor infill where the wall stood and tidy-up
Building control fees£230–£590Application fee and inspections under the Welsh building regulations; varies by council or approver
Steel beam replacement£1,800–£5,000Propping, removing the failed beam, new steel on proper bearings, approval and making good

Figures include our approximate regional adjustment for prices in Wales (-9%) and are rounded. How these figures are worked out.

Building rules for Cardiff

Welsh building regulations treat beams and new openings as controlled building work. We apply to Cardiff Council on your behalf before anything is removed, give the commencement notice the 2026 Welsh rules require, and the steel is checked before it is boxed in.

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.

Building rules in Wales

Fire protection for steel beams in Cardiff: your questions

What happens at the survey visit in Cardiff?

We look at the wall, the floor and ceiling either side and what sits above, measure the opening you want, and note cables, pipes and access for the steel. It usually takes under an hour and there is no charge.

Do I need a party wall agreement for fire protection for steel beams 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.

How long does intumescent paint take to apply?

Several days in most cases. Each coat has to dry before the next is applied, and the number of coats depends on the thickness needed. Cold or damp rooms slow drying, so the space is kept warm and ventilated, and the top coat goes on once the full build has been measured.

Can I box in a steel beam with normal plasterboard?

Not where fire protection is required. Standard plasterboard is not designed to protect steel for a set period in a fire. Fire-rated plasterboard is used instead, fixed in the number of layers and with the fixings the system specifies, so the boxing performs as intended and passes when building control checks it.

Is boxing in a steel beam cheaper than intumescent paint?

Usually, yes. Boxing with fire-rated plasterboard tends to cost less for steel that will be hidden. Intumescent coatings generally cost more because of the product and the number of coats needed, but they let the beam stay visible. Where either method would work, both can be priced on the itemised quote so you can compare.

What is intumescent paint for steel beams?

Intumescent paint is a fire-protective coating that swells when heated, forming a thick insulating layer that slows the steel heating up. It lets you leave a beam on show while still meeting fire requirements. It must be applied at a specified thickness over a compatible primer, so it goes on to a written specification rather than like ordinary paint.

How much does fire protection for steel beams cost in Cardiff?

As a guide, budget £140–£550 per beam including VAT for fire protection to a steel beam 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.

Planning to take a wall out?

Book a free survey visit. You get an itemised written quote covering calculations, building control, steel and making good.