Steel BeamInstallers
Plasterer seen from behind skimming a newly boxed beam

Plastering & making good · Cardiff

Plastering & making good in Cardiff

Survey, engineer's design and installation of plastering & making good anywhere in Cardiff.

  • Survey, design and installation in one
  • Covering CF10, CF11, CF14, CF15
  • Inspected before it is covered

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

Plastering & making good in Cardiff: how it works

Plastering and making good is the finishing work after a beam goes in or a wall comes out: boxing the steel, fixing corner beads, patching ceilings and wall ends, infilling the floor where the wall stood and skimming everything smooth. The aim is a room that looks as if the opening was always there, ready for paint.

Plastering & making good is one of the most common structural jobs in homes across Cardiff. That covers every postcode district in the area. Every job starts with a survey visit, then calculations from a structural engineer, so the steel suits the house in front of us rather than a rule of thumb.

Key points for your project

  • Fresh plaster has to dry before it is painted. A thin skim over board in a warm, ventilated room often dries within a few days to a week, while backing coats and deeper repairs take longer. Painting too soon can cause peeling and patchy colour.
  • New plaster is very absorbent, so the first coat of emulsion is normally thinned with water as a mist coat to seal it. Skipping this step is a frequent reason paint flakes off fresh plaster within weeks of decorating.
  • The cost depends mainly on the area to repair, the condition of the ceilings, whether period details need matching, and the size of the floor infill. Overboarding a badly damaged ceiling can work out more economical than patching it piece by piece.
  • Victorian and Edwardian ceilings are often lath and lime plaster, which can sag or come away when nearby work shakes it. Small areas can be patched to match, while larger damaged areas are usually overboarded or replaced for a sound result.
  • Metal angle beads on every outside corner of the boxing give crisp, straight lines and protect the edges from knocks. They are set true to the ceiling and walls, so a slightly out-of-level beam does not show once skimmed.

From survey to sign-off in Cardiff

  1. 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.

  2. Calculations

    The engineer's calculations and a simple drawing are prepared for your opening and shared with you before anything is ordered.

  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. 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.

Guide prices for plastering & making good in Cardiff

As a guide, budget £270–£1,090 including VAT for plastering and making good in Cardiff, based on published UK cost guides adjusted for prices in Wales (-9%).

JobTypical guide rangeWhat it usually covers
Plastering and making good£270–£1,090Boxing the beam, bead and skim, reveals, floor infill where the wall stood and tidy-up
Through-lounge knock-through£2,300–£5,000Wall between front and back reception rooms, steel beam, approvals, plastering and floor infill
Fire protection to a steel beam£140–£550 per beamFire-rated board boxing or an intumescent coating system as specified
Kitchen-diner knock-through£2,300–£5,450Internal structural wall between kitchen and dining room, steel beam, approvals and making good (kitchen fitting extra)

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.

Building rules in Wales

Local questions answered

How much does plastering & making good cost in Cardiff?

As a guide, budget £270–£1,090 including VAT for plastering and making good 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.

Can I stay at home while the work is done in Cardiff?

Usually, yes. The work area is screened and floors are protected. The rooms either side of the opening are out of action for a few days, and there is some noise and dust while the masonry comes out.

Can you repair a lath and plaster ceiling?

Yes. Small areas can be patched with lath and lime-based plaster, or with board cut in and skimmed to match. Where large areas have sagged or pulled away from the laths, overboarding or replacing the ceiling is often the sounder repair. We assess the condition at the survey and price the right approach.

Can you match my old textured ceiling?

Often, yes, although a perfect match is hard over large patches. Before anything is touched, a textured coating applied before 2000 is tested for asbestos. Small areas can then be re-textured to blend in, while many people choose to skim the whole ceiling flat for a cleaner, consistent finish.

How do you hide a steel beam in the ceiling?

Most beams are boxed with fire-rated plasterboard fixed to a light frame, then finished with corner beads and a skim coat so they read as part of the ceiling. If you want no downstand at all, the beam has to be set into the floor void when it is installed, which is decided at the design stage.

Will cracks appear after plastering?

Small hairline cracks can appear in the first months as the plaster dries and the building settles onto the new steel. They are cosmetic and normal, and are usually filled when you next repaint. Wide or growing cracks are different and should be reported, as they can point to movement that needs checking.

Can you work on older or listed homes in Cardiff?

Yes. Older homes often have lime mortar, timber lintels or shallow footings, which the engineer allows for. Listed buildings need listed building consent for internal structural changes as well as building regulations approval, and that must be in place first.

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.