Ceiling Replacement & Plasterboard Re-Skim by a Plasterer in Lambeth, SW8

This project was carried out at a Victorian terraced house in Lambeth, SW8. The ground-floor reception room is a generously proportioned space with period cornicing still intact along the wall-ceiling junction, double-aspect windows overlooking a rear garden, and original panel doors — all indicators of a late-Victorian build. The room had been recently refurbished with new LVT flooring and freshly painted walls, making the ceiling the final element requiring attention before the property was fully restored.

The existing ceiling had deteriorated beyond the point where a skim coat could rescue it. When inspected, the old plaster ceiling had failed structurally — it was stripped back entirely, exposing the bare timber joists above. Visible in the before photograph are the raw ceiling joists running across the full span of the room, with mineral wool insulation batts laid between them and multiple electrical cables and a copper pipe routed through the void. Several conduits and wire runs had been newly installed, indicating the property had recently undergone a full rewire and plumbing alteration. The old ceiling material had been completely removed, leaving no substrate in place for a direct skim.

The scope of work covered the complete reinstatement of the ground-floor reception room ceiling from bare joists through to a fully skimmed and paint-ready surface. This involved supplying and fixing new 12.5mm tapered-edge plasterboard sheets directly to the exposed timber joists across the full ceiling area. All board joints were taped using fibreglass mesh jointing tape — visible in the third image as the orange grid pattern running along every board edge and cross joint — and filled with a jointing compound to bring the surface flush before skimming. The light fitting drop was retained and routed through the new board. Once the boarding and jointing stage was complete, the entire ceiling received a two-coat application of British Gypsum multi-finish plaster, applied by hand trowel to achieve a flat, paint-ready surface. The cornicing at the perimeter was carefully protected throughout, and the finished ceiling — shown in the first image — sits flush against the retained period cornice with clean arrises at every edge.

Before any boarding began, the room was fully protected with heavy-duty polythene sheeting laid over the new LVT flooring and fixed up the walls to prevent dust and debris contamination. The existing electrical cables and copper pipe running through the joist void were checked and confirmed safe and correctly positioned by the client's electrician and plumber prior to our team attending. Each joist was checked for level using a straight edge, and any twist or bow was noted so that packing could be applied where needed to ensure the new boards would sit on a consistent plane. The perimeter cornicing was masked to protect it during the boarding and skimming stages.

New 12.5mm tapered-edge plasterboard sheets were cut to length and fixed directly to the ceiling joists using drywall screws at 150mm centres along each joist, with screws positioned no closer than 13mm from the board edge to prevent paper tearing. Boards were staggered in a brick-bond pattern to avoid continuous cross joints running the full width of the ceiling. Once all boards were fixed and checked for flat, all tapered joints and butt joints were filled using a two-stage process: a base coat of jointing compound was applied and embedded with fibreglass mesh tape, then a finish coat of jointing compound was feathered out wide on either side of each joint to eliminate any ridge. The screw heads were spot-filled at the same stage. After allowing the jointing compound to dry fully, the entire ceiling was mist-coated with a diluted PVA solution to even out suction across the boarded surface. Two coats of British Gypsum multi-finish were then applied by hand — a scratch coat worked firmly into the board surface, followed by a trowelled finishing coat laid tight and polished back as the plaster approached its initial set. The result, visible in the after photograph, is a uniformly flat ceiling with no visible joint lines.

The primary challenge on this project was the presence of live electrical cable runs and a copper pipe routed through the joist void at varying heights. Some of the cables dropped below the bottom face of the joists, which meant that simply fixing boards flat to the joist underside would have pinched or kinked the cables. Additionally, the joists themselves showed minor variation in level across the span of the room — common in Victorian properties where timber has moved over more than a century — which needed to be addressed before boarding to avoid the finished ceiling reflecting any dips or humps.

Before boarding, each electrical cable drop that fell below the joist face was carefully re-routed and clipped tight to the joist sides by the client's electrician, clearing the way for boards to be fixed flat. Where joists showed a bow or low spot, thin timber packers were fixed to the underside of the relevant joists to bring them into a consistent plane. A long straight edge was used across multiple joists at once to verify level before any board was lifted into position. These steps added time to the preparation stage but ensured the finished plasterboard ceiling was flat across its full span with no humps or hollows telegraphing through to the skim coat.

The completed ceiling is shown in the first image — a smooth, uniformly flat surface with no visible joint lines, screw marks or undulation. The new plaster sits cleanly against the retained Victorian cornicing at the room perimeter, with a crisp arris where the ceiling meets the cornice bed. The light pendant drop exits neatly through the centre of the ceiling. Photographed under natural light from the garden-facing windows, the ceiling shows no shadowing or ridging, confirming the board joints were correctly filled and the skim coat was applied at a consistent thickness across the full area.

The client had already invested in new flooring, freshly painted walls and updated skirting throughout the reception room. The ceiling was the last remaining element to bring the space up to the same standard. With the new plasterboard ceiling skimmed flat and ready for paint, the room is now complete and consistent throughout. The retained period cornicing ties the new ceiling back into the original character of the Victorian property, and the client was able to proceed directly to decoration without any further remedial work.

Replacing a ceiling from bare joists involves more than simply screwing up boards and skimming over them. Joist level variation, cable and pipe routing, board staggering, correct joint tape selection and compound application technique all affect whether the finished surface is genuinely flat or shows ridges, hollows and joint lines once painted. Applying multi-finish over an unprimed or unevenly jointed board surface causes the plaster to dry at different rates, leading to cracking or crazing. Getting each preparatory stage right before the skim coat is applied is what determines whether the finished ceiling remains flat and crack-free over time.