Kitchen Extension Ceiling Plasterboarding & Skim by a Plasterer in Lambeth

This project took place in a Victorian terraced house in Lambeth, SW8, where the homeowner had recently completed a rear kitchen extension. The extension featured a vaulted, pitched ceiling with two newly installed Velux rooflights and a set of French doors opening onto a rear garden. The kitchen itself retained its existing granite-topped units and cream cabinetry, but the newly built ceiling structure above required full plasterboarding and skimming before the renovation could be completed and decorated.

When our plasterer arrived on site, the vaulted kitchen extension ceiling was fully exposed — the timber framework and metal angle beads were visible, with pink insulation board already fitted between the rafters. The plasterboard had been partially fixed to the sloping ceiling sections, with tape applied along the board joints and in the angles between ceiling planes. The Velux rooflight frames had been installed but the surrounding reveals and ceiling sections were bare and unfinished. The walls at the junction between the original house and the new extension showed exposed blockwork where the old render had been removed, and the floor was unprotected screed — all consistent with a mid-renovation kitchen extension.

The scope of work covered the full plastering of the vaulted kitchen extension ceiling, including all sloped ceiling planes, the flat sections between the Velux rooflights, and the internal angles where the ceiling met the walls. The plasterboard had been fixed to the timber roof structure prior to our arrival, so the work began with taping and jointing the board seams and applying scrim tape to all internal angles. Both Velux rooflight reveals required skimming to match the surrounding ceiling. The upper wall sections at the junction between the original rear wall and the new extension structure also required a bonding coat and skim to bring them level and flush with the existing plaster. Protective dust sheets were laid across the kitchen worktops and appliances — including the washing machine and dishwasher — before any work commenced. The total ceiling area across the vaulted planes was substantial given the pitched nature of the roof, requiring careful staging and working at height throughout.

Before skimming could begin, all plasterboard joints were reinforced with paper jointing tape embedded in a thin layer of bonding compound and allowed to fully set. Scrim tape was applied to every internal angle — including the junctions between the sloping ceiling planes and the vertical walls. The exposed blockwork section on the rear wall was dampened down and treated with a diluted PVA bonding agent to reduce suction before the bonding coat was applied. The Velux rooflight frames were masked off to protect the factory finish. Dust sheets were draped over all kitchen units, worktops and appliances, and the French doors were left open to aid ventilation and drying during the skim process.

Once the preparation was complete and the bonding coat on the blockwork section had firmed up, skimming began on the vaulted ceiling. Given the pitch of the roof, the plasterer worked methodically across each sloped plane — applying the first coat of multi-finish plaster at a consistent thickness of approximately 2mm, working from the ridge line down toward the wall plate on each side. The natural light from the two Velux rooflights was used to read the surface and identify any low spots or ridges as the skim was applied. After the first coat had stiffened, a second tightening coat was applied and ruled off flat before being polished back with a damp sponge float. The internal angles between the ceiling planes were formed using a metal angle tool to achieve straight, defined arrises. The Velux reveals were skimmed individually, blending into the surrounding ceiling surface. The upper blockwork wall section received a scratch coat of bonding plaster, allowed to cure, followed by a full skim coat of multi-finish brought flush with the existing painted plaster below. The finished skim was left to dry naturally with good airflow from the garden-facing French doors.

The primary challenge on this project was working across a vaulted, multi-plane ceiling in a live kitchen environment. The pitched surface meant there was no flat reference plane to work from, and each ceiling section met at a different angle — making it difficult to achieve consistent thickness and flat arrises throughout. Working at height on a sloped ceiling also increases physical fatigue quickly, requiring the plasterer to take a staged approach rather than attempting to skim the entire ceiling in one continuous pass. Additionally, the two Velux rooflight openings broke up the ceiling surface into distinct sections, each of which needed to be skimmed independently and then blended together at the reveals.

To manage the vaulted ceiling effectively, the plasterer divided the ceiling into clearly defined working sections — tackling one sloped plane at a time and allowing each section to reach the correct stiffness before moving on. A straightedge was used to check flatness across each plane, and the internal angle tool was used consistently to keep the arrises between ceiling sections crisp and aligned. For the Velux reveals, each face was skimmed separately with the plaster feathered back carefully at the frame edge. Using the natural daylight flooding in through the rooflights as a raking light source helped identify any imperfections before the final tightening coat was applied.

The second image shows the completed skim across the full vaulted ceiling — a consistent, smooth multi-finish surface covering both sloped ceiling planes, the sections around both Velux rooflights and the upper wall section at the rear. The fresh plaster is an even mid-brown tone throughout, indicating uniform thickness and consistent drying. The arrises between the ceiling planes and around the Velux frames are sharp and well-defined. The kitchen extension ceiling is now fully ready for mist coat and decoration, bringing the renovation one step closer to completion.

The homeowner was mid-way through a full kitchen renovation when we completed the ceiling work. With the plasterboarding already fixed by their builder, our role was to take the raw shell and produce a surface ready for the decorator. Completing the vaulted ceiling skim in two days meant the renovation could continue on schedule without a delay to the decoration and fitting phase. The client confirmed the ceiling was exactly what was needed to move the project forward and that the Velux reveals in particular came out cleaner than they had expected given the complexity of the angles involved.

Skimming a vaulted, multi-plane ceiling requires a different approach to a standard flat ceiling — you cannot rely on gravity to help work the plaster evenly, and every change of angle creates an opportunity for an ugly, uneven arris if not managed carefully. Attempting this type of work without experience of working at height on irregular surfaces typically results in visible ridges, uneven thickness and poorly formed angles that will telegraph through paint. A plasterer familiar with extension ceiling work understands how to read a sloped surface using raking light, how to stage the work across multiple planes and how to blend reveals around rooflight frames cleanly.