Wall Skimming in Islington | Full Re-Skim Case Study by London Plastering Service

This project took place in a Victorian terraced house in Lambeth, South London — a property type common across inner London boroughs including Islington. The rooms featured original high ceilings with period door architraves and skirtings still in place. The walls had been painted and decorated over many times across the decades, with a heavily textured, pitted surface typical of older properties that were never properly skimmed after the original lime plaster was painted over. The property appeared to be mid-refurbishment at the time of our visit, with furniture and fittings already cleared.

Both rooms photographed showed walls in poor decorative and structural condition. The first image shows a wall with a heavily textured, stippled surface — consistent with old sand and cement render or a roughcast painted finish — that had begun to delaminate in a vertical strip running approximately 600mm down from ceiling height. The plaster in this area had blown and was peeling away in sheets, exposing the substrate beneath. A ceiling light fitting had been removed, leaving a bare backplate, and protective dust sheets were taped across furniture and fittings using green tape. The second image shows a ceiling that had already been freshly skimmed — a smooth, wet multi-finish skim coat clearly visible — framed by white-painted coving, with the walls below still unfinished and marked with graffiti-style writing, suggesting the property had been vacant or was undergoing significant renovation.

The scope of work across this property covered wall re-skimming throughout multiple rooms of the Victorian terrace. Based on the images, the project involved the following elements: removing or stabilising areas of blown and delaminating plaster on the textured walls before any skim coat could be applied; preparing the existing wall surfaces by raking out loose material, brushing down, and applying a diluted PVA bonding solution to seal the porous substrate and improve adhesion; skimming all prepared wall surfaces with two coats of British Gypsum multi-finish plaster — a scratch coat worked into the substrate, followed by a trowelled finishing coat; and separately, skimming the ceiling in at least one room, which is shown in the second image in a freshly completed wet state. The ceiling skim appears to have been applied directly over an existing substrate, framed by original period coving that was masked and protected throughout. Protective dust sheets and green masking tape were used throughout to protect door frames, skirtings, and remaining furniture, as clearly visible in the first photograph.

Before any skim plaster was applied to the walls, the areas of blown and peeling plaster were carefully removed by hand and with a scraper to expose a sound substrate. The delaminated strip visible in the first image — where the textured coating had pulled away from the wall — was raked back to a clean edge to prevent future lifting at the repair boundary. All loose material was brushed away and the wall surface was treated with a PVA bonding coat diluted approximately 1:4 with water on the first pass, allowed to dry, then followed with a neat PVA tack coat applied immediately before plastering to ensure the multi-finish skim bonded correctly to the old, absorbent wall surface.

With the walls stabilised and primed, the plasterer applied British Gypsum multi-finish plaster across the wall surfaces in two stages. The first coat — the scratch coat — was applied at approximately 3–5mm thickness using a steel plastering trowel, worked firmly into the wall to ensure full contact with the PVA-primed substrate. This coat was cross-scratched lightly before it fully set to provide a key for the finishing coat. Once the scratch coat had firmed up sufficiently, the second coat of multi-finish was applied and laid off flat using broad trowel strokes, working from the top of the wall downward. As the plaster stiffened, it was trowelled up progressively — first with light water misting to keep the surface workable, then with dry trowel passes to close the surface and bring up a smooth, flat finish ready for decoration. The ceiling, visible in the second image in its freshly skimmed wet state, was treated in the same two-coat method. The fresh skim coat on the ceiling shows the characteristic dark, wet appearance of newly applied multi-finish before it has dried and turned the familiar off-white colour. The coving surrounding the ceiling was carefully cut in by hand to maintain a clean line between the new plaster and the existing painted coving profile.

The main technical challenge on this project was the condition of the existing textured wall surface. The stippled, rough-coat finish had been painted over multiple times and had begun to delaminate — as clearly visible in the first image where a vertical section had blown and was peeling away in a sheet. This type of failure typically occurs when moisture gets behind the finish coat or when the bond between successive paint and plaster layers breaks down over time. Attempting to skim directly over a surface in this condition without proper preparation would have resulted in the new skim coat pulling away from the wall as the unstable substrate beneath continued to fail.

The failed section of textured wall was removed back to sound material before any new plaster was applied. Rather than attempting to feather in a patch repair — which would have left a visible edge line through the finished decoration — the plasterer took the repair back to natural break points and re-skimmed the entire wall face in one continuous coat. This approach ensured a flat, consistent surface with no step or ridge where old and new plaster met. The porous wall substrate was double-coated with PVA to reduce suction and give the multi-finish skim coat the working time needed to be laid off flat before it stiffened prematurely.

The ceiling in the second image shows the freshly completed skim coat in its wet state — a smooth, even surface with no visible trowel lines or ridges, framed cleanly against the existing period coving. Once dry, this surface would be ready for mist coat and decoration. The wall surfaces across the property were re-skimmed flat, removing the years of built-up textured finish and delaminated plaster that had made the rooms difficult to decorate. The finished walls provided a flat, consistent surface suitable for painting without the need for extensive filling or sanding by the decorator.

The client — who was mid-way through refurbishing this Victorian terrace — was able to move forward with decoration across the property following completion of the plastering. The re-skimmed walls and freshly plastered ceiling removed the need for the decorator to apply multiple layers of filler to level the old textured surfaces, saving time and cost at the decoration stage. The rooms were left clean, with all dust sheets and masking tape removed on completion, ready for the mist coat to be applied once the plaster had cured fully — typically 4–6 weeks for multi-finish plaster of this thickness.

Skimming over blown or delaminating plaster without removing the failed material first is one of the most common causes of plaster failure shortly after redecoration. A new skim coat applied over an unstable substrate will move and crack as the layers beneath continue to detach from the wall. On this Lambeth project, identifying and removing the blown section before plastering — rather than simply skimming over it — is what ensures the new finish will last. Applying PVA correctly, at the right dilution and at the right time before plastering, is equally critical: too dry and the skim pulls off, too wet and it slips.