Can an existing render finish be recoloured?

When recolouring works and when it does not

Recolouring suits render that is sound and compatible with the new coating. Tapping can help find hollow patches, but the existing paint, cracks, damp areas and adhesion also need checking. Weber’s guide starts with a suitable surface, then cleaning and preparation before the decorative finish goes on.

It is the wrong job when the render is failing. A coating is a film a fraction of a millimetre thick. It will not hold hollow render to the wall, and a moving crack will soon reappear through it. On a wall like that, painting only hides the evidence for a while.

Most walls sit in between. Local repairs to a cracked corner, a blown patch near the ground or a damaged area beside a downpipe are made first, left to cure, and then the whole elevation is coated so the patches disappear. A respray after repairs evens out the colour, but it will not flatten a rough patch on a smooth wall, so repairs need finishing to match the surrounding texture.

The render type matters as well. A painted sand-and-cement render is the usual candidate. A lime render needs limewash or a breathable mineral finish; the SPAB does not recommend standard modern paints on lime. Through-coloured silicone or monocouche can be coated, but only with a product its maker accepts on that surface.

Render repair ↗

Cleaning and preparing the surface

Preparation decides how long a new colour lasts. Algae, lichen and dirt are killed and washed off first, because a coating over live growth will discolour and lift. Structherm, for example, specifies its own algae cleaner before its silicone masonry paint and asks for a surface that is dry, cured and free of efflorescence, loose material and dust.

Washing needs care. A low-pressure rinse after a biocidal treatment cleans without driving water into cracks; a powerful jet held close can erode soft render and soak the wall, which then needs days to dry before coating. Flaking old paint is scraped back to a firm edge, and chalky surfaces may need a stabilising primer if the coating system calls for one.

Choosing the colour on the wall itself

Paint a trial square of the chosen coating on the render, on a face that gets ordinary daylight, and let it dry completely before judging it; Structherm recommends a sample to check colour and final appearance before its silicone masonry paint is used. The same colour looks different on a coarse dash, a scraped render and a smooth sand-and-cement face, so the trial belongs on the texture you actually have.

Decide what is not being painted. Stone sills, brick plinths, door surrounds and vents are small but obvious if they are coated by mistake, and plastic frames and meter boxes should be masked rather than cut in by eye. Note the product and colour reference once chosen, because a later patch or a new wall will need the same one.

A worked example from start to finish

For example, picture a hypothetical rendered semi with a faded cream front, green staining under the bay and two cracked corners beside the front windows. The tap test finds the render solid apart from a hand-sized drummy patch below one sill.

The sequence would be: treat the green growth with a biocidal cleaner and rinse at low pressure; cut out the hollow patch and the two cracks back to sound render, bed mesh across the corners and rebuild them to match the texture; then wait until the repairs and the wall are fully cured and dry, as the coating's data sheet requires. While waiting, the sill is checked, because if it barely projects past the render, the staining will return and the sill needs extending first.

Once dry, everything that is not being coated is masked, and two coats go on across the whole front from one batch. The side wall, which is in the same cream, is either included or left as a deliberate boundary at the corner; decide that before the first coat, not when the front looks newer than the side.

Applying the new colour

Masking takes a good part of the time. Frames, glass, sills, door furniture, brickwork, paving and anything else not being coated is covered, especially if the coating is sprayed, because the mist drifts. Small details such as vents, meter boxes and the underside of sills are easy to miss and obvious afterwards.

Most masonry coatings go on in two coats. Structherm's instructions for its silicone masonry paint, as one example, are a first coat thinned with up to 10% water, then an undiluted second coat once the first has dried, about 8–12 hours later, applied between 5°C and 30°C. The data sheet also asks for the same batch across a full elevation so the shade does not change partway along.

Weather matters for paint as much as for render. Rain on a fresh coat washes and streaks it, frost spoils it, and full sun on a hot day dries it too fast to lay off evenly. Exposed walls are usually coated on a dry, settled day, following the shade round the house.

Colour can also be a planning question in parts of the district. Wakefield Council lists Article 4 directions in the Heath, St Johns and Whitwood Terrace conservation areas, and the St John's appraisal refers to a direction on paint schemes there. If your house might be on one of the affected property schedules, check with the council before changing its colour.

The colour-change service page covers the coating route, while render repairs deals with local defects. Use both when repairs come before decoration, and keep the product and colour reference for the next time the wall needs attention.

Related services

Recolouring only works on sound render. The Wakefield rendering homepage explains how a wall's condition points to a repair, a new colour or a full re-render.