How to Clean and Maintain Rendered Walls

Daniel Nikolla

Oct 11

2 min read

Rendered walls need little care, but a yearly check and a gentle clean keep them looking good and protect them for longer.

An annual routine

Inspect. Walk around the house once a year and look for cracks, hollow-sounding areas, staining and gaps around windows.
Check the water. Make sure gutters, downpipes and overflow pipes aren't leaking onto the wall.
Clean. Wash with a soft brush or sponge and low-pressure water with a little mild detergent. Work from the top down and rinse well.
Fix small problems. Seal hairline cracks and gaps early, using products compatible with your system.

Brick wall meeting a clean white rendered wall with soffit and fascia, by Alb Render

What not to do

Don't pressure-wash at close range. High pressure can damage the surface and force water behind the render.
Don't use harsh abrasives or wire brushes.
Don't paint over pre-coloured silicone render with ordinary masonry paint, which can block its breathability.

Green and black marks

Algae and mould appear on shaded, damp walls, often north-facing ones, and under leaking gutters or beside overgrown plants.

Use a biocidal wash made for render, applied exactly as the label says, and protect plants and surrounding surfaces.
Let it work, then rinse gently.
Fix the cause: repair the gutter, cut back vegetation and improve airflow.

Silicone systems resist algae better than many other finishes, but no render is completely immune.

Check the ground level

Soil, patios or flower beds piled against the base of the wall can let moisture splash or wick into the render. Keep a clear gap above ground level.

How often?

A light wash every year or two is enough for most homes. Some through-coloured finishes benefit from a more thorough soft wash every four to five years.

When to call a professional

If you see wide or growing cracks, hollow areas when you tap the wall, damp patches inside, or crumbling at the base, get it assessed before water causes bigger problems. Alb Render can inspect and repair render, including patch repairs. Send photos on WhatsApp on 07846 928256.