Mould on Your Outside Walls? Let's Clean It Up and Keep It Away in Birmingham

Mould and algae on outside walls are common in the West Midlands climate, where shaded elevations stay damp for long stretches. The growth itself is unattractive and can hold moisture against the wall, but it is also a clue: it grows where the wall stays wet, so the pattern often points to a drainage, shading or ventilation issue worth fixing. Here is what causes it, how we clean it, and how to keep it from coming back.

Why walls grow mould and algae

Algae and mould spores are everywhere in the air; they colonise any surface that stays damp long enough. Shaded north and east walls that never dry fully are prime candidates. Leaking gutters and downpipes feed a constant trickle down one strip of wall. Soil, sand and dust deposits on damp surfaces give the organisms something to grow in. Rendered walls with porous or aging finishes hold surface moisture longer than dense brick. Walls splashed by sprinklers, shaded by dense vegetation, or sitting in still air behind fences and sheds also stay wet.

The colour tells you roughly what you have: green film is usually algae, black speckling often mould or cyanobacteria, orange or rust tones commonly lichen — slower growing and an indicator the surface has been damp for years.

How we clean it safely

We start by protecting the surroundings: plants, lawns and ponds near the wall are covered or rinsed, and anything electrical or delicate is noted. Growth is removed with appropriate cleaning methods for the surface — soft brushing and suitable cleaning solutions for most walls, gentle low-pressure rinsing rather than aggressive pressure washing, which drives water into joints and can lift render edges. Where a surface is fragile or the growth is heavy, we work in stages rather than trying to strip everything in one pass.

Delicate cases get extra care. Old lime render and very old brickwork can be damaged by harsh chemicals or high pressure, so cleaning is matched to the material. If the wall has sealed paint or render that is failing, cleaning may be combined with the repair work described elsewhere on our site.

Finding why it grows there

Cleaning without addressing the moisture is only half the job. We check gutters, downpipes and splash zones, look at what is shading the wall, and note where ground levels or surfaces feed water at the base. Vegetation pressed against the wall is trimmed back where agreed. We then give you plain advice on what will keep the surface drier — pruning, gutter maintenance, or repairs to a porous finish — so the clean lasts.

Limits and honest expectations

Cleaning improves appearance and removes the moisture-holding growth, but spores remain in the air and will recolonise a damp surface given time. We do not guarantee that growth will never return — its return depends on shading, weather and the drainage maintenance that follows. Some staining, especially old lichen, leaves a shadow even after the organism is dead, and we will say so in advance rather than promise a factory-fresh wall. Chemical cleaners are chosen and applied with care; we avoid anything that would harm plants, pets or the wall itself, and we agree green waste and runoff handling with you before starting.

Aftercare

Keep gutters clear and repair leaks promptly so water never runs down the wall. Prune vegetation back so air can move around the surface. Check the wall each spring — catching early regrowth makes it a five-minute job rather than a project.

Booking your clean

Book through maintenance-men.com or by phone. You pay a booking fee when you book, and labour is charged hourly at a rate that depends on how soon you need the visit. The full cost is quoted and approved before work starts, with any cleaning materials quoted separately. Tell us the wall's size, the extent of the growth and anything nearby we should protect.