Cladding does not fail loudly. It collects pollution, algae and traffic film slowly enough that nobody notices, and then one day a tenant, a buyer or a board member looks up and the building reads as tired — long before anything is actually wrong with it.
By that point the conversation has already changed. It is no longer about maintenance; it is about why the building looks neglected.
This guide covers what commercial cladding and facade cleaning actually involves, how the two main methods differ and why choosing the wrong one damages the surface, how often different building types need it, and the additional rules that apply to listed and historic buildings.
Cladding cleaning and facade cleaning are the same job
Worth clearing up, because the two terms are used interchangeably in quotations and it causes confusion at tender stage.
Both describe cleaning the external surfaces of a building: metal and composite cladding panels, painted and unpainted render, brick, stone, concrete, uPVC, timber, fibre cement and curtain walling frames. Facade tends to be used for the whole elevation, cladding for the panel system specifically. A quotation should list the materials and elevations rather than rely on either word.
What matters far more than the label is the material, because the material decides the method.
Soft washing or pressure washing: the choice that damages buildings
This is where most avoidable damage happens.
Soft washing uses low-pressure application with specialist cleaning solutions that break down algae, moss, lichen and organic growth chemically rather than by force. It suits almost everything: painted and powder-coated finishes, render, composite, uPVC, timber, older or fragile cladding, and anything with a surface coating that pressure would strip.
Pressure washing uses high-pressure water to shift stubborn grime, oil and staining. It is appropriate for robust surfaces — concrete, some metals, hardstanding, loading bays — where the finish can take it.
The failure mode is using pressure where soft washing was needed. On powder-coated cladding it chips and dulls the finish. On render it drives water into the substrate and can strip the coating entirely. On older timber it raises the grain. None of it is reversible, and the repair costs more than the clean did.
A contractor who asks what the cladding is made of before quoting is telling you something useful. One who quotes "pressure washing" for an entire building without asking has not looked at it.
What biocide treatment actually does
Worth understanding, because it changes the economics of the whole programme.
Cleaning removes the visible growth. It does not remove the spores, so on a north-facing or sheltered elevation algae typically returns within six to twelve months — which is why a building that was cleaned last year can look untreated again.
A biocide treatment applied after cleaning inhibits regrowth, and reputable suppliers quote protection in the region of four to five years rather than months. It reactivates with rainfall rather than washing straight off.
The practical consequence for a maintenance budget: a clean with biocide on a long cycle usually costs less over five years than repeated cleaning without it. When comparing quotations, check whether biocide is included or whether the cheaper price is for cleaning alone.
How often does commercial cladding need cleaning?
There is no single answer, and any contractor who gives one without seeing the building is guessing. The published guidance across the industry clusters around these ranges:
- Office buildings — every 12 to 18 months, usually driven by presentation rather than condition
- Industrial units and logistics — every 12 to 24 months, more often where there is vehicle traffic, emissions or process residue
- Retail — quarterly to twice yearly on high-visibility frontages, annually elsewhere
- Coastal buildings — every 6 months within about a mile of the coast; salt spray corrodes metal cladding and stains composite finishes
- Healthcare and education — driven by presentation standards rather than soiling rate
Four things shorten the cycle regardless of building type:
Orientation. North-facing and shaded elevations stay damp and grow algae several times faster than south-facing ones. Most buildings do not need every elevation cleaned at the same frequency, and a programme that treats them identically is over-serving one and under-serving another.
Traffic and pollution. Buildings on busy roads, in industrial estates, beside car parks or loading bays accumulate traffic film that dry cladding elsewhere never sees.
Trees. Overhanging vegetation means shade, moisture, leaf debris and bird activity in one package.
Birds. Droppings are acidic and stain locally. Where there is a roosting problem, cleaning alone is a recurring cost until the roosting is dealt with.
Why elevations stain in the first place
A large share of facade staining is not airborne dirt — it is water going where it should not.
A blocked gutter spills over the edge and runs straight down the elevation, leaving the vertical dark streaking that is instantly recognisable once you know what causes it. Cleaning it off without clearing the gutter means it returns the following winter. This is why we usually recommend surveying commercial gutter cleaning and facade condition together rather than separately.
The same applies to failed hoppers, displaced downpipes, blocked outlets on flat roofs, and overflow pipes discharging onto a wall. If the same stain comes back in the same place, the cause is above it.
Listed and historic buildings: different rules
Hertfordshire, St Albans and much of north London have significant listed building stock, and the rules are genuinely different.
Cleaning a listed building can require listed building consent. Consent is needed for works affecting a building's character or special architectural or historic interest — and depending on the method and the surface, cleaning can fall within that. Abrasive methods, chemical treatments and anything that would alter the appearance of historic fabric are the areas of concern.
The practical position: speak to the local authority's conservation officer before any work is specified. They will say whether consent is required for the method proposed. Carrying out unauthorised works to a listed building is a criminal offence, so this is not a step to take on assumption.
Beyond consent, historic surfaces need gentler treatment as a matter of course. Soft lime-based renders, historic brick and weathered stone can be damaged by methods that modern cladding tolerates easily, and the damage is permanent.
A contractor who raises the consent question before you do is one worth talking to.
Access decides the price
Facade cleaning is priced by how you reach the surface, not by its area.
Ground-based systems with telescopic poles reach a useful height and keep the operative on the ground, which removes the fall risk rather than managing it. Above that, powered access, towers or rope access are used depending on height, ground conditions and what sits beneath the work.
We cover this in detail in our guides to access methods for buildings of any height and what to check before hiring a contractor for work at height.
The useful consequence for a budget: once access is mobilised, cleaning the rest of the elevation is marginal cost. If a MEWP or rope team is on site for the glazing, adding the cladding, the frames and the signage on the same visit is dramatically cheaper than a separate mobilisation later. Buildings that clean glass frequently and facade never are usually paying for access twice.
Frequently asked questions
How often should commercial cladding be cleaned? Office buildings typically every 12 to 18 months, industrial units every 12 to 24 months, and high-visibility retail frontages quarterly to twice yearly. Coastal buildings within about a mile of the sea often need cleaning every 6 months. North-facing and shaded elevations soil faster than south-facing ones and may need a shorter cycle than the rest of the same building.
Is soft washing or pressure washing better for cladding? Soft washing for most cladding — painted and powder-coated panels, render, composite, uPVC, timber and any coated finish. Pressure washing only on robust surfaces such as concrete and some metals. Using pressure where soft washing was needed chips coatings, strips render and causes damage that costs more to repair than the clean.
What does biocide treatment do after cladding cleaning? Cleaning removes visible growth but not the spores, so algae typically returns within six to twelve months on north-facing elevations. A biocide treatment applied afterwards inhibits regrowth for around four to five years, reactivating with rainfall. Over a five-year budget it usually costs less than repeated cleaning without it.
Do you need consent to clean a listed building? Possibly. Listed building consent is required for works affecting a building's character or special interest, and depending on the method and surface, cleaning can fall within that. Speak to the local authority's conservation officer before the work is specified — unauthorised works to a listed building are a criminal offence.
Why does the same stain keep coming back on our building? Recurring stains in the same position are almost always water rather than airborne dirt — a blocked gutter, a failed hopper, a displaced downpipe or an overflow discharging onto the wall. Cleaning the stain without fixing what is above it means it returns the following winter.
Cladding and facade cleaning across London, Hertfordshire, Essex and Kent
FG Cleaning has cleaned commercial building exteriors since 2003, from a base in Enfield. We survey the building first, identify the materials and the cause of any staining, and specify the method per elevation rather than applying one method to everything.
Every survey comes with a written report: condition by elevation with photographs, anything found that needs repair rather than cleaning, the access method proposed, and a recommended frequency with the reason for it.
Our related services include exterior and cladding cleaning, window cleaning and gutter and fascia clearance, across Hertfordshire and the surrounding counties.
If your building has staining you are unsure about, or you are planning a maintenance programme, the survey is free and you keep the report either way.
Or call 0800 612 9349.