Most London commercial buildings should have their external windows cleaned monthly, with city-centre and high-visibility frontages moving to fortnightly. Interior glazing should be cleaned in line with the interior contract, usually monthly to quarterly. Here's the full breakdown by building type — and why London-specific factors push frequency higher than the UK average.
Recommended frequency by building type
| Building | External | Internal |
|---|---|---|
| City / West End office | Fortnightly | Monthly |
| Suburban Zone 2–4 office | Monthly | Quarterly |
| Retail frontage / showroom | Weekly | Weekly |
| Hotel | Fortnightly | Monthly |
| Restaurant / hospitality | Weekly | Weekly |
| Residential block (mansion, portered) | Monthly | Quarterly |
| Warehouse / industrial (M25 belt) | Quarterly | 6-monthly |
| School / academy | Half-termly | Termly |
Why London needs higher frequency than most UK cities
- PM2.5 and PM10 particulates from traffic settle on glass within days — city-centre offices show a visible film in 7–10 days.
- Higher pigeon and gull activity leaves droppings that etch into glass if not removed within 2–3 weeks.
- Dense pedestrian traffic means fingerprints and smudges on entrance glazing every day.
- Air-conditioning discharge from adjacent buildings drips over shared elevations.
- Ongoing construction across Zones 1–3 means silica dust hangs in the air year-round.
Check your lease before signing a contract
Most London commercial leases include a service-charge schedule that mandates a minimum frequency for external window cleaning, especially in prime-rent buildings. Signing a cleaning contract below the lease minimum risks a service-charge dispute at year-end. Ask your managing agent or landlord for a copy of the current schedule before agreeing frequency.