Quick answer: Never balance a ladder on stairs to clean a stairwell window — angled steps plus a side-reach is the highest-risk cleaning setup in the house. The safe options, in order: a telescopic pole with a squeegee head worked from the landing or half-landing, a suction robot placed from the nearest reachable point of the pane, or a combination/platform ladder actually designed for stairs used exactly per its manual. The stairwell window is usually the biggest single light source on the staircase — it earns a proper clean twice a year.
Every multi-storey home has one: the tall window over the stairs that lights two floors, collects cobwebs at the top, and has no floor underneath it that a ladder can honestly stand on. It's the pane most likely to be dirty in an otherwise clean house — because there's no obviously safe way to reach it.
Why the stairs-plus-ladder combination is uniquely bad
A ladder needs level ground and a straight-on approach; a stairwell offers neither. The improvised solutions — one leg on a lower step, a plank across the stairs, leaning sideways from a step ladder on the half-landing — combine an unstable base, an off-axis reach and a hard-edged landing zone. Ladder falls are already the leading cause of serious DIY injury in the UK, and stairwells are where the worst of them happen. Whatever you do, don't improvise the base.
Method 1: telescopic pole from the landing (most homes)
A squeegee-and-washer head on a telescopic pole covers most stairwell windows from the landing, half-landing or hallway floor. Technique matters more than reach: wash top-down, squeegee in overlapping strokes, and re-wet stubborn top corners rather than stretching. Works best on the inside face; for the outside, see what's below the window outdoors — often it's reachable from ground level with the same pole.
Method 2: the suction robot (tall and awkward panes)
Stairwell windows are frequently the tallest single panes in the house — which makes them robot territory. Place the CleanBot R1 on the lowest reachable corner of the glass, anchor the safety rope to the banister or a landing fixture, and it maps and cleans the full height — including the top metre that no pole quite finishes properly. It works on the inside face year-round and the outside face wherever you can reach any part of the pane to place it. For panes divided by transoms, treat each section as its own pane — the pane-size rule explained.
Method 3: a stair-rated platform ladder (when you must)
If hands-on access is genuinely needed — say, first-time removal of years of grime — use a combination ladder or platform system actually rated for stairs, set up exactly per its manual, with a second person present. Rented for a day, it costs less than any A&E visit. What it's for is the one-off restoration clean; the maintenance cleans afterwards should never need it again — that's what methods 1 and 2 are for.
Worth the effort: it's your staircase's lightbulb
A grimy stairwell window dims two floors at once — it's typically the largest glass area feeding the darkest circulation space in the house. Clean it and the whole staircase visibly brightens; the numbers on how much light dirty glass eats are here.
FAQ
How do professionals clean stairwell windows?
From outside with water-fed poles, and inside with poles or towers — professionals don't put ladders on stairs either, which tells you everything.
What about the cobwebs before wet cleaning?
A dry duster head on the same telescopic pole, top corners first. Dry before wet, always — wet cobwebs smear.
The window is above a void two storeys down — robot placement?
Place it from the landing on the reachable part of the pane and let it drive to the rest. If no part of the glass is reachable from any floor, that's the rare true pole-only window.
The stairwell window went uncleaned because every option felt dangerous. With a robot that grips the glass so you don't have to, it's just another pane.