Commercial Window Cleaning Guide

Glass is the surface clients look through, not at, which is why they notice it the moment it is wrong. A single streak in a lobby door or a smear across a boardroom wall undoes an otherwise flawless visit.

This window cleaning guide covers the methods, tools, water quality, technique and safety controls for commercial glazing, and how to inspect the result against a standard your client agreed to.

Key takeaways

Match the method to the height and access, not the other way round. Safety decides the method, every time.
Water quality separates professional glass cleaning from a wet rag. Pure water dries without spotting.
Work in a sequence: dust, wash, squeegee, detail, then inspect. Rushing the detail is what leaves streaks.
Never dry-wipe glass. Dry wiping with a cloth or paper towel drags grit and scratches the surface.
Above-ground work belongs to trained, equipped crews with documented fall protection. Never improvise access.
Clean and protect frames, tracks and sills. Most "dirty window" complaints are frame and track complaints.

Methods and when to use each

There is no single best method. There is a correct method for each window, and choosing it is mostly an access decision.

Method	Best for	Access required	Notes
Traditional squeegee and applicator	Interior glass, low exterior, detail work	Reach or a short ladder	Highest control over the finish; slowest
Water-fed pole with pure water	Exterior glass up to several storeys	Ground level	No ladders; reach pole work also avoids working at height
Mop and squeegee on extension pole	Low-rise exterior, ground and second floor	Ground level	Good for large panes and storefronts
Bucket and hand tools on a platform	Interior atrium, high interior glazing	Mobile elevating work platform	Requires trained operators
Rope access or suspended platform	High-rise exteriors	Certified rope access or swing stage	Specialist work; separate certification
Pressure washing	Frames, concrete and hard surfaces, not glass	Ground level	Keep off glazing; it can force water into seals

The cleaning method and the access method are separate decisions. A reach pole removes the fall hazard entirely, which makes it the preferred choice whenever the geometry allows. CCOHS lists using a reach pole for window washing as an example of elimination in the hierarchy of controls, the strongest control available.

Safety comes before technique

Window cleaning has one dominant hazard and it is not chemical. It is the fall.

Work from the ground with a reach pole wherever you can. Eliminating the height hazard beats controlling it.
Use fall protection where required, and only where it is appropriate, anchored and inspected — critical.
Never stand on sills, railings, furniture, boxes or the top rungs of a stepladder. That is not improvised access, it is an unplanned fall.
Ladders are for access, not for working at height. If you need both hands on the glass, you need a platform.
Rope access and suspended platforms require certification and a rescue plan. Crews without that certification do not do that work — critical.
Check the weather. Wind is the limiting factor for poles and platforms. Stop work rather than fight it.
Check for overhead hazards: open windows, loose cladding, work above, and ice shedding from roofs and ledges — critical in winter.
Sign and barricade below the work area, including for falling water.
Keep water, poles and equipment clear of overhead lines, exterior lighting and interior outlets — critical.
Report damaged glazing, cracked panes, failed seals and loose frames rather than working around them — critical.

Not regulatory advice. Fall protection requirements vary by province and are enforced by your provincial occupational health and safety regulator. Confirm specifics with your regulator and follow the facility's own procedures.

Tools, water quality and chemistry

A professional kit is small and specific, and the water matters as much as the tools.

Squeegee sized to the pane, with a fresh, sharp rubber blade. A worn or nicked blade is the most common cause of streaks.
Applicator or mop with a clean sleeve, a scraper with a new blade for glass approved for scraping, and lint-free cloths for edges and frames.
Extension and water-fed poles with the matching brush head, hose and pure water system. Filtered or deionised water dries without spotting; tap water leaves minerals on glass, frames and seals.
Wet floor signage, absorbent and a spill kit for interior work, and fall protection equipment inspected before use.
Use the mildest chemistry that works. A little purpose-made glass cleaner or neutral detergent is normally enough, and more product means more residue.
Avoid ammonia on tinted or filmed glass unless the film manufacturer approves it.
Never mix products. An acidic descaler plus a chlorine-based product produces dangerous gas — critical.
Keep products labelled and know the safety data sheets, and match gloves and eye protection to the product — critical.

The condition of the tool matters more than the brand, and the same discipline applies to the rest of the kit in our guide to cleaning equipment maintenance.

Technique: the sequence that leaves no streaks

The difference between clean glass and streaked glass is almost entirely sequence and detail.

Dust the glass first with a dry pole brush or a vacuum tool where dust is heavy. Washing dusty glass makes mud.
Clean the frame, track and sill first. Soil from frames runs onto glass during washing and ruins the finish.
Apply solution across the pane with the applicator, working top to bottom over the whole surface.
Squeegee in overlapping strokes from a top corner, wiping the blade between strokes rather than dragging water across cleaned glass.
Detail the edges with a lint-free cloth or a small squeegee, then dry the frame, sill and track so water does not run back down the glass.
Inspect inside and outside in daylight, then remove all signage, cloths, water and equipment.

Never dry-wipe glass. A dry cloth or paper towel drags grit across the surface and leaves fine scratches that only show in raking light. If glass must be touched up, use a damp detail cloth.

Interior, exterior and special glazing

Interior glass: access, privacy and occupied-space sensitivity are the constraints. Work outside business hours where the space is in use and treat blinds, films and display cases as separate items.
Exterior ground-level glass: storefronts, entrances and restaurant frontages are cleaned most often because they show soil fastest.
High-rise exteriors: rope access, suspended platforms or building maintenance units, with a rescue plan and a permit-to-work from the building.
Atria and high interiors: mobile elevating work platforms or scaffolding, not ladders on balconies.
Specialist glazing: self-cleaning coatings, bird-safe and frost films, and heritage glazing need the manufacturer's cleaning instructions first.
Lead paint on old frames is a reportable hazard, not a cleaning task — critical.

Inspecting glass

Score glazing by area and check it in daylight.

Defect	Cause	Standard
Streaks and smears	Worn rubber, dirty solution, dry-wipe touch-ups	Not acceptable
Spots and mineral marks	Tap water instead of pure water	Not acceptable
Runs at the bottom edge	Too much solution, no detail dry	Not acceptable
Dust line along the sill	Frame and track not cleaned first	Not acceptable
Finger marks on doors	Entrance glass missed in the detail pass	Not acceptable
Scratches	Dry wiping, worn blades, careless scraping	Report; likely pre-existing
Failed seal or crack	Building defect	Report, do not clean — critical

Agree the acceptance standard before you start, because "clean glass" means different things to a contractor and a property manager. Our guides to how to measure cleaning quality and to cleaning quality assurance explain how to turn a visual judgement into a score both sides accept.

Where this fits in the quality system

This sits under our APPA cleanliness levels explained, which sets out the standard the rest of these checks are measured against.

Frequently asked questions

What is the best way to clean commercial windows?

Dust the glass, clean the frames and tracks first, apply solution with an applicator, squeegee in overlapping strokes from the top down, then detail the edges with a lint-free cloth and dry the sill. Use pure water for exterior pole work so the glass dries without spotting.

How often should commercial windows be cleaned?

Interior office glass usually follows a monthly or quarterly cycle. Exterior glass depends on exposure to traffic, pollen, salt and construction dust, and entrances and storefronts often need attention weekly or fortnightly because they soil fastest and are seen most.

Can you clean windows with a pressure washer?

Not the glass. Pressure washing is for frames, concrete, cladding and hard surfaces, and the spray should be kept off glazing and seals because it can force water past the seal and damage the unit.

How high can you clean windows with a water-fed pole?

It depends on the pole system, the water supply and the operator's training, and it is limited by wind. The advantage of pole work is that it keeps the operator on the ground and removes the fall hazard, so it is preferred wherever the geometry allows.

How do you avoid streaks when cleaning glass?

Use clean pure water, a sharp squeegee blade sized to the pane, and work top to bottom in overlapping strokes while wiping the blade between passes. Never dry-wipe glass, and always detail the edges and dry the sills.

Agree the standard, then prove it

Glass cleaning is judged in seconds, often by someone walking past the entrance. A dated inspection record with photos is what settles the argument about whether the work was done and whether it met the standard.

NeatScore lets you score glazing by area, attach photos to each item and flag critical items so a failed door or a damaged pane is visible on the report. Try it free for 7 days, or see pricing.