Cleaning Exterior Windows: Do It Yourself or Hire It Out?

The decision is reach, not dirt. Glass you can stand beside — the ground floor, a glazed door, anything an extension pole reaches while both feet stay on the ground — is a household job, subject to the rules the glass itself imposes. Once a ladder is the only way to a pane, the job has stopped being a cleaning decision and become an access decision, and access is where the injuries are. Washington’s own safety rules for paid work start at four feet.

The second half of the answer is less obvious. Window washing is one of the services Washington does not require a contractor to register for, so the standard hiring advice — check the registration — does not apply here. The checks move to insurance, business licensing, and who carries the cost of a fall.

The glass does not care who holds the squeegee

Cardinal IG, which makes insulating glass units, publishes a technical service bulletin on glass cleaning. Its first instruction is not about soap. It is to check whether the glass carries an exterior coating applied by the glass manufacturer, and to review that manufacturer’s cleaning procedure, because, in the bulletin’s words, “certain glass cleaning products may harm these coatings.”

Written for whoever holds the tool, homeowner included:

• A mild, non-abrasive window cleaning solution, applied to glass soaked with clean water, and removed with a rubber squeegee, a cloth or a paper towel. Abrasive solutions and abrasive materials are on the don’t list.
• No metal blades. The bulletin is blunt that this is the trade’s own recurring error: “one of the common mistakes made by non-glass trade people, including glass cleaning contractors, is their use of razor blades and other metal scrapers on a large portion of the glass surface.” It then states that metal blades should never be used to remove material from glass, and that its warranties do not cover glass scratching.
• Clean one small window first and check that no damage occurs before working across the rest.
• Keep solutions off the window components. Two separate instructions — dry all cleaning solution from the sealants, gaskets and frames, and do not allow water or cleaning solution to remain on glass surfaces or window components — point at the same habit: rinse, then dry, rather than wetting the whole wall and walking away. Driving water behind cladding and finishes is its own subject.
• Not in direct sunlight, on tinted or coated glass.
• Nothing leaning against the glass, and no dirt or residue left on it for an extended period.

Two further points from the same bulletin decide what a disappointing result means. Residue that can be cleaned from the glass is not a defect, and neither is residue visible only when the glass is wet; the bulletin says such a condition should not prompt replacement. And the industry’s own cleaning recommendations, published jointly by the National Glass Association, the Glass Association of North America and the International Window Cleaning Association, are what the bulletin sends its readers to for the full procedure — covering commercial and residential glass.

Where the household job ends

The federal safety institute is unusually direct about the setting. NIOSH’s ladder safety page records 161 workplace deaths and 22,710 workplace injuries from ladders in 2020, then adds the sentence that matters for a homeowner: “Not all ladder injuries happen at work. Many ladder injuries happen at home.”

Its five causes are worth reading as a description of window cleaning rather than of construction. The first is an incorrect set-up angle, which NIOSH says accounts for about 40 percent of ladder-related injuries, the mechanism being a ladder sliding out at the base; it gives the working angle as about 75 degrees. The fourth is improper use: overreaching, carrying objects up or down, and applying excessive force. The fifth is that individual ladder users rarely receive any training in the first place.

Reaching sideways to a high pane, holding a squeegee and a bottle, and pushing hard enough to shift a film of grime combines three of those five in one motion, on a ladder. That reading of the list is this publication’s, not NIOSH’s — but the list is NIOSH’s.

The pillar covers the four parts of a window and how to tell which one has failed. This page stops at the point where the answer to “should I clean it myself” becomes a question about a ladder rather than about glass.

What Washington requires of a crew

The state writes the access rules down, and they bind the employer rather than the household. The fall-protection rule requires an employer to ensure that fall arrest, fall restraint or positioning systems are provided and used where employees are exposed to fall hazards of four feet or more to the ground or a lower level from a walking or working surface with an unprotected edge. Portable ladders have a chapter of their own, and its use rules are equally employer-facing: employees must keep at least one hand on the ladder while climbing, face it, not carry an object or load that could cause a loss of balance, and single-rail ladders are not to be used at all.

A crew that arrives with more equipment and takes longer than a homeowner expects is usually the rule showing, not caution for its own sake. The flip side is the one worth remembering: every one of those provisions protects an employee. A homeowner on their own ladder has none of them.

The Washington check that is different here

The hiring advice that serves for roofing or siding does not transfer. The Department of Labor & Industries’ consumer publication on hiring lists the work that requires a registered contractor — anything that “adds to or subtracts from real estate”, advice or consultation on a construction project, developing residential property — and then lists services for which registration is not required: “Gutter cleaning. Pruning or lawn care. Window washing.”

The specialty list behind that statement is consistent with it. L&I regulates 63 contractor specialties for registration purposes, and the code that defines them contains no window-cleaning classification. The only entries that mention windows are about installing and repairing things — window awnings and exterior screens, window coverings — not about cleaning them. Pressure washing, by contrast, is a specialty in its own right, defined as using the force of pressurized water to clean and prepare surfaces for a protective, decorative or functional treatment on a commercial or residential structure. A quote that widens from glass to siding or driveway washing is no longer a window-washing quote, and the registration question has to be asked again.

So the registration check does not settle the question, and that is not the same as saying a window-washing business is uninsured. What registration carries with it — a surety bond, general liability insurance, a Washington business license — has to be established by asking instead: for the business license, for a certificate of liability insurance, and, where the outfit has employees, for evidence of workers’ compensation coverage.

The department attaches a warning to the gap. Its consumer guide states that a person who hires someone who is not a registered contractor “could be considered that person’s employer, with wage, tax, workers’ comp, safety, and record-keeping requirements”, and adds that most homeowner policies do not cover workers, so an injury on the job can land on the property owner. That is the practical argument for a business with its own insurance over the cheapest cash price — not a comment on anyone’s workmanship.

What the quote should state

• Which panes, by floor and by side of the house, and whether glazed doors and sidelights are included.
• The access method for anything above the ground floor.
• The glass: whether it carries an exterior coating, and what the cleaner proposes to use on it.
• Screens: removed, cleaned and rehung, or left in place.
• Water: the source, and where the rinse water goes. Washing glass produces wash water, and that question is its own subject.
• Insurance: a certificate of liability insurance, and workers’ compensation if there are employees.
• Exclusions and weather: what happens to the price if a scheduled day is wet or windy.
• Damage: who is responsible for a scratched pane or a marked frame, stated before the work starts.

Comparing two of those side by side is its own exercise, and the guide to comparing written scopes sets out how.

When it is not a cleaning job at all

Three symptoms look like dirty glass and are not. Fog or a milky haze between the panes is a failed sealed unit, and no cleaner reaches it. Water standing in the track or at the interior sill after rain is the frame’s drainage path, not the glass. Staining, blistering paint or soft plaster at the interior perimeter after rain is water arriving behind the frame, which the pillar treats as a wall question before a window question. All three are sorted there, and the last two are not improved by washing the outside of the pane.

The next useful action

Walk the exterior in daylight and count the panes that sit above anything you can reach with both feet on the ground. Note whether the glass carries a coating, from the unit’s label or by asking who supplied it. Then the decision is mechanical: bucket and pole for what you can reach with both feet down, and a call for what you cannot. Clean coated glass in shade, and keep the hose off the seals and frames.