Windows: the long version

We have cleaned commercial glass for years with a dedicated window crew — its own trucks, pole systems, calendar and route. This section is what a building owner should understand about their glass before hiring anyone to clean it, including us.

Glass types, and why the crew asks before they touch it

Not all glass is the same, and the crew's first question on a new building is what they are looking at, because the method changes with the answer. What follows is the customer's version: enough to know what you have and why it matters. The technique details are the crew's, and they are trained on them.

• Plain float glassOrdinary window glass, common in older buildings and interior partitions. The most forgiving to clean and the easiest to scratch with grit, so it is washed before it is squeegeed, never dry-wiped.

Plain float glass

• Tempered safety glassHeat-treated to break into pellets rather than shards; required in doors, sidelights and anything near the floor. Look for the small etched stamp in a corner. Its surface needs more care than plain glass, and the crew treats it accordingly.

Tempered safety glass

• Laminated glassTwo layers with a plastic interlayer, used for security and sound. Cleans like plain glass on the surface; the edges are the vulnerable part and are kept dry.

Laminated glass

• Coated glassMost commercial glass installed in the last twenty years carries a thin metallic coating for heat and glare. On some units the coating is on an exposed face. It looks like ordinary glass and is not; the crew identifies it and uses the method that suits it.

Coated glass

• Double and triple pane unitsTwo or three panes sealed around a dry gap. Cleaning reaches only the outer faces. If something is between the panes, the seal has failed — see below.

Double and triple pane units

• Storefront and curtain wallLarge panes in aluminum frames; the frames, gaskets and drainage holes are part of the job. Grit left in a track ends up back on the glass on the next windy day.

Storefront and curtain wall

Interior versus exterior

They are two different jobs done by the same crew, and they are scheduled differently.

Exterior glass is weather: road film, rain splash, pollen, bird droppings, sprinkler overspray and, in winter, salt haze. It is cleaned from the ground with poles and squeegees on low buildings and with a water-fed pole on taller ones, on a route that runs regardless of what is happening inside.

Interior glass is people: fingerprints on doors, the haze that builds on conference-room partitions, the dust that settles on sills and on the inside of curtain wall. It is squeegee work room by room and has to fit around tenants, so it is done before opening, after close, or a floor at a time.

Most buildings need the exterior more often than the interior, with one exception: entrance and lobby glass, which is touched all day. On a nightly janitorial account the crew de-prints the doors and lobby glass every visit, which is why interior routes can be less frequent.

Height and access

How high the glass is decides how it is reached, and how it is reached decides both the price and who is allowed to do it.

• Ground floor. Poles and squeegees from the sidewalk. Fast, and the same on every visit.
• Two to five stories. A water-fed pole. Purified water is pumped up a long, light pole to a brush head; the brush scrubs and the water rinses, and because that water carries no dissolved minerals it dries with no spots and needs no squeegee. Nobody leaves the ground, nothing is parked on your lot, and a five-story elevation is done in a morning.
• Above the pole's reach, or awkward elevations. A boom lift or, on a tower, rope access. Both are quoted separately, need the space and the paperwork, and are done by people trained and insured for it. If a building needs a lift, we say so. We do not put a ladder against a fourth-story window.
• Interior heights. Atriums, stairwells and lobby glass with poles, and with a lift where the space allows and the schedule can close it.

How often glass really needs cleaning

Time is not what dirties glass; exposure is. Three things decide the honest interval for any pane:

• Traffic and spray. Glass facing a busy road, a bus stop or a parking lot picks up road film and, in winter, salt haze. Monthly is normal for a storefront; a road-facing office elevation may need quarterly while the courtyard side is fine twice a year.
• Water. Irrigation heads that hit the glass, rain splashing off a hard surface below a window, and overspray from a neighbor's sprinkler all leave minerals that etch if they stay. Fix the sprinkler; it is cheaper than the extra cleaning it causes.
• What the glass is for. A showroom sells cars through it; a clinic's waiting room looks at it all day; a warehouse office looks out of it twice a week. The interval should match what the glass is doing for the business.

The usual answers: storefronts monthly, weekly for a showroom's front glass; office exteriors quarterly, with the entrance elevation more often and a sheltered elevation less; interiors twice a year with nightly touch-ups on doors and lobby glass; and post-construction once, properly, before the owner sees it — see post-construction clean. We walk all four sides at the proposal, because they are not equal and you should not pay as though they were.

Hard water and mineral staining

The white, cloudy spots that will not wipe off are minerals — calcium and magnesium left behind when hard water dries on glass. The water in this region is hard, so any glass hit by irrigation, by rain running off a limestone sill, or by splash from a hard surface below will build a deposit. Left alone the deposit bonds, and then it etches, and at that stage it is in the glass rather than on it.

What we can honestly tell you: a fresh stain comes off; a stain that has been there for years may be permanently etched, and the only fix is replacement or a specialist restoration that is a different service at a different price. We assess pane by pane at the walkthrough, mark which is which, and quote only what can actually be fixed.

The prevention is cheap and worth more than the cure: adjust the sprinkler heads so they do not reach the glass, and put the glass on an interval that clears deposits before they bond.

Dirt, fog or water lines between the panes

This is the question we are asked most, and the answer is one we would rather give straight than dodge. A modern commercial window is a sealed unit: two, sometimes three, panes sealed around a gap that is dry and usually gas-filled. If you can see fog, a water line, a film or dirt inside that gap, the seal around the unit has failed. Moist air has got in, condensed on the inner faces, and left a residue as it dried and re-formed, day after day.

Nothing can be cleaned there. The dirt is on faces of glass that no cloth, no pole and no chemical can reach without taking the unit apart — and a unit taken apart has to be re-manufactured. A failed seal means the sealed unit needs replacing, and that is a glazier's job, not ours.

What we do is tell you which units have failed, pane by pane on the route report, so you can plan the replacement instead of paying anybody — including us — to "clean" something that cannot be cleaned. We would rather drop that pane from the route than charge you for it.

What a properly cleaned window looks like

A wiped window looks clean at 5 pm and shows everything at 8 am when the sun comes across it low. A cleaned window does not. Here is how to check any window cleaner's work, including ours:

• Low sun, from inside. No streaks, no arcs, no haze. Streaks mean a dirty blade or a rag; haze means a product that leaves residue.
• The corners. Clean to the frame, with no crescent of grime where the blade did not reach.
• The sill and the frame. Dry, and the same color as the rest of the frame. Drips on the sill and grit in the track mean the frame was not part of the job.
• The bottom edge. No line of water or dirt where the squeegee stopped short.
• A week later. Exterior glass done with purified water stays clear for the interval; glass done with tap water shows spots after the first rain.

If a company's work fails that check at 8 am, it was wiped. If it passes, it was cleaned. The difference is what you are paying for.

What to expect

• Walkthrough. We count panes and elevations, identify the glass, note the access, look for hard-water staining and failed seals, and see where sprinklers and road spray hit.
• Written scope and proposal. Interior and exterior listed separately, each with its interval by elevation, specialty work called out, and a flat price per visit or per year. Multi-site programs get one schedule and one contact.
• The route. A date and a time window that fits your tenants; the truck arrives with everything on it; you get a completion note. Weather moves an exterior date and we tell you beforehand.
• Ongoing. The route repeats without you having to remember it. Failed seals and etched panes are reported pane by pane, so what you pay for is what can be cleaned.

power washing