What Should Building Managers Ask Before Hiring a Window Vendor?

The Short Answer

Before you hire a commercial window vendor, ask six things: for a certificate of insurance naming your building as additional insured, for an itemized scope that states exactly what glass and how many stories are included, for their high-access safety plan and equipment, for the water method they use on the exterior, for their guarantee if the work does not hold, and for references at properties like yours. A vendor who answers all six in writing is a professional. One who dodges any of them is a liability you would be signing for. The rest of this guide is why each question matters and what a good answer sounds like.

Why Does a Certificate of Insurance Matter So Much?

This is the one that can actually cost you. If an uninsured cleaner falls off a ladder on your property, or drops a pole through a storefront, the claim can land on your building's policy, not theirs. That is why a certificate of insurance, or COI, is non-negotiable for commercial work. Do not accept a verbal "yes, we're insured." Ask for the certificate in writing, ask that your property be listed as additional insured, and confirm it covers general liability and, for any crew working at height, workers' compensation. Glide is insured across every market we run, and a certificate of insurance is available on request before the first visit. A vendor who cannot produce one same-week is telling you something.

What Should the Scope Actually Spell Out?

Commercial quotes go sideways when the scope is one vague line. "Clean the windows" does not say whether that is exterior only or both sides, whether it includes the upper floors or just what a ladder reaches, or whether frames, tracks, and entry glass are in the price. Get it itemized. A clear commercial scope names the elevations, the story count, interior versus exterior, and the frequency. That is also what lets you compare two bids honestly, because a low number that quietly excludes the third floor is not actually the lower bid.

How Do They Handle High-Access and Tenant Disruption?

Above the second floor, method is a safety question, not a preference. Ask how they reach the upper glass and what keeps the crew and the public safe while they do it. For much of mid-rise commercial work the safest answer is a water-fed pole: the technician stays on the ground and cleans several stories up from below, which removes the ladder-and-harness risk over walkways and entrances entirely. Also ask when they work. A good commercial vendor cleans around your tenants, early mornings, off-peak hours, or a set recurring slot, so customers are not stepping around wet ladders at your front door.

What Water and Method Should a Commercial Vendor Use?

For exterior work, ask whether they use purified water. Glide cleans with a deionized, purified water-fed-pole system, and the reason it matters on a commercial facade is simple: purified water has had its dissolved minerals stripped out, so it dries without spotting. Ordinary tap water leaves the same mineral film on a glass tower that it leaves on a shower door, which on a south-facing storefront in the Arizona or Texas sun becomes visible within days. Purified water also lets the crew clean multiple stories from the ground safely. If a vendor cleans a four-story exterior with a bucket of tap water and a squeegee, ask how they plan to reach it and why the glass will not spot.

What Happens If the Work Does Not Hold?

Weather is the honest complication of exterior glass. A storm two days after a clean can undo the work, and the difference between a professional vendor and a cheap one is what happens next. Ask directly: if it rains or the glass spots within a few days, do you come back? Ask what the guarantee covers and how you request a touch-up. You are not trying to catch anyone out. You are confirming there is a named process instead of a shrug, because on a recurring commercial account a no-questions touch-up policy is worth more than a few dollars off the quote.

What References and Track Record Should You Ask For?

Finally, ask who else they clean for and how long they have been doing it. References at properties like yours, an office park, a retail strip, a medical building, tell you more than any sales sheet. Glide carries more than 4,400 Google reviews at a 4.8 rating, is registered as an LLC in five states, and can offer same-day availability when a listing walk-through or an inspection lands on you with no notice. Those are the kinds of specifics a serious vendor can produce on request. If a company cannot point to a single comparable account, let them earn a smaller job first.

The Short Version

Six questions protect your building: the certificate of insurance, the itemized scope, the high-access plan, the water method, the guarantee, and references. The vendor worth signing answers all six without flinching, which is exactly how we structure a commercial window cleaning bid: in writing, itemized, insured, and scheduled around your tenants. Ask the six questions of anyone you consider. The right answers are not hard to give, and the wrong ones are cheap for a reason.