A deep clean is not a better version of the nightly clean. It is a different list of tasks, done at a different interval, with different equipment, in access windows the nightly round does not get. Treating it as an upgrade is how buildings end up paying a higher monthly rate and still having the same dirty high level, because nothing in the specification actually changed.
What is on the list, and why the round never reaches it
Carpet extraction, hard floor scrubbing and refinishing, high-level dust above reach, light fittings and diffusers, internal glass, kitchen and washroom descaling, and the underside and backs of things. Every one of them needs either equipment that does not live on a trolley or a space that is out of use, and the nightly round has neither.
It is priced as a project, and that is the useful part
Because a deep clean is a defined list against a defined area, it can be quoted as a fixed price and compared between contractors properly. That is unusual in this trade, and it is worth taking advantage of by asking for the list itself rather than for a figure.
Two published figures in this record touch it
One company publishes a deep-cleaning and specialty-services uplift per square foot on top of its standard rate, and one publishes a floor waxing and polishing rate per square foot. Both are quoted from their own pages and dated here. They are the whole of what this market puts in writing about periodic work, which tells you how much of it is negotiated rather than published.
Interval beats intensity
A building on a sensible deep-clean interval needs a lighter deep clean each time and keeps its floors and surfaces longer. A building that waits until something looks bad buys a heavier job at a worse price under time pressure. The interval is the decision; the price mostly follows from it.
Questions people ask about deep cleaning commercial
How often should a commercial building be deep cleaned?
It follows from traffic, floor type and what the building is for. What matters more than the number is that the interval is written into the contract, because an unnamed periodic task is an optional one.
Is a deep clean included in a monthly rate?
Sometimes as an allowance, often not at all. Ask which, because a monthly figure that quietly includes an annual deep clean and one that quietly excludes it look identical on a quotation.
Can it be done while the building is occupied?
Parts of it. Anything involving floor finish or high-level access generally needs the space empty, which is why the access window belongs in the specification.
Is it the same contractor as the nightly clean?
Usually, and it does not have to be. What matters is that it is priced as its own project with its own task list rather than described as included.