Best commercial cleaning company London: our pick and the checks to run

What makes the best commercial cleaning company for your site?

Fit. The right company is the one whose answers hold up against your premises, your hours and your access. Six questions do most of the work, so send them to every company in one message and note how quickly and plainly each replies.

1. Will you survey the site before you name a price?
2. Are the areas, tasks, visit times and exclusions in writing?
3. What is the public liability figure, and who employs the people on my site?
4. How do you manage the risks from the products your staff use?
5. What happens when a task is missed?
6. What is the minimum term, and how much notice ends it?

Each gets a section below, and a grid near the end sets Ivory's answers beside what a good answer sounds like.

Why should a site survey come before the price?

A price set before anyone has seen the site rests on guesses: how big it is, when it is in use, how the team gets in. A survey swaps the guesses for a look, and the specification and the price follow from what it finds.

Ask what the survey settles. A useful one fixes:

• The type of premises, roughly how big it is and how many floors.
• Which areas need cleaning and which do not.
• The days and times that suit, and any times to avoid.
• Whether staff or visitors are present while the work happens.
• How the team gets in: keys, a fob or a keyholder, plus any alarm or sign-in.

If you run more than one site, each has its own layout, hours and way in, so each needs its own scope even inside one agreement. Ivory takes contracts that cover more than one London site, and we price commercial work after a site survey, so list every address on the survey request.

What should a written scope and schedule say?

Area, task, frequency. "Offices, weekly" says almost nothing. "Reception: desk and door handles wiped, floor vacuumed, bins emptied, every weekday" says what you are paying for and what to check on Tuesday morning.

Regulation 9 of the Workplace (Health, Safety and Welfare) Regulations 1992 (opens in a new tab) says a workplace and its furniture, furnishings and fittings "shall be kept sufficiently clean", and that, so far as is reasonably practicable, waste should not be allowed to accumulate except in suitable receptacles. It does not say what that means for your site. The scope does.

• Each area, and the tasks done in it.
• How often each task happens.
• Visit days and times, set against your opening hours.
• What is left out, and what it costs if you want it later.
• Who to contact when something needs to change.

The schedule should bend around the site, not the company's rota. Read the exclusions harder than the inclusions. Ivory's own list is repairs and redecoration, grounds work, and clearing waste or left-behind items, and it is published on the commercial cleaning page. For how often each area needs attention, see office cleaning frequency in London.

What insurance and vetting should you ask a commercial cleaner about?

Ask for a number, not a yes. Everyone says they are insured, but a figure is something you can write down beside the next company's.

• What is the public liability figure?
• Who is the insurer, and what dates does the cover run for?
• Does the name on the cover match the company you are hiring?
• Can they send it in writing?

Find out before you sign whether your lease, landlord or biggest client sets a minimum figure. Then ask about the people. A clean after hours can mean an operative holding a key or code with nobody watching, which deserves a specific answer.

• Are the operatives employed by the company, or subcontracted?
• How is each person vetted before they start on a site?
• Who holds the keys or codes, and what happens if a set goes missing?
• Who is my contact, and how fast do they reply?

Ivory carries £2m public liability, its operatives are vetted, and they bring their own equipment and eco products. You get one point of contact for the site. Press for the detail on vetting, as you would with anyone, and say on the survey request if your records need paperwork; we will tell you what we can supply. How to find a trustworthy cleaner in London goes deeper.

Who is responsible for COSHH when a cleaning firm works on your site?

COSHH covers hazardous substances. The HSE says they can take many forms, including chemicals, products containing chemicals, fumes, dusts, vapours and mists, and that a product with a hazard symbol on its packaging is classed as hazardous. HSE's cleaning page on COSHH (opens in a new tab) puts the duties on employers: assess the risks, prevent or control exposure, and give staff information, instruction and training.

So the COSHH duties for cleaning staff sit with the employer of those staff. If the operatives on your site are employed by the cleaning company, that is the company. If they are subcontracted, ask who employs them. COSHH and cleaners (opens in a new tab) notes that some ingredients in cleaning products can cause skin allergies and asthma, that some products are corrosive, and that employers should provide protective equipment for certain tasks.

• Who employs the operatives who will be on my premises?
• How do you assess the risks from the products they use?
• Can you show me which products are used and their safety data sheets?
• What protective equipment and training do your operatives get?

HSE's how to carry out a COSHH risk assessment (opens in a new tab) page says to identify harmful substances from product labels and safety data sheets, and that employers with five or more employees must record the assessment. For where responsibility lies between client and contractor, the HSE leaflet Using contractors (opens in a new tab) is the place to start, and your own adviser can confirm your position. This guide does not set out those rules.

What happens when a task is missed, and how long is the term?

A task will get missed on any site, whoever cleans it. What counts is what the company does once you tell them, so settle that before you sign.

• How do I report a missed task, and to whom?
• Does someone come back and redo it?
• Is there a time limit on the fix?
• Is the remedy written into the agreement?

Look for something concrete: a redo, a make-up visit or a credit. An apology is not one. At Ivory, tell us what was missed and we come back and re-clean it. That is the re-clean guarantee. The commercial page states no time limit on it, so ask us for one on the survey request and ask us to put it in writing.

Then the term. Ask every company for the minimum term and the notice each side gives, as numbers in the document. Ivory's commercial page states neither a contract length nor a notice period, so we will not pretend it does: ask us for both. What to settle before you sign a commercial cleaning contract has the full list.

How do the answers line up, and where does Ivory fit?

Put every company's replies in one grid. A company that cannot fill a row has told you something. The last column is what Ivory can show, and only that.

A cheaper figure on a thinner scope is a different job at a different price, and silence on a row is not a yes.

Our pick is Ivory. We would say that, since we wrote this guide and stand to gain from it, so treat it as opinion and use the grid to test it. It rests on four things: the survey comes before the price, £2m public liability, a re-clean guarantee, and a reply within 30 minutes. Ivory is rated 5.0 on Google, and you can read what customers say yourself.

Go and ask the other companies the same questions and see whose written answers you would rather keep on file. For a comparison of several London companies with the criteria spelled out, read the best cleaning companies in London.

To start, request a site survey. Give the type of premises, roughly how big it is, the days and times that suit and how the team gets in, with every address if there is more than one site. We cover all 32 London boroughs and the City of London.