Myth busting Coronavirus deep cleaning

How to ensure your building is really clean, hygienic and safe to reopen (and to retain staff and customers’ confidence in this)


It’s clear that the cleanliness of your building has never been more important than it is now.


We simply won’t go from being on hygiene lockdown to accepting the poor standards of cleanliness that have prevailed, in all sectors, in the UK for a number of years.


If there’s one thing you must know, though, it’s this: you cannot disinfect your building without it first being effectively cleaned


“Disinfection is a process that reduces the number of micro-organisms to a level at which they are not harmful and is only effective if the surface is thoroughly cleaned with a detergent solution beforehand” (NHS)


Many building owners have been engaging in various “COVID-19 killing” cleaning activities, but have they been hoodwinked? Do building operators, and even their contractors, know the difference between cleaning, sanitising and disinfecting? How can you be certain that your buildings have been effectively deep cleaned and disinfected before you reopen them after lockdown?



First, why have cleanliness standards been poor historically?


Cleanliness (the outcome) has always been valued, at least ostensibly. Yet cleaning (the delivery method) has not.


Therefore, budgets have been cut, shortcuts have been taken, and outputs of cleaning (whether in-house or outsourced) have been poor.


The link between cleanliness and safety (including in hygiene) has also not been communicated well. Cleaning should be considered your first line of defence in your staff and clients’ health and safety – from viruses to slip safety to mental health.


This is definitely not to criticise cleaning contractors: I have very rarely ever seen a contract specification that is not being met – but there is often a vast gap between what the contract says must be delivered (cleaning) and what the client’s ideal outcome is (cleanliness). If you pay a bronze price you won’t get a gold standard. Saying that, standards delivered have been poor for some time, so these types of company might not be able to deliver an effective deep clean to get you back up to standard.


We must recognise that this chronic underinvestment has led to generally poor outcomes. This often isn’t exhibited by “filthy” standards but rather by “evenly poor” standards. Most floors, for example, probably don’t look dirty to a layperson until you show them what the colour of it really is if it is cleaned effectively.


If buildings are not clean, they are not hygienic and they are not safe.



What is clean?


You’re probably thinking that your buildings look okay. And yes, they may well look okay. But just as the Coronavirus cannot be seen, many other types of contamination are invisible to the naked eye, too.


Imagine you were being wheeled in for an operation and you saw the surgeon spitting on his handkerchief and wiping down the scalpel he was about to use to cut into you. That handkerchief “looks” clean, but it definitely is not!


How surfaces look aesthetically is only one part of the puzzle of achieving an effective cleaning regime, and therefore the outcome of a hygienically clean and safe building.


It’s possible to clean a commercial kitchen floor, for example, with a mop and bucket with fresh water. Afterwards, it may look slightly cleaner aesthetically than it did before. But has the contamination been removed, have any germs been removed, have any residues that may make the floor slippery been removed? You’ve cleaned it, but you haven’t cleaned it effectively.


There are three key metrics that you need to be aware of. One is subjective and two are 100% measurable


1, Aesthetics / feel / odour


Do surfaces look and feel clean? Can you smell contamination?




As mentioned above, often we see surfaces that are evenly dirty so unless you have knowledge of what clean really looks like, you may feel they are ok. And dirty builds up slowly. I use the analogy of your wedding suit: 5 years after your wedding you might not fit into this, but you probably don’t feel like you’ve gained much weight because it happens very gradually over a long period of time. Dirt building up on a surface is the same.


You need to figure out what true cleanliness is on your surfaces and use that as a benchmark to maintain.




I recall visiting a theme park and looking at a restaurant area where they had a vinyl floor. It looked clean. But, when you started walking over it, your feet were sticking to the floor because of the level of grease build-up.


You can see this in all sorts of other environments as well. Think of pub or nightclub carpets, for example: they may look clean, but clearly they’re not clean if they are sticky!


Any contamination on or within a surface will act as a magnet for further contamination to build up, too.




Smell is very visceral to building users, and it’s likely they will notice this before anything to do with aesthetics.


A clean, crisp smelling in the air will give people the confidence that you are doing what you need to do to keep the environment clean.


Don’t take this to the extreme though, and plug in fragrance, producing devices in every room without actually doing the cleaning as well. Masking the problem doesn’t make your building clean or safe – it just gives a false sense of security.



2, Hygiene


There is a difference between looking clean and being hygienically clean. You can test this using various different methods to ensure that you are actually cleaning the surface and removing all bacteria from it.


Again, going back to our mop and bucket with also example, it might be that that surface looks cleaner after we’ve mopped water on it, but if we were to test the hygiene levels, before and after, it would probably have little to no difference at all.


And, crucially, a sanitiser or disinfectant chemical may also be totally ineffective. More on that below.



3, Slip safety


This relates only to floors. As with hygiene, a floor can appear clean to the naked eye, but actually have, invisible, or ingrained contamination within it. Any contamination covering of within the pores of a floor will have an effect on its slip resistance. Given slips are the biggest cause of injury and insurance claims in most sectors, this is a valuable measurement to get right.


Measuring the slip resistance of a floor will give an excellent indicator as to how clean it truly is. If it’s not a smooth surface but is slippery when wet, there is probably some kind of contamination on it.



I would strongly advise that you need to consider all three aspects. Firstly, for your own due diligence so you have done everything you can to provide a clean, hygienic and safe environment for staff and customers. But secondly from a perception perspective: if you don’t achieve on all three points, building users will notice.



What do you need to do?


I’ve given you the three metrics you need to consider. But how should you go about delivering the outcomes that you want?


It feels as if every man and his dog are now saying they can kill the Coronavirus. In reality, there is no single process that has been proven to an international standard to kill the virus from a surface. We have a very good idea, but testing is still being done to confirm this 100%.


There are, however, methods that Public Health England for example, have signed up to, which include physical cleaning of touch points using certain chemicals certain processes, certain PPE, etc. This is a clear signpost on how you should be dealing with things from an infection control perspective.


However, as already stated, you cannot kill of germs or viruses without effective deep cleaning first.



It’s vital that you understand the three types of “cleaning” as relates to this subject:


Cleaning is the removal of soiling, whether visible of invisible, from a surface


Sanitising is the reduction of bacteria and germs


Disinfection is the removal of bacteria and germs


You can sanitise a surface without necessarily cleaning it first, or indeed you can have one product or process which does both (e.g. your Dettol spray at home). But you cannot disinfect without thoroughly cleaning first, so not every all-in-one process will necessarily work.


So, if you are looking to ensure that germs are removed, you first need to have a thoroughly clean surface.


Whilst if your building has been closed, the virus will not be there, as soon as you open up again there will eb the chance of the virus coming in. If your surfaces are not clean, you will not be able to remove that virus with disinfection, you’d only be able to reduce it with sanitisation.


In summary, it’s important that you have a thorough deep clean if you want to disinfect.



Every man and his dog may be doing “it”, but is “it” effective?


Many companies, either seeking to self-deliver or engaging with third parties, are trying to clean, and try to reduce the risk of the virus. But are the methods employed truly effective?


No doubt you’ve seen many photographs or videos of cleaning operatives, dressed up in huge amounts of PPE and looking (as a industry friend said to me), like “Ghostbusters”. Is this approach actually working?


As with other aspects of this topic, the devil really is in the detail.


Firstly, you need to understand if you want your building to be sanitised (to reduce germs and bacteria) or disinfected (to remove germs and bacteria). I suspect you want the latter.


So, straight away, sanitising is out of the window when it comes to an initial requirement to unlock your building. (Once open, regular sanitisation can absolutely play a role).


When it comes to disinfection, three methods tend to be used:

  • Physical cleaning of touchpoints
  • Fogging
  • Electrostatic spraying


Let’s initially explain the difference between fogging and electrostatic spraying. The two are often confused, and even some contractors might not know the difference!

  • Fogging is atomising a chemical to apply it as a mist directionally
  • Electrostatic spraying is a method of applying a coating, cleaner, disinfectant, or other liquid, that involves applying an electric charge to a liquid in order to get it to fully cover a surface. The charge acts as a magnet to a surface but also ensures that the liquid doesn’t stick to itself either, so you get full surface coverage


The principal difference, therefore, is that, even if both methods were equally diligently applied, fogging can miss areas whereas electrostatic spraying will ensure to cover all surfaces.


Fogging only – pros and cons


There are companies solely providing fogging. If you just do this, you aren’t cleaning anything and therefore it’s highly unlikely that the process will kill bacteria, particularly if surfaces are very contaminated.


On the plus side, with operatives wearing full PPE and not physically needing to touch surfaces, the delivery risk is perhaps lower than physical cleaning.


It isn’t cleaning a surface, and therefore if a surface is very dirty, this method won’t have the desired effect. Moreover, it is directional. It’s easy to miss a spot using this method. Yet contractors are going in and charging large amounts of money just to do this. I would personally be wary of this approach.



Electrostatic disinfection only – pros and cons


This is much more effective than fogging in one respect, because the electrostatic charge clings to surfaces and therefore, it’s much, much more difficult for any areas to be missed. So, this will give you a better chance of achieving the right end result.


However, again, unless this is coupled with some physical cleaning for a cleaning process, it’s unlikely to be fully effective on every single surface particularly areas where dirt is present.


“Electrostatics provide no mechanical cleaning action, i.e., they do not remove physical soil. Rather, the electrostatic device is used to disinfect mechanically pre-cleaned surfaces.” (Bunzl)


As with fogging, the protection provided by PPE is great. As with fogging, I’d be very wary of solely doing this.


“There is no evidence that spraying or fogging rooms or surfaces with disinfectants will prevent infections more effectively” (Centers for Disease Control and Prevention – USA)



Physical cleaning only – pros and cons


Public Health England’s guidance is based on physical cleaning. There is no published government guidance on fogging or electrostatic spraying. For that reason alone, I’d suggest you must think very carefully about choosing any service that doesn’t include a thorough physical clean.


This will be effective up to the government’s standards, provided you do it with the right level of diligence and that you follow the process of clean > disinfect.


A downside is that to clean and then disinfect, you do physically need to touch every part of a surface, so huge diligence is required, plus the risk to operatives is arguably greater. The risk of human error is rife.


A risk is that many contractors’ cleaning processes (you’ll have gathered in the context setting part of this article) often leave a lot to be desired. Again, if you’re not cleaning effectively, you cannot disinfect.



A two-step process is needed


Overall, I believe that:

  1. if you don’t have a two-step process; and
  2. if you don’t start that process with an effective deep clean

…you’re wasting your time.


If for example, you were travelling on the train and your tray table was grubby, you’d pull out a disinfection wipe. Your perception is that the wipe will both clean and disinfect the surface. In fact, all of the active ingredients are going to be used up in cleaning the surface contamination. So, it’s only if you wipe the surface a second time that you would have any chance of disinfecting it.



How should you approach this, given the above?


1, Take in the above and implement the points raised


So, you need to not just rely on your cleaning contractor or your chemical supplier or whoever it may be to say “we’ll deal with this”, without putting some rigour into the processes that they are actually following. After all:


It’s your name over the door.


It’s your brand that could be ruined if your buildings aren’t clean or if an outbreak happens.


It’s your responsibility, ultimately, to provide a safe environment for your staff and clients. Nowadays, safe includes clean.



2, Introduce some quantification of these processes


You need to ensure that they are effective, otherwise you could easily not only waste thousands of pounds but also leave your building’s users at risk and your company at risk. Again, every man and his dog are offering COVID-19 services – I’ve even seen companies who normally do gardening! It’s your building, it’s your risk, you need to be certain that you are getting what you are paying for,


3, Remember that you need to be truly clean to be able to eradicate, and then keep away, viruses and bacteria


Even if you can’t perceive it, it is incredibly likely that you do have contamination on your floors and walls and certain other surfaces that are heavily used. This will particularly be the case in areas of buildings that have challenging contaminants such as showers, toilets, kitchens and any heavily trafficked floors.


You’ve got to get these surfaces clean first to give yourself any chance of suppressing the virus or other bacteria.


“A critical component of disinfection is prior cleaning. Prior cleaning is necessary to remove proteinaceous material and biofilms to allow the germicide to achieve adequate microbial inactivation. The use of a product that provides excellent cleaning capabilities is paramount in ensuring effective disinfection.” (The Importance of Contact Times for Disinfectants, Omidbakhsh, N. CJIC 2008)



Perception is reality


If someone walks into your building after lockdown and a table top looks a bit greasy, a floor is a bit sticky, the toilets sinks have a bit of limescale around them, and they can smell some odours of any kind, their immediate reaction is going to be one of fear.


Just as if you go to a restaurant and the washroom is a bit dirty, you wonder what does that mean about the cleanliness of the kitchen? If anyone sees any signs of contamination of any kind, in your building after lockdown, they’re going to be fearful about their safety, and they’re not going to be keen to return.



Do it right, but then communicate it to your staff and clients


And here we turn back to communication.


People are going to be paranoid about even fearful about going back to work, going to a pub. Going to a shopping centre or visiting a gym, your brand and your reputation. I’m sure are very important to you. In fact, a on the leading insurance broker published its top risk categories for corporates around the world, and reputation was number two. You have a good reputation from your customers, and your staff. Right now, I’m sure. But what would happen if on the first day, he reopened someone walks in and. The building is a bit grumpy bag in the sink. What are these guys been doing for the last 234 months since they’ve been closed. They clearly don’t care about this they clearly don’t care about my safety and mark my perception of your brand hits an all time low.


So, track what steps you’ve taken to get your building ready for relaunch, document photos and videos of the two-stage process that you’ve followed, evidence the quantifiable tests of hygiene and slip safety you’ve undertaken, show before and after images of aesthetics, put up certificates in your reception and around the building.


Do everything you can to do this properly.


Them shout about it so all your stakeholders retain the confidence in you that you’re providing them a clean, hygienic and safe environment in which to work or play.





Remember… this isn’t akin to some tissue on the floor, which might annoy somebody. This is a life or death situation and cleanliness and hygiene now needs to be considered as one of if not your top risks, at least for the foreseeable future.


Remember… the public is now acutely aware of how important cleanliness is. And so it’s down to you as a building operator to meet these newfound expectations but also to communicate them seriously to staff and your client base, so they can retain the confidence in you, and the environment that you’re providing them.


Remember… this is a devastating disease. You owe it to yourself and anyone who comes into contact with any buildings you are responsible for, to do this right.



Now’s the time to get cracking

If you have a large estate of buildings, you have no time to lose. As of this writing (2nd May 2020), most commentators expect an announcement of easing of the lockdown measures to be made within a week. Whilst most buildings will not reopen immediately, if you have lots of buildings to manage, you need to start considering what to do about this soon.



We can help you with a thorough deep clean, disinfection and testing process. Contact us to discuss.


  1. Steve Westwood on 25th June 2020 at 1:53 pm

    How often would you have
    To dry fogg a social club / pub

    • Christian Harris on 25th June 2020 at 2:33 pm

      Hi Steve,

      Thanks for the question.

      Once you’ve cleaned, you can disinfect using a spray/fogging method.

      Using standard products, as soon as that surface is contaminated (whether by human touch, dust or whatever it may be), it’s then dirty and potentially able to harbour viruses or germs.

      So, potentially, you’d need to be doing it quite frequently depending on how frequently and effectively you were doing cleaning between this, particularly of touch points.

      There are some products available that claim to have a longer-lasting effect. This could limit the need for frequent ongoing disinfection.

      You don’t necessarily need to use this method, by the way – you can achieve the same using physical cleaning & disinfection (and indeed this is what Public Health England talks about).

      Hope that helps?


  2. Fran on 29th June 2020 at 3:05 pm

    Are there products available that do the same job as electrostatic disinfection? I’m wondering if the well know household disinfection sprays that claim to kill 99.9% of bacteria are as good? Especially for soft furnishings and carpets.

    • Christian Harris on 9th July 2020 at 5:19 pm

      Hi Fram,

      You don’t need to use electrostatic sprayers at all. If you look at Public Health England they only talk about physical disinfection.

      Household sprays are probably not as effective as commercially-available products but check the data sheets.