Mezzanine Floor Regulations
Thinking about creating some extra work space?
Not sure how to go about it?
Perhaps you already have a mezzanine?
Well here is what you need to know.
The most common confusions that arise are the differences between planning permission and building regulations. The former basically deals with the ‘what’ and the latter deals with the ‘how’. The ‘why’ of it saves lives and prevents arguments and fighting. It really is that simple.
In terms of ‘when’ each set of regulations prevails, again it is fairly simple. You need permission to build or fix anything permanently to the ground. If you then want to change how it looks you again need permission as you will too if you try to change how it is used. If you start using your house as a factory or your factory as a house the local authority is going to take a very keen interest in you. However, if you already have a factory and wish to erect structures within their walls otherwise invisible to your neighbours, then the planners who said you could build your factory are not interested. The engineers will be very interested because they want to know that what you intend to construct won’t collapse, collapse anything else, won’t explode, burst into flames or fry someone because they cannot escape in an emergency. They get particularly agitated when it subsequently involves fire crews and medics sent in to recover unsuspecting employees or visitors who become entangled in an unexpected development. Fire crews and medics are expensive to train and their families already have enough to worry about without adding to the length of their working day unnecessarily.
So the engineers step in with a few how to’s and here they are:
1) Loading: Industrial mezzanine floors are designed to take either offices or commercial workspace. For offices, a visualised floor loading approximating to 4 people standing in a doorway talking to each other is one loading equating to 350 kgs per square meter. The next weight loading standard applies to a 1000mm x 1200mm UK pallet which equates to 480 kgs or 4.8 kilonewtons per square meter as we like to say in engineering terms. This is because we have to do other calculations when mass and forces cause us to do some fairly impressive mathematics. Personally, I think half a tonne is the best figure for industrial applications because it future proofs the investment to a greater extent and the price difference is minimal.
However much higher loadings are achievable and alternative building materials may help with such a requirement.
2) Existing Structures: The next big thing is making sure your supporting ground floor doesn’t give way under the weight. So before you make some regrettable decisions in this respect we have to calculate the weight applied by your mezzanine floor based upon it being fully loaded. For the smallest of floors this can easily exceed 20 tonnes and it may finish up going down only two legs (or supporting column as we refer to call them), producing a phenomenal loading on the footplate. The same effect as stiletto heels on a wood floor basically. To cap it all if you are the boss it is your problem, you will be held accountable and you will be asked to demonstrate you have made an effort to find out. So more maths I’m afraid plus a short course in geotechnical engineering and laboratory analytics to add to your MBO, sorry MBA. If you happen to have a PhD in Engineering you will already realise you are missing some qualifications, so although being an engineer will help you at least understand the process, it may not get you through it.
3) Fire: This is the best bit because it is really confusing. You must fire rate the floor if people are working up there for prolonged periods. You must provide a safe means of escape and maybe to a separate atmosphere which could require an external door. Now you do need planning consent to do that. You could enclose the stairs but that means you will have to fire rate the whole structure. If you leave it open you may not need to fire rate it but you may also require a secondary means of escape and a fireman’s pole is not acceptable because they are not designed for firemen to go up with breathing apparatus to get you out. The same applies to cat ladders. Fire rating and wiring, lighting and other services are significant.
4) Protection and responsible use: Weekend raves are out because you will need change of use permission. Some really odd things can happen if everyone starts jumping up and down on the floor when it is tightly packed when The Black Eyed Peas start up with Tonights going to be a good night! So think through how you intend to use it and your expectations and protect the installation accordingly. Most mezzanines are fitted with timber manmade decking and they don’t like getting wet. They don’t like heavy pallet trucks and a fork truck is out of the question. Remember the stiletto heal remark? Racks do the same thing!! So manage your expectations accordingly. Designs are of course available for almost any conditions you require at a price. Finally give some thought as to how you intend to get goods, people and equipment on and off the floor in safety with no surprise arrivals at ground level. There are some well tried and tested methods to help you achieve this, not everyone who makes mezzanines have all these resources available to help you arrive at perfection.
5) Access: Safety gates, stairs, lifts, conveyors, and chutes. Not hoists or cranes unless it is for a specific or regular process.
You should always obtain expert advice.
6) Used Equipment: This is how the used equipment market (should) work(s). The products are removed and stored, hopefully inside in dry conditions, but not always, following a full survey prior to dismantling. Drawings of the original floor are carefully prepared and all the components are labelled and numbered so they go back together exactly the way they were originally assembled, packed and protected, Why? Because that is how the structural calculations were prepared and they only apply to those components in that location. Not surprisingly this actually is not cheaper than a new floor because all that is saved are the materials which are cheaper than the manufacturing labour required to make them. Doing it this way only saves money if you use your own labour and dispense entirely with the procedures just described. In 50 years I have never seen a compliant re-housed mezzanine complete with required documentation. It is an unregulated market place and you really need to know what you are doing to achieve a safe, DIY, compliant, cheaper result. You still have to submit the documents to the local authority proving you have complied with building regulations and the other 5 points eluded to above.
7) Tax and other Regulatory Implications: Mezzanine floors along with parking spaces are rateable, so if your floor results in more traffic issues the planners are going to take a keen interest in that especially if you start clogging up main routes because of waiting lorries. The drivers may have some choice words for you as well. Remember the importance of set down space maneuvering and floor loading times. Drivers don’t have time to wait whilst your fork truck operator organises your stock. You may well finish up back in the hands of the planners if this occurs. Additionally size matters. Once your floor becomes a significant proportion of your existing floor space charges may be levied and assessment carried out. Failure to disclose this can cause trouble at a future date.
8) Installation – What to expect: If you haven’t given up on the idea altogether and still want more information, remember it has to be installed. Floors can be installed by hand, it is not always practical, it is slow and requires experienced crews. The more common way is to use MEWPs/hydraulic scissor lifts and a fork truck. Genie lifts and trolleys are an alternative, just not a quick one. As a rough guide somewhere between 40 and 55 square meters can be erected per day with a two-man team, (but don’t tell them that!) {Our} teams are truly amazing and will arrive with an armoury of tools and skills and nothing upsets them…..except not being able to unload the lorry, nowhere to put anything and gear turning up late. Apart from that they usually get on with it.
When they arrive on site they will be expected to be shown where the hospitality facilities are, where they can park, where the keys to the hire gear are and where the nearest sandwich shop is.
Erecting steelwork is very noisy, ear defense is mandatory and they won’t want your staff milling about getting in the way. To avoid this you will be given a method statement and they will have a chat with your staff at the start of each day. They call this “toolbox” and makes sure conflicts of interest are avoided. The easy way is to unload to a location next to the install, room permitting. However, this is not always practical and we need some space at least equivalent to the size of the truck that delivered it so that it can be set out. Erecting over existing machinery and installations is fraught, but can be done but it is not encouraged and some companies may refuse to do it at all, the method statement and risk assessment requirements are encyclopedic.
9) Estimates and Surveys: All in all a good preliminary survey before any metal is cut makes a huge difference as to how your project works out. To start the process use WhatsApp and relay the location to a surveyor. It will be enough to assemble a loose budget for feasibility purposes and a lot can be sorted out in these early stages this way. If this doesn’t financially shock you a detailed survey with design and equipment and setting out supporting systems can be devised and quoted for. At this point, the delete button is still a free option.
Once a decision is made, further surveys already quoted can be carried out with manufacturing and permissions all lined up with a high degree of confidence.
10) what you need to know about designs: To go back to our `Black Eyed Peas analogy, tonight will not be a good night, for long if your floor starts to perform like a trampoline. We define this by the amount your floor deflects under load when that load is uniformly evenly distributed over the whole floor. It is normal to have a safety factor of about 4 or so in such designs. However static loads and dynamic loads are measured in different ways because they apply different forces. The distance between supporting columns is also a factor as are the materials used. You should understand this because it really makes a difference. Normally a distance of between 250 mm and 300 mm is used to gauge how the deflection is measured. For example 4mm over 250mm is much greater than the same 4mm over 360 mm. The implication on cost however is significant and it can be used to reduce prices and win business.
11) How can I tell if my floor is behaving safely: Simple, unload it and the structural sections should return level (if it has been installed level). If they remain bowed, then it has been overloaded and stressed. That is why you should display load safety notices.
12) Inspections: You should inspect your mezzanine floor at least once a year and every time there is an incident. As a bare minimum check the boarding, that the underside fixings are all tight, and the floor fixings are all in position with no damage to the columns. Specifically, if your floor is ‘bouncy’ this will act on all the fixings and the movement can loosen them as can excessive temperature variations which is why they have to be checked periodically. It is best done by experienced teams.
Just remember this… You get what you pay for.
This covers the main aspects, but our advice is to ask an expert or specialist on these structures and especially materials handling systems.
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