Mezzanine construction – 9 things you need to know
A mezzanine is a good investment. A mezzanine is a very easy way to create additional, very cheap productive space. Building your mezzanine should be very easy from an engineering point of view, but there are differing opinions on the design. People with vested interests who want to deal with your project, often as part of other work they may be doing at the time, can easily convince you to embark on a course that does not meet your expectations. You should not deviate from this, there are certain fundamentals that if implemented will ensure that you do not fall into the trap of popular opinion, which is not the same as expert advice.
There are over 40 combinations and conveniences that a mezzanine can bring to your business and they can be expensive in the wrong hands, causing delays and unnecessary frustration. A mezzanine should provide a flexible, low-cost productive business space, and armed with these eight basic principles, your mezzanine structure is much more likely to maximize its contribution. My fastest payback time for a mezzanine building project was under 3 months. These are the eight useful things you need to know to get quick results for returns.
The first thing I need to know: Why would I want a mezzanine? The mezzanine makes a great space for people, so showrooms, shops, restaurants, offices, warehouses, manufacturing, workshops, exhibitions, museums, schools, libraries, high schools and leisure are good examples of work. They are easy to retro-fit and can be taken down again with relative ease, making them good for landlord, tenant and private property as an obvious choice for developing temporary or permanent space provision. Landlords often provide these facilities by incentivizing the cost of rent.
Second thing you need to know: Is there potential and how much would a mezzanine cost? Once you’re in your building, warehouse or factory unit or even a shopping center or out-of-town location, if no one has occupied it before you, then you’ll have maybe some basic hospitality and some services and a lot of floor space. Here in the UK it is common for architects and building contractors to use steel frames because they can go higher more economically. In warehouses, the structure is often a series of frames, called portal frames, to which the cladding rails and building skin are fixed. If your property is not already subdivided for you then you will be staring at rafters and in a portal frame building you should have up to 6 meters at the eaves and a meter or more of extra peak height in the middle. If you look up at the roof rafters on the side of the building from the inside, you’ll see a funny little triangular bracket between the rafters and the column – we call this a hill and it’s usually about 5m more than the underside.
Anything over 5m is good, under 5m you will need professional help. If you are building this structure, make sure you have at least 6 meters to this point and then you can install a mezzanine if you ever want one completely unrestricted from the side. There are many reasons not to build at this height, but low-level production units won’t work as warehouses later, so unless you really can afford to go higher, use the height because you’ll add value by more -broad appeal than if you were to stay low. Anyway, all that being said, why it’s free space is because you’ve bought or leased the floor space, so the head space is technically free from an ownership perspective. Mezzanines have a price spread of £90 to £250 per square metre, less than half the cost of a new build, so relatively cheap to build. Not only this, unless it is more than about half to two-thirds of the total floor area, it can be exempt from council tax, especially if it is a movable structure, as it is considered part of the plant. So read on…
Third thing you need to know: Do I need planning permission for a mezzanine? No, you don’t need planning permission unless you’re changing the look of your building with windows for example, but you do need building regulations in England and Wales and an order in Scotland, and here’s what you need to know about them:
- You need proof that the load-bearing concrete floor is structurally able to withstand the imposed loads.
- You must have a designated approved exit route from the floor and the building to comply with fire regulations.
- You need to make sure that the floor can withstand a fire for up to an hour if people are working on it.
- You need drawings of the proposed works.
- You need a block plan and a site plan.
- You must provide structural calculations demonstrating the steel structure and pavement will carry the design loads.
There are several other elements that flow from this, but these are the main ones. In England and Wales you can proceed before Building Regulations, but be warned that if changes are ordered during this statutory process, it can result in expensive re-work, which you will be charged for. In Scotland you need the warrant first and any qualified civil engineer can sign the warrant. If you are in the design phase, you will need to ensure that footings are provided for all supporting floor columns, they are lowered before the floor is poured. If you don’t have this option, you’ll need to check that the ground can take the weight without cracking your floor.
The fourth thing you need to know: How long will it take to build a mezzanine? Well, if there are no problems getting approvals, 2 to 4 weeks for small floors, 8 to 12 weeks for floors the size of a football field, and somewhere in between for the rest. Planning will take 6 weeks if you know what you’re doing, more if you don’t, and building regulations 2 to 3 weeks if you use an agent, 6 weeks if you don’t. Add design and planning time for yourself and getting prices etc. If you have a weak foundation, you may need to add 6 weeks for design and 6 weeks for earthworks, so don’t start winding up your support teams for deadlines. It takes 28 days for concrete to reach a specific hardness, no matter what pressure you are under, unless you add expensive resins, which is not always advisable. There will also be sampling and design work to allow enough time for orderly progress and a job well done. Even with all this, it will be an economical solution for you.
The fifth thing you need to know: Who should I buy it from? There are specialists. You can put in a concrete mezzanine in the design phase, they can be quieter, better for wet process or production rooms and cover larger spaces, but they usually cost a lot more. For heavy stuff or special design areas, the contractor may have a good solution. I would avoid contractors for all remodeling and go to professionals instead. I would also encourage you to thoroughly research the benefits of separating the mezzanine from the main shell, 9 times out of 10 it will serve you better. Buy them from warehousing specialists, or even better, material handling engineers, then you’ll get help with all other aspects as well.
The sixth thing you need to know: Should I buy second hand? Chipboard decking rarely comes out well when the floor is removed. There are at least three construction methods and several material specifications, all performing different tasks. Once the materials are removed from the main structure, even experts have problems with them. Hot rolled sections are designed to take specific loads with specific properties. I have yet to meet anyone who has bought a used floor who can report this information or who knows if their construction is 360, 250 or center design, what the service or dead load is, or provide any structural calculations for the floor, other than the very rare original calculations that were provided for specific cases for this application and not for the current application after apparently sitting in someone’s yard for six months.
If you move a floor, the manufacturer must re-approve the calculations and issue a certificate of inspection. You are unlikely to find a used floor in the possession of someone qualified to provide this maintenance. I have found that people actually pay more for used floors than they do for new. It costs about 25% of the cost of a new floor to have it removed and properly packed for dry storage, properly inspected and labeled. So does reinstalling it. You’ll spend another 30% to 40% with a reputable salvage company to reassemble the spec for your application, including correct structural information. Unless you are willing to do the work yourself and know the location and history of the floor and put it back the way it fell, avoid it. The only real value is scrap or architectural residue for reuse by experts.
The seventh thing you need to know: How can I know that I am being sold a new mezzanine and not a used one? Yes, I’m afraid that’s what’s happening. All you can do is get references, ask about the issues raised above and always get 3 quotes, remembering that if something sounds too good to be true, it probably is. If in doubt, you cannot hide scars and damaged materials and do not part with any money until you have all the correct technical information for the authorities.
Eighth thing to know: How do I know if my mezzanine design is correct? Often the floor will be made to suit the application, this can range from packaging materials to a nightclub. Whatever it is, if you are assisted by a material handling engineer, then plans will be drawn up illustrating the activities with specific load information to be introduced in the production phase of the project. Specifically, this will include:
- Finishing details of the decking to adjacent structures without clearances
- Floor supports and hot-rolled profiles, sympathetically and evenly spaced
- Deviation ratings rated for you for the app (don’t want to feel like a trampoline)
- Methods of supplying required goods, services and facilities to or from the floor or to and from the floor
- Declaration of full access and assurance of personal well-being on the floor
- Finished floor height and all structural technical details taken care of for you
- Finishing details for doors, carpets or special surfaces aligned to existing structures
There are many other things, all under the rubric of attention to detail.
Ninth thing you need to know: What kind of equipment should I consider to go with a mezzanine? The easiest answer is a list of equipment that usually comes with mezzanine applications:
- Stairs in steel, stainless steel and wood and steel
- Steel fire escapes
- Cat stairs
- Elevators
- Freight elevators
- Lifts for wheelchairs
- Lifting tables
- Storage systems including shelving
- Pallet loading gates
- Conveyors
- Chutes
- Lifts
- Mobile pallet stackers with electric lifts (cheaper than lifts)
- Railings
- Barriers
- Doors
- Ceilings
- Fireproof materials
A few more storage ideas These 9 guides will help you decide how you want to proceed with your new mezzanine project, but there are alternative ways to use headroom, such as raised storage platforms for bulkier items that can’t be conveniently stored in shelves or pallet racks. Two-tier systems are also an alternative, you can use pallet racks or shelving sections to build storage and flooring at the top of your building.
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