Case study

Baffled by mezzanine floor building regulations?

Oct 14, 2021 | Mezzanine Floors

Installing a mezzanine floor is a construction activity for which Building Regulations are compulsory. The building regularity system works to protect the health, safety and wellbeing of people whist inside or near formed buildings and structures.

A mezzanine floor is fitted within the existing walls of the original building and is not classed as a permanent structure however it is a framework that can cause serious harm if not planned and constructed to the standards determined by UK Building Regulations.

UK Building Regulations cover abroad spectrum of construction works; however the following documents are applicable to mezzanine floor installations.

Approved Document A – Structure – The focus is on the integrity of the structure including the weight load bearing.

The devised weight load capacity is calculated in accordance to the activities the mezzanine level will accommodate. The reason is to prevent overloading which is why intended use is an important factor during the planning stages. A prospective change of use should also be factored in to ensure the future change can be safely accommodated.

Mezzanine floor weight load notice

Approved Document B – Fire Safety – Refers fire safety not just on the mezzanine level itself but surrounding areas also.

Users must have the ability to escape swiftly and safely in an emergency situation; therefore UK Building Regulations enforce a number of measures to ensure this. These relate to travel distances, staircase position, fire detection, alarm systems, emergency lighting and fire resistant fittings.

Approved Document K – Protection Against Falling – Outlines preventative measures against falls, collision and impact.

As an upper level platform, risk of falls and accidents to users must be eliminated by ensuring adequate edge protection and risk-free stairways.

Approved Document M – Access and use – Covers practicality in terms of use and access.

For the mezzanine to be safe and practical UK Building Regulations set specific standards to ensure such things as safe stairways, suitable flooring or easy access for the disabled like a passenger lift where appropriate.

This retail mezzanine features a Y shaped staircase

The process of obtaining approval from UK Building Regulations

The process of gaining approval under UK Building Regulations for your mezzanine floor project should start at the planning stage otherwise you run the risk of being ordered to take down the partially or fully completed structure and a hefty fine.

The following documents should be submitted to regulating officers at the proposal stage of your project:

  • Application for mezzanine floor
  • Floor layout plans of every level including the ground floor below
  • Internal building plan with mezzanine floor location highlighted
  • Building location plan
  • Structural framework calculations
  • Slab capacity calculations

Using the documents, regulating officers will need to ensure the following is incorporated into your plan:

Emergency Lighting

Poor visibility, especially in an emergency increases risk to safety, therefore it’s a requirement for mezzanine floors to be fitted with emergency lighting. If however the mezzanine floor is storage only, particularly small and is being installed in an area that already has emergency lighting, this may be efficient enough not to require additional emergency lighting.

Fire detection and alarms

Storage mezzanine floors measuring less than 10m in any direction don’t require fire detection whilst a storage mezzanine floor measuring between 10m and 20m in any direction will require either fire detection or fire resistance. A storage mezzanine floor beyond these measurements will require fire detection and an alarm system, as would a retail or office mezzanine floor, whatever their size.

Fire resistance

Any mezzanine floor accessed by the general public be it workers, customers or visitors must be fire rated whether its a storage, office and retail mezzanine.  A storage mezzanine of 10sq m or bellow is exempt and a mezzanine between 10 and 20sq m will require fire rating if fire detection has not been applied.

Inforgraphic - Storage Mezzanine Fire Safety


Manual call points

Mezzanine floors require a manual call point on every level and should be placed at the top or each stairway, however if it’s a very small storage mezzanine floor, this may not be required.

Travel distances

Referring to the distance needed to travel should users need to leave the mezzanine floor in an emergency, the length of travel should be within the distances illustrated bellow. Travel distance requirements differ in accordance to staircase numbers and mezzanine floor use and its worth noting that the distances illustrated can be longer under certain circumstances relating to sprinklers, fire detection and ceiling height however this is assessed on an individual basis.

Infographic - Mezzanine FloorTravel distances



New sprinklers are not a requirement under UK Building Regulations, however if a sprinkler system already exists there is a requirement to extend to the mezzanine floor covering all levels.


Industrial staircases used to access storage or production mezzanine floor for example can be designed to BS5395 – Part 3 which specifies the following:

  • Step height (rises) to measure between 150mm-170mm and stair tread (going) to measure between 250mm-400mm
  • Minimum clear width of steps to be 800mm
  • Risers don’t need to be closed
  • Landing space required every 16 risers
  • Contrasting required on nosings


General staircases are used for daily access whether it’s for customers using a retail mezzanine floor or staff accessing the office mezzanine. Requirements for general staircases include:

  • Step height (rises) to measure between 150mm-170mm and stair tread (going) to measure between 250mm-400mm
  • Risers to be closed
  • Landing space required every 12 risers
  • Contrast required on nosings
  • Handrail height to be 0.9m – 1.1m
  • Space between handrails 1m wide
  • 1m high guarding required

Retail mezzanine bespoke stiarcase

Utility staircases are not accessed on a daily basis. These could be fire escape stairs or back of house stairs that are only occasionally used. Requirements for utility staircases include:

  • Step height (rises) to measure between 150mm-190mm and stair tread (going) to measure between 250mm-400mm
  • Risers to be closed
  • Landing space required every 16 risers
  • Contrast required on nosings
  • Handrail height to be 0.9m – 1.1m
  • 1m high guarding required

Approval on completion

Its not just the plans that Building Control Officers need to assess and approve; checks must be made to ensure the approved plans are in place after the construction is complete.  This involves an on site visit by the officer who will inspect the structure to ensure it was implemented in accordance to the previously approved plans.

For emergency lighting, fire detection, alarms, heating, air conditioning etc, evidence by way of certification much be shown.

Once the officer is satisfied, signed documentation is handed over to you stating that the structure is in line with UK Building Regulations.

A fire rated retail mezzanine floor


Get UK Building Regulation Approval the Hassle-free Way

Obtaining approval from UK Building Regulation entails the sourcing of a reputable building control officer for whom you must fill out associated project forms and gather project documentation. You must also make arrangements for the on site visit before the project can be signed off as complete.

There is good news however, if you don’t want the hassle of obtaining approval of UK Building Regulations yourself. WSL is highly proficient in our understanding of UK Building Regulations having been in the industry for over thirty years and as a mezzanine floor designer and manufacturer accredited to the highest standards of safety and quality you can be sure of a mezzanine floor solution that meets the regulations. What’s more, our established working relationship with highly accredited and efficient building control officers mean we can make all arrangements for approval on your behalf as part of our service.  This means no forms for you to fill out, no concern about things you may not properly understand and no need to take time to make arrangements. All of this can be taken care of by our team and the only interaction between yourself and the officer will be when the final paperwork is handed over to you on completion.

Want to know more? Contact the WSL team today on 0113 2045350 or email


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