Does a mezzanine floor need building regulations approval?

Normally yes. A mezzanine creates a new floor level inside an existing building, which engages structure, fire protection, means of escape and often services and accessibility. The route to approval is set out on gov.uk, and the position for your specific building should be confirmed with a building control body before ordering.

Do I need planning permission for a mezzanine floor?

Sometimes. Building regulations and planning permission are separate systems, and adding floorspace can engage planning depending on the building's use and how much floorspace is created, which matters particularly for retail. Check with your local planning authority for your specific case rather than relying on a general rule.

Who applies for approval, me or the mezzanine installer?

It depends entirely on the contract. Some installers include a full compliance package with drawings, calculations, the application and inspections; others quote the steel and leave approval to you. Ask the question in writing, because it is one of the most common differences between two quotes for the same floor.

Guide

Mezzanine floors and building regulations: what approval involves

Updated 2026-08-14

Steel arriving on a lorry is not the start of a mezzanine project. Approval is, and it is the part that decides how much steel you need.

Why approval is normally required

Adding a mezzanine creates a new floor level inside an existing building. That engages the structure of the building, the fire protection of that structure, the means of escape for people using it, and often accessibility, ventilation and electrical work. Building regulations approval is therefore the normal position for a mezzanine, and the route to it is set out on gov.uk (building regulations approval). Confirm the position for your specific building with a building control body before you order anything.

What gets assessed

Structure: the mezzanine itself, and the effect of concentrated column loads on the existing slab and frame.
Fire safety: fire resistance of the structure, protection of escape routes, travel distances, alarm and emergency lighting. See fire protection.
Access: staircases, handrails, guarding, and accessibility provisions depending on the use of the new floor.
Services: electrical work, and alterations to sprinklers, detection, heating or ventilation caused by the new deck.
Energy and ventilation, where an office or occupied space is being created.

The Approved Documents are the reference

The technical guidance sits in the Approved Documents, published on gov.uk (the Approved Documents collection), with fire safety in Approved Document B (Approved Document B). How a raised floor level is treated depends on its size relative to the space below, its use and the building as a whole, so the outcome for your mezzanine has to be confirmed by a building control body or a fire engineer looking at your building. Treat anything a supplier tells you about thresholds as something to verify, not as a specification.

Planning permission can also be engaged

Building regulations and planning permission are separate systems and you may need both. Adding floorspace can bring planning into play depending on the use of the building and how much floorspace is created, which is particularly relevant for retail. Check the current position for your case before you commit (gov.uk planning permission), and ask your local planning authority if there is any doubt. Listed buildings and buildings in conservation areas have their own consents.

Practical sequence

Fix the intended use and the loading before anything else, because everything downstream follows from it.
Get the fire strategy discussed early with building control or a fire engineer. It is the single biggest determinant of cost.
Have the existing slab investigated before a fixed price is agreed. See loading and the slab.
Ask each installer, in writing, whether the building regulations application, drawings, calculations and inspections are inside their price or outside it.
Keep the approval documents. They are what a future buyer, insurer or tenant will ask for, and reconstructing them later is expensive.

Once the floor is in use, fire safety in the workplace is a continuing duty under the Regulatory Reform (Fire Safety) Order 2005 (gov.uk workplace fire safety), so the fire risk assessment needs updating to reflect the new floor.