Mezzanine stairs: what do the rules require?

Why the staircase matters more than it looks

The staircase is how everyone reaches the mezzanine every day and how they leave it in a fire. Its position decides travel distances, its size decides how many people can use the floor, and its footprint takes space from the ground floor. It is also one of the bigger single items on a quote. Getting it right early saves redesigns later.

Utility stairs or general access stairs?

Approved Document K, the building regulations guidance on stairs and guarding, recognises two main kinds of stair for buildings like these:

For both, twice the rise plus the going should come to between 550 and 700 mm, which keeps the steps comfortable to walk.

Most storage, warehouse and factory mezzanines use steel utility stairs. Retail floors, gyms, showrooms and other floors open to customers need general access stairs, which are shallower and so take more floor space.

For industrial buildings, Approved Document K also points to BS 5395-3, the code of practice for industrial type stairs, permanent ladders and walkways.

Working out the number of steps

Take the height from the ground floor to the top of the deck and divide by the rise. A deck at 2.8 metres needs at least 15 risers at about 187 mm each for a utility stair, which fits one flight of 16. The same height as a general access stair at 170 mm needs at least 17 risers, so it must be split into two flights with a landing. That is why public stairs often turn a corner.

Handrails, guarding and headroom

Approved Document K sets out:

• Handrails with the top 900 to 1000 mm above the pitch line of the stair.
• Guarding of at least 900 mm on stairs and 1100 mm at landings and the edges of floors in factories and warehouses.
• Headroom of at least 2 metres over escape routes.

Peninsula’s guide to mezzanine rules adds the practical details installers work to for edge protection: a main guard rail at 1100 mm, an intermediate rail leaving no gap over 470 mm, and a toe board at least 150 mm high to stop items being kicked off the edge.

Can you use a ladder instead?

Rarely. Approved Document B says fixed ladders should not be a means of escape for members of the public, and Approved Document K limits ladders and very steep stairs to occasional access, such as to plant. A floor used every day, or by more than a few people, needs a staircase. A small, rarely visited plant deck is the main exception, and building control will want to agree it.

How many staircases does a mezzanine need?

It depends on the escape distances in Approved Document B, Table 2.1. From the furthest point on the floor to a staircase, the limits are:

• Offices and shops: 18 metres if there is only one direction of escape, 45 metres if there are alternatives.
• Normal hazard industrial and storage: 25 metres one way, 45 metres with alternatives.
• Higher hazard industrial and storage: 12 metres one way, 25 metres with alternatives.

A narrow floor along one wall can often be served by one stair. A large, deep floor usually needs two, at opposite ends, so that anyone can turn away from a fire. Our mezzanine floor design page explains how stair positions are planned.

Where to put the stair

• Near the natural route people walk, but out of forklift aisles.
• Where it lands on a clear escape route on the ground floor.
• Away from the pallet gate, so people and loads do not meet.
• Where the space under it can still be used, or is protected from storage if the fire strategy requires it.

What mezzanine stairs cost

The Mezzanine Company puts a typical industrial staircase at £2,000 to £5,000, with £3,200 in its worked example. MyBuilder’s guide gives a wider £1,500 to £6,000 for staircase installation. Wider stairs, intermediate landings, general access geometry and fire-protected enclosures all push the price up.

These figures come from the sources listed below, read 26 October 2026. They exclude VAT and are a guide, not a quote. Our mezzanine floor cost calculator lets you add a second staircase and see the effect on the total.

Questions to ask the installer

1. Is the stair a utility or general access stair, and why?
2. What are the rise, going and number of risers?
3. How wide is it, and does that suit the number of people on the floor?
4. What are the handrail and guarding heights?
5. Does the escape distance work with one staircase, or is a second needed?

A good installer will show the stair on the drawings with these figures. When you are ready, our free service can find a mezzanine floor installer who covers your area.