Fire safety regulations for timber staircases

Fire safety should naturally be at the forefront of your mind with any new building or renovation project.

As with all standards, fire safety regulations for timber staircases are particularly stringent and can seem very complicated and confusing.

We have therefore put together a handy guide which should prove useful when undertaking a project involving stairs.

What are the current regulations?

Part B of Building Regulations for England and Wales outline a number of precautions that you need to take which aim to protect life by:

— Providing escape routes from the home — Restricting or preventing the spread of fire to or from neighbouring homes — Restricting or preventing the spread of fire inside the home — Providing essential access for the fire brigade

For all homes where the first floor is no higher than 4.5m above the exterior ground level, escape routes need to be accessible from all habitable rooms (i.e. bedrooms, not bathrooms). However, things are a little different for homes three or more storeys high.

Providing the top floor doesn’t exceed 7.5m high, three or four storey homes must have a protected stairway that is continuous to an external door or provides access to at least two escape routes at ground level. As the stairway is the only means of escape from the upper floors, it must be constructed of material that is fire resistant for at least 30 minutes and all habitable rooms along it are required to have FD20-rated fire doors.

Any homes with top floors above 7.5m will need to include a second escape staircase or added protection, such as sprinklers, to compensate.

What about loft conversions?

A typical loft conversion to a two storey house will be subject to much of the same regulation as outlined above. In addition, a protected route must be provided via a stairway that does not pass through any rooms. As well as this, existing first floor ceilings will need to be adapted to achieve 30 minutes of fire resistance and mains powered, interlinked smoke alarms should be fitted.

How can I make my staircase safer?

As well as meeting structural regulations and recommendations for your timber staircase, there are extra steps to take to improve its fire resistance. BS 476-7 relates to the surface spread of flame and defines four Classes in decreasing order of performance. Most untreated timber will be Class 3, but for surfaces in escape routes, such as staircases, the material will need to meet Class 0 on solid wood and Class 1 on plywood.

Here at Multi-Turn, we use HR Prof – an eco-friendly fire retardant that meets the classifications of Class 0 (Euro Class B). The product is water-based and will absorb into the cell structure of the timber without forming a surface finish, allowing the wood to breathe naturally. During a fire when temperatures of up to 1700°C are reached, materials exposed to the fire that have been treated with HR Prof will form a carbon char on the immediate area, restricting the spread of flame.

You can see the effects in a sample fire test we carried out:

If you’d like to find out more about the retardant used on our timber staircases, get in touch with us on 01962 712299 or

Disclaimer: This is our own interpretation of the general guidelines and you should obtain independent expert advice for your particular project.