How to specify timber stairs

[edit] Specifications

Timber stairs play a pivotal role in the design and functionality of new homes, offering both aesthetic appeal and structural integrity. But what is the sector doing to make it easier to specify these elements?

There have been more legislative changes recently in the housing sector than at any other time, presenting a challenge for specifiers. Having to keep up to date with them can be time consuming and laborious. Suppliers can help by making sure that compliance issues created by the updates are picked up at the design stage and then offered to designers as fully workable, compliant solutions. Key to making this work is bringing together groups of manufacturers with specific expertise in all their associated products. For example, when it comes to stairs, it might involve creating a system-based solution with floors, joist and partitioning suppliers – and then sharing these solutions via easy access platforms, either

BIM or the new Whole House programme. That gives specifiers the confidence that what they specify has been thought through from day one, with input from all relevant parties. Specifying any type of stairs requires understanding of various factors, including design standards, materials, load requirements and regulatory compliance. Timber stairs are more than functional elements; they are integral to the overall design and feel of a building. Their selection, as with all types of stair materials, needs to take into account the following factors:

[edit] Building Regulations

When specifying stairs, it is important to adhere to established design standards. The British Standards Institution (BSI) and the Building Regulations provide guidelines that ensure safety and performance. BS 5395-1 outlines the code of practice for the design of stairs with straight flights and winders constructed of wood-based materials.

Approved Document K includes dimensions, safety features, load-bearing capacities and fire safety regulations. Dimensions are perhaps the most fundamental aspect outlined in Approved Document K. The rise and run of each step must be carefully calculated to prevent accidents. For instance, the maximum rise of a step is typically set at 220mm, while the minimum going (the depth of the tread) is generally 220mm as well. These measurements are designed to accommodate a wide range of users, including those with mobility requirements.

Safety features are another critical component of Approved Document K. Handrails, for instance, are not merely decorative; they are essential for providing support and stability. The document specifies that handrails must be installed at a height between 900mm and 1000mm above the pitch line of the stairs.

Furthermore, load-bearing capacities are addressed in the document to ensure that staircases can withstand not only the weight of users but also any potential loads from furniture, equipment, or other objects that may be moved up and down.

All stairs must also comply with fire safety regulations, particularly in multi-storey buildings. Timber stairs are often supplied with fire-resistant coatings or treatments, which enhance fire resistance, ensuring compliance with regulations, while providing peace of mind for occupants.

[edit] Certification and Standards

Working with certified manufacturers and suppliers ensures that the timber stairs meet the necessary standards. The British Woodworking Federation (BWF) Stair Scheme provides accreditation for quality manufacturers, ensuring compliance with industry standards.

[edit] Whole House

Advancements in technology, particularly Building Information Modelling (BIM), have revolutionised the way timber stairs are specified and designed. The Travis Perkins Whole House platform utilises our Revit models to create digital twins of stair designs, allowing for enhanced visualisation and planning. We also use Revit output for joists and decking as well as Revit to produce BIM models for skirting, architrave and door kits.

Whole House makes it much easier for specifiers to create sustainable building designs, quicker and without wasting valuable resources. The platform, which was developed by a group of over 20 manufacturers, now allows designers to plan, design, and configure an entire home in a matter of hours. It brings together all these separate manufacturer components as verified and workable designs.

With a choice of 2, 3 or 4 bed house types to choose from, specifiers will have confidence that the stairs and all other elements are fully compatible and within building regulations as the manufacturers have already done all the work behind the scenes. Being able to review the design in 3D eliminates any issues, whilst allowing specifiers to try different options to test spatial layouts.

We provide a range of BIM models that can be integrated into the design process. These models include detailed specifications for various timber stair designs. Digital models reduce the likelihood of errors in measurements and specifications, leading to a more efficient construction process.

When specifying timber stairs, either via Whole House or by working directly with the supplier’s models, it is important to verify that they are PEFC and FSC certified, which means they support environmentally conscious practices that help preserve our planet. We have taken this a step further by making our floor and stair products carbon negative, which means that not only do these products have a reduced carbon footprint during their lifecycle, but they also actively contribute to reducing carbon dioxide levels in the atmosphere. That means they are helping to combat climate change right from the moment they are installed. Our products maintain their carbon-negative status up to and including installation. This ensures that every step of the process, from manufacturing to fitting, aligns with eco-friendly practices.

Specifying timber stairs involves a multifaceted approach that considers design standards, material selection, load requirements, and compliance with regulations. To make this easier, BIM, and more recently platforms such as Whole House, help specifiers stay up to date with latest legislation, while providing compliant, workable solutions to specifiers.

By leveraging technology, specifiers can ensure that their stairs are not only aesthetically pleasing but are also safe and functional. Ultimately, a well-specified timber stair design contributes to the overall success of a housing project, enhancing both its value and liveability.

This article appears in the AT Journal issue 154 summer 2025. as "How to specify timber stairs" Neil Wycherley, Head of Technical, Staircraft.

--CIAT

[edit] Related articles on Designing Buildings

• Accommodation stair.
• Approved Document B.
• Approved Document K.
• Approved Document M.
• Alternating tread stairs.
• Banister.
• Flight.
• Guarding.
• Hellerup stairs.
• Landings in buildings.
• Maximum length of a flight of stairs.
• Means of escape.
• Protected stairway.
• Protected stair v escape stair.
• Railings.
• Spiral stairs and helical stairs.
• Stair design.
• Stairs going.
• Stairs nosing.
• Stairs riser.
• Stairs string.
• Stairs tread.
• Types of stairs.
• Width of doors stairs and escape routes.
• Winder.