//Are Timber Frames a Fire Risk?

Timber frames are becoming increasingly popular within the construction industry, particularly for low and medium rise housing, due to their natural qualities that contribute to sustainable development. With rising popularity though, comes increased questions and concerns, specifically regarding timber frame construction fire safety.

Are timber frames a fire risk and what fire safety measures are being put into place to continue using timber frames for building developments? Let’s explore.

//What Are the Fire Risks of Timber Frame Construction?

First of all, timber is more fire resistant than you may first think. When timber is exposed to fire, the surface layer of the wood begins to char and acts as a protective barrier that insulates the inner wood and slows down the combustion process.

That said, there are fire risks to all forms of construction, including timber frame and masonry construction materials. Furthermore, although steel and concrete are often perceived as fire-resistant, high temperatures can affect their structural integrity and strength. With high structural strength and a slow charring rate, timber’s behaviour in a fire situation is fairly predictable which works to an advantage.

Notwithstanding this, in 2019, the Structural Timber Association (STA) conducted an extensive program of fire testing and tested standard timber frame build-ups to confirm fire resistance to suit 30 and 60 minute resistance. This time period was chosen to reflect the Building Regulations, which require structures to remain safe for enough time for inhabitants to safely exit the building. All of this information is recorded in Fire Research Volume One; it details the different timber frame build-ups and systems that were tested, how they were constructed and the results.

//How Do You Protect Timber Structures From Fire?

For timber structures, the use of plasterboard is essential for fire safety. Plasterboard lining provide up to 1-hour fire resistance rating for overall construction and timber frame walls.

In order to provide adequate fire resistance, there are strict requirements that must be followed. The plasterboard must be of the correct type, thickness and fixing method. The common types of plasterboard used are 15mm wallboard, which is mounted vertically, and 19mm plank type which is mounted horizontally.

Each layer should be fixed independently to support around the edges entirely by timber and joints between the layers must be staggered. It is important to note that there are specific requirements for party wall and roof junctions, as well as cavities and roof junctions, to protect timber structures from fire using plasterboard.

//Timber Frame Construction Fire Safety Regulations and Resources

The idea that timber frames are a fundamental fire risk is a misconception. The key lies in responsible construction detailing, practices, adherence to regulations and proactive maintenance.

In addition to the fire testing program, the STA also introduced a program called The STA 16 Steps to Fire Safety. This 16-step rule is now included in contractual obligations to ensure fire safety during timber frame construction, alongside the Building Regulations for fire safety requirements, as a minimum standard.

The fire safety website: Fire Safety. Wood in Construction. has been developed by Swedish Wood, Timber Development UK (TDUK) and the Structural Timber Association (STA) to provide full access to information and guidance regarding timber frame construction fire safety. This website is free to use and will be kept up to date to reflect any regulation or industry guidance changes.