Safety considerations for timber frame structures

By | 2019-09-04T13:14:23+00:00 September 4th, 2019|

Timber-frame construction is one of the oldest known building methods, especially in the northern hemisphere, largely due to the sturdy and resilient qualities of timber, and the relative ease of construction.

There are important safety considerations to take into account with regards to timber frame construction. Image credit: Pixabay

There are important safety considerations to take into account with regards to timber frame construction. Image credit: Pixabay

There are important safety aspects that need to be considered with timber frame construction.

Extreme weather conditions

Thanks to modern timber treatments such as anti-fungal and beetle treatments, timber homes can last indefinitely. Structural timber is treated against termite infestation and fungal attack. Timber frame structures in wet and damp conditions are at greater risk for the wood to rot than in dry climates. If maintenance schedules are adhered to (or even shortened) and not skipped, it will obviously mitigate these risks and it will continue to protect the wood against rot and disease.

Fire

Timber is combustible but not flammable, which means it needs a high temperature to get it burning. Large dimension timber is advantageous during a fire, as it chars on the outside, while retaining its strength, slowing combustion and prolonging time for evacuation or fire control. Timber also has a significantly lower heat conductivity than steel or concrete. Fire engineers can calculate burn and charring rates, and hence the safety factor for varying sizes of timber. Timber is also treated with fire-retardant materials and firewalls are also incorporated, slowing down the burning rate making these structures safer.

Seismic activity

The most earthquake-resistant structures are typically a low wooden structure, which is anchored to its foundation and sheathed with thick plywood. Traditional building methods in Japan, a high-risk seismic activity country, incorporates shock-resistant design of timber construction into buildings, some of which are over a thousand years old. Traditionally, different cultures in high-earthquake risk countries have used unreinforced masonry and shock-resistant timber structures. Timber frame construction is undoubtedly the safest and most durable form of construction for specifically earthquake conditions.

The structures are lightweight and withstand the horizontal forces imposed during an earthquake as it has lateral bracing built in as part of its design. Timber can flex and return to its original shape, unlike its concrete and masonry counterparts. Joints are also typically the fail zones in traditional structures, as the reinforcing and/or joints will loosen during an earthquake, causing building failure and potential collapse. However, this failure and collapse are rare for timber constructions if correctly engineered and constructed.

Strong winds

High-speed and high-force winds can cause damage to buildings, depending on the buildings particular characteristics including strength, stiffness and shape, each of which alter a building’s reaction to wind loading. Timber is light-weight and flexible, making it ideal for high wind-load environments, and allowing timber structures to withstand substantially greater maximum loads for short durations. Timber construction, with repetitive members and multiple connections, create redundant load paths to effectively transfer wind forces down to the foundations below.