The Real Reason Trusses Are Built from Wood

Availability

Wood is readily available and is typically locally sourced throughout most of the country, especially in the northwest. Wood is also a much more sustainable building material as compared to alternatives. Often the lumber used for construction has been farmed specifically for the use in construction and building. Steel for example is typically not locally sourced, making the cost to acquire and transport the materials higher, more labor intensive, and slowing down the manufacturing process entirely.

Ease of use

Lumber is, when compared to steel, much easier to work with because of its rigid, yet malleable, make-up. Tools like saws, nails, and connector plates do not require advanced technical prowess and certification as it might for welding or other methods used when handling materials like steel.

Examples of when alternatives might be favorable

Despite lumber’s many advantages, there are scenarios in which steel for example becomes a better alternative. Long span structures that span in excess of 80 feet are an example of when switching to steel would be favorable in comparison to using lumber.

Fire safety

Resistance to fire and similar hazards carries significant differences between lumber and steel. Wood framing, in most cases, can resist structural collapse for the duration that it takes for occupants to evacuate to a safe place. In many cases wood trusses, because of their way they are engineered, can allow enough time for first responders to safely handle the fire. Steel on the other hand has a much higher tolerance for excessive heat. However, once steel reaches a certain threshold, it does result in nearly instant catastrophic failure. Nevertheless, it is important to mention that there are many methods that help lumber have higher resistance to fire such as applying fire-retardant sprays or using special paints that react to fire in a manner that create an insulating layer.