Which of the following activities can contribute to structural ignitability?

The activity that can contribute to structural ignitability is the use of wooden roofs and decks without proper treatment. This choice highlights the vulnerability of untreated wooden structures to fire. Wood, especially if untreated, can easily ignite from embers, direct flames, or heat exposure during a wildfire event. Without protective treatments, the wooden materials do not possess enhanced resistance to fire, increasing the risk of ignition, which can lead to significant structural damage or total loss.

In contrast, the use of non-flammable building materials and fire-resistant glass windows significantly improves the fire resistance of a structure, reducing the likelihood of ignitability. Keeping the area around the home free from debris is also an important mitigation strategy, as it minimizes fuel sources that could contribute to the spread of fire to the structure. These activities are focused on reducing risks and enhancing the protection of buildings against wildfires.