Lawn sprinkler systems that keep the deck wet regularly contribute to what?

Lawn sprinkler systems that consistently keep the deck wet can lead to decay primarily due to the increased moisture exposure to wooden or composite materials. This consistent dampness creates an environment conducive to the growth of mold and mildew, which can eventually break down the structural components of the deck. Over time, the wood can absorb excessive moisture, leading to rot and decay, compromising the integrity and safety of the deck.

In contrast, the other options, while they may seem relevant, do not accurately reflect the issue at hand. Structural integrity refers to maintaining strength and support, which is undermined by moisture-related decay. Water preservation suggests efficient use of water, which is not a benefit of a system that creates constant wet conditions. Soil erosion implies that soil is being washed away, but the focus in this case is more on the structural decay of the deck material rather than the soil itself. Therefore, the primary concern with wet decks due to sprinkler systems is the potential for decay.