Few homeowners realize that their decks require proper flashing in order to keep them safe and meet strict code requirements to pass inspections. Without deck flashing, a deck’s life span decreases significantly, as it becomes more prone to breaking down.

The deck flashing fits over a ledge beam to create a barrier between the deck and the house. Although it is not that easy to see at a glance, the deck flashing proves to be important to the deck’s construction.

Deck flashing protects homes against water damage. For instance, a deck without flashing allows rainwater to seep between the deck and the house. This causes damage to both the home and the deck. Over time, moisture will build up on the deck’s wood, particularly in the spot where the flashing should be, and mold and fungi could start to grow in the wet areas. According to the North American Deck and Railing Association, mold and fungi typically cause wood to rot. If that builds up enough over time, the deck’s wooden construction could weaken and cause the deck to pull away from the home or lead to catastrophic deck failure.

Fortunately, a deck without proper flashing can be easily fixed if the damage isn’t too bad. Materials for the deck flashing include copper, stainless steel or vinyl. There is also aluminum or galvanized steel flashing; however, those are less recommended for use because they are prone to corrosion. In addition, vinyl should only be used in regions of the United States with fewer extreme temperature fluctuations. Finally, it’s recommended homeowners seek professional help to add deck flashing to an existing deck.