6.2 Distance from Ocean

When waves break, salt water is aerosolized, and the wind tends to distribute the salt spray to inland areas. The amount of salt spray in the air is greatest near breaking waves and declines rapidly in the first 300 to 3,000 feet landward of the shoreline. Despite the inland reduction, studies have shown accelerated corrosion rates as far inland as 5 to 10 miles (IMOA, 2009). Farther landward, corrosion can be similar to the rates that occur in milder, inland conditions.

Although the width of high-corrosion areas varies along the shoreline, it is appropriate to assume that oceanfront and nearshore buildings can be more severely affected than buildings farther inland. Tests in North Carolina in the 1940s found that samples of iron corroded 10 times faster 80 feet landward of the shoreline than samples of the same material 800 feet landward of the shoreline (LaQue, 1975). Similar results have been noted around the world.