Traditionally, deck stairs land directly on a patio made of concrete, stone, or a material other than soil to prevent rot and decay. These landings can shift freely with frost movement. Frost movement is the rise and fall of the soil due to underground water freezing and expanding. Recently there have been some concerns regarding frost movement and the stair’s ability to withstand the fluctuations. Typically, stairs have more freedom of movement than the deck, but some builders argue the stairs should be supported just like the deck. This topic is a grey area because it all depends on each deck’s situation.