Exposed basement stairs form a gravity-driven access that allows the rain to pool at the bottom. With nowhere else to go, the rain can enter your basement through cracks around the foundation or the basement door. Diverting the rain or erecting a barrier over the steps can help protect your basement from the incoming water that ruins your possessions and creates a hospitable environment for mold to grow.
Divert The Water
Without a guttering system around a roof's perimeter to catch the rainfall and divert it through downspouts to the ground, rain falls in sheets off the roof. Whatever lies directly beneath the roof's drip line, such as basement steps, collects the water. Design a guttering system to move water away from the basement steps, but make sure the downspouts do not flank the stairs. Otherwise, water may pour out of the downspouts and into the stairwell.
Extend The Roof
An extension of your roof that covers the steps prevents rain water from rushing toward the basement door. You can enlarge the actual roof over the section of stairs, which adds visual continuity to the structure of your house because of the matching shingles. Alternatively, erecting an awning over the basement steps provides a suitable rain barrier. Fabric, metal and fiberglass are awning material options to suit individual budgets and preferences. Awning shapes vary -- including downward-slanted to "eyebrow-shaped."
Shut The Door
Basement walkout doors conjure images of storm cellars. Unlike with storm cellars, however, doors over basement steps typically abut your home instead of covering detached structures. Basement doors may be single or double, and they may be made of wood or metal. The doors not only protect basement steps from rain water, but they also provide a safety feature by preventing people and pets from tumbling down the uncovered stairs. The key to their effectiveness is making sure they are watertight by installing them properly.
Finish The Job
After an overhead structure is in place -- whether it's a guttering system or a rain barrier -- the job's not yet finished. Downspouts typically empty onto splash blocks, which are not efficient in removing rain water away from a home's foundation and basement stairs. Covering the downspout terminals with 5- to 10-foot extenders moves water a safer distance away. If the ground is not properly graded, diverted rain water may back up against your house and flood the basement steps. The recommended grade is a minimum 6-inch fall over a 10-foot distance away from your home's foundation. If you install basement doors, caulk with a silicone sealant on the contact points where the foundation meets the door frame.