402 Landscape Design, Installation, and Management Copyright Goodheart-Willcox Co., Inc. Patios and decks are valued for their versatility and as an extension of indoor living space. In many parts of the country, these areas are used for many months of the year for entertaining, relaxation, and as a viewing platform to observe other features of the landscape and surrounding areas. Stairs Outdoor stairs are needed on raised decks and in sloped areas of the land- scape design. (Slope is the rise and fall of the land surface or a change in eleva- tion from a fi xed point. It may also be referred to as the grade of the land.) The stairs may be purely functional, such as one or two wooden steps leading down from a raised wooden deck, or an integral part of the design. For safety and ease of use, outdoor stairs should be constructed at the same standard height (7″) and width (11″) used for interior stairs. The width of the step may be wider, but no less than 11″. If the surface area may become slippery when wet, each step should be textured or have some sort of traction strip to prevent falls. Stairs may be made with a variety of materials, including wood, stone, brick, poured concrete, and pavers, Figure 15-5. Walls Walls may be used for multiple purposes, including providing privacy, creating borders, confi ning pets, directing the eye to a focal point, or blocking an undesirable view. Walls may be created with a single type of material or a combination of materials. Hardscape walls are typically made from wood or wood composites. They may also be made from many of the same materials used for patios and other hardscapes. Retaining Walls A retaining wall is a structure that holds or retains the soil behind it to reduce soil loss through erosion as well as mitigate other soil moisture concerns, Figure 15-6. This type of wall is often used on sloped sites to increase the useful- ness of an area by creating terraces with fl at surfaces. A retaining wall may also be used to protect the roots of an existing tree before and after the landscape is installed. A low retaining wall (less than 1′) is often more aesthetic than func- tional. It may, however, be used to border a raised area and even provide seating if wide enough. The National Concrete Masonry Association provides instruc- tions and diagrams on their website for building retaining walls. Manfred Ruckszio/Shutterstock.com Figure 15-5. Creative or unusual outdoor steps can be focal points that attract attention and guide visitors through the landscape. The materials used should complement both the landscape and structures, such as a home. Manfred Ruckszio/Shutterstock.com aodaodaodaod/Shutterstock.com