Retaining walls provide support for soil that is on a vertical slope. Some retaining walls keep your home and landscape from sliding down a hillside or into a stream. Others are necessary to prevent drainage or erosion problems. Some are also used as a sound barrier, like next to a highway.
A retaining wall can increase the beauty of the site as well as serve a practical purpose. Uneven terrain can add visual interest and variety in the landscape. Changes in grade may be used for recreational and gardening areas, as well as to provide proper surface drainage. Color and shape of rock used should be carefully incorporated to unify a design with the overall landscape.
There are several things you should consider in construction of retaining walls to reduce grade or slope. The wall will usually be more stable if developed into a gentle curve. In informal landscaping, curved lines tend to be more pleasing to the eye than straight lines, while straight walls may need to be bolstered with columns or jogs to improve stability.
Materials you can use for wall construction include: native stone, ledge rock, brick, tile, broken concrete, concrete blocks and railroad ties. If you are building a stone retaining wall, the type and quality of the stones are important. Some stones are very hard and resist weathering while others, such as shale, are soft and will crumble.
Retaining wall design and wall type selection is driven by several factors. These factors include cost, required wall height, speed of construction, ground water conditions and soil characteristics. Any wall over three feet high will need special requirements and most likely require a professional.