Retaining walls are essential in landscaping practice to prevent the constant downward movement of soil on slopes, which can result in landslides. They are often built to alter a slope into a series of terraces. But as you should have noticed, there are several kinds of retaining walls, so choosing the right kind of retaining wall is the first step. You would also need to balance the cost, function, and aesthetic aspects of the retaining wall you wish to have built. Here are some of the main kinds of retaining walls.
Boulder retaining walls
Boulder retaining walls can be defined as retaining walls using boulders to retain the soil behind and hold up the terrace. Many boulder retaining walls do not use any cement/mortar to glue the boulders together. Instead, they rely on each stone’s heavy weight to hold the wall together. These boulder retaining walls are of the “gravity wall” type. The base stones are always half buried in the ground to prevent them from moving. The base stones can also be bedded in concrete to further strengthen the wall.
Brick retaining walls
Brick retaining walls are among the most reliable kind of retaining wall, and can be used in patterns like the sawtooth design. Brick retaining walls can be used successfully to create medium-sized window gardens too. Rather than having multiple window boxes, create a sturdy window garden with bricks.
Modular retaining walls
Modular retaining walls are made from dressed stone blocks and concrete, and designed in an interlocking method contrasting with the more linear design of the other kinds of retaining walls. This is the most common kind of retaining wall in heavy construction and can be seen along roadsides where they prevent soil erosion. Dressed stones can be purchased from a quarry, although softer stones can be cut in your home, if you have the suitable tools and know-how.
Timber retaining walls
Wood may not be as durable a choice as concrete or rock for a retaining wall, but they are a quick way to get an edging or retaining wall up. The timber used must be very durable and strong, or else treated with preservatives. Treated timber is given a rating based on their hazard level with H1 being the least durable (and least hazardous) and H6 being the most durable. You can also use old railway sleepers although these are not very durable. The base timber slab should always be set within a prepared bed of drainage material like gravel to slow down decay.
Typical types of timber walls are the:
- straight slab wall
- vertical timber wall
- crib timber wall
Slab walls are defined as placing slabs, sleepers or logs horizontally on top of each other. Vertical timber walls are defined as standing slabs or sleepers placed side by side. The vertical timbers are half buried in the soil to provide stability, from one third to one half their length, and stabilized with concrete around the base. Crib timber walls are alternate layers of notched timber which are then placed at right angles to each other, filling up the notches. The early timber houses were often constructed in this fashion, as this kind of wall design is very strong.
