Using Retaining Walls In Your Garden

It is relatively easy to make your garden more beautiful by building a retaining wall, which has a lawn or area of flowers behind it. A retaining wall needs to be strong enough to withstand the pressure of soil weight behind it. It must also be porous enough to allow adequate drainage. Walls made of either dressed stone or rubble are the most popular. When using stone for your retaining wall, you can choose from between two kinds of construction. Dry-wall construction uses earth as filler between the stones. Mortar construction uses cement as the bonding agent.

It is important for the base of a retaining wall to be below the front line, or about six inches down in the northern parts of the United States. For a wall without buttresses or projections, the width of the base should be one-quarter the height of the wall. Walls can taper to a width of about one-quarter of the base width. Walls with buttresses should have bases that are one-quarter as wide as the wall is high. This measurement refers to the widest points of the wall where the buttress will be used. In narrower places the base can be of a thinner proportion.

Every 24 inches and approximately six inches from the lower ground level of the wall, you should embed drainage pipes. If the wall material itself is sufficiently porous, it may be possible to eliminate the need for the drains. In any construction that uses mortar, however, drainage pipes are critical. It is possible to begin at ground level with dry-wall construction rather than six inches below the frost line, but this is not generally recommended.

The cheapest way to construct a dry wall is to select local stone. You can pick larger stones for the main construction and smaller stones for the chinks. The largest stones you have should form the base of the retaining wall, with smaller stones rising to the top. The side of the wall that faces out should be as level as possible. Obstructions and edges of exterior stones should face inward. This allows the wall to hold the soil it is to retain and also makes a good appearance. Stones that have rounded surfaces should be eliminated because they do not form good walls.

All the stones should be placed in a good bond, which means that the edges of stones on one rose, or course, should overlap spaces in the lower courses, or rows. If a stone on an upper course does not fit firmly in place, earth and smaller stones can be packed in to improve the bond. There should be no vertical crevices.

The retaining wall itself should slope back, against the soil it is supposed to retain. This provides greater strength to the wall. The width of the base should be one-third of its height. This is a general rule, but in many areas, it is common practice to slope a wall as much as five to six inches for each vertical foot. This degree of slope is not required, however. The soil should be packed firmly in all the walls pockets and continued back in the soil that is being retained.