A retaining wall is a wonderful way to improve your yard both aesthetically and practically. Yet those who install a retaining wall without proper foresight often end up with unforeseen problems down the line. If you have been considering augmenting your yard with a retaining wall, keep reading. Here you will learn three key tips to ensure long lasting, attractive results.
Don't exceed three feet.
A retaining wall is unlike freestanding walls in that it must be capable of holding back the enormous amount of soil located on its back side. Landscaping engineers refer to this mass of soil as failure plane. The taller a retaining wall, the greater the pressure being exerted on it by the failure plane. In other words, taller walls require more thorough engineering in order to withstand pressure from the failure plane.
For that reason, unless you are a professional, try not to exceed a maximum height of three feet. Walls taller than that are best left to a landscaper with the requisite engineering know-how. Be aware that your three foot limit applies to more than just the visible portion of your retaining wall; it also includes the foundation and whatever portion of the wall lies below the surface of the ground.
Install a gravel drainage field behind the wall.
This tip is especially important for those who live in parts of the country where the weather regularly drops below freezing in wintertime. You see, those sub-zero temperatures cause water in the ground to freeze and expand. This increases the volume of the soil.
In the absence of a retaining wall, this expansion will push the soil upward. But soil located in a failure plane will instead press outward against the relatively lower resistance of the wall. As a result, you may find your wall developing cracks, tilts, or other signs of pressure-related damage. Eventually such pressure may even cause your wall to collapse entirely.
The good news is that you can negate the ill-effects of freezing soil by installing a layer of gravel aggregate along the back of your retaining wall. This gravel has two positive effects. For one thing, it provides a physical buffer between damp soil and your wall. Second, it promotes a greater degree of drainage. This lowers the amount of water in the soil. Consequently, the expansive forces at play when the ground freezes will be kept at a bare minimum.