Article by Jayden Solle
A retaining wall is a structure designed and built to resist horizontal pressure of soil when there is a change in ground elevation. There are mainly four different types of retaining walls: a gravity wall, sheet piling wall, cantilevered wall and an anchored wall. Gravity walls rely on their weight to withstand pressure from behind and so are usually made out of cement, stone or other heavy material. It is important to use a very strong material as it will have to resist a high amount of force from the soil. A gravity wall will often have a small setback to enhance stability. Sheet pile retaining walls are usually used in soft soil and tight spaces. They’re usually made out of steel, wooden planks or vinyl and are pushed into the soil. Cantilevered walls use much less material compared to gravity walls: they’re built in the form of an upside down T and are usually made from an internal stem of steel-reinforced, cast-in-place cement or mortared masonry. They are used to cantilever loads to a large, structural footing, transforming horizontal pressures from behind the wall to vertical pressures on the surface below. An anchored wall is similar to all three the above mentioned walls and can be built in any way similar to the abovementioned walls. However, an anchored wall needs additional strength in order to resist the necessary forces. The additional strength will be achieved by adding cables that will stay anchored in the rock or soil behind the wall. This wall is very useful where high loads are expected, or where the wall itself has to be slender and would otherwise be too weak.
So you just bought your dream home: everything is exactly the way you wanted it. The location is perfect for raising children, the house is large enough and the monthly payments aren’t too bad either. There’s just one small problem: your garden is a complete mess. There are no trees or plants in sight; you cannot even see if there have ever been plant beds and some areas have a natural sloping, making it a much bigger challenge to create your ideal garden. How will you fix this mess? Well, other than employing a lawn specialist, you can install a retaining wall in the areas where the level of the land changes. This can create useful flat areas for you to use, as well as prevent erosion.
Building a retaining wall can be quite a challenge. You have to choose the right height, width and material to ensure that it will be able to withstand the forces caused by soil elevation. Building a retaining wall as a DIY project is probably not wise. You need to consider frost heave, pressure from wet soil and the impact of heavy objects close to the wall. When wet soil freezes in cold weather, the soil can push the wall upward and cause it to split. The soil above your wall can become waterlogged after heavy rain, which will cause it to sink or slip away. This can be prevented by the installation of waterflow and drainage pipes in the wall. Placing heavy objects near the wall could cause it to break down, due to the added pressure on the soil.
All these factors need to be considered before even thinking of building a wall yourself. If I may offer you advice, rather get a specialist to build it, or at least ask them to direct you in the right direction.
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For more information on retaining wall, go to http://www.bosun.co.za