U&M Group

All About Building a Retaining Wall

Wednesday, August 19th, 2020 AT 11:43AM

In an ideal world, all buildings would be situated on level, stable ground, but of course, that isn’t always possible. One of the problems of building on a slope is that the soil can move — and this might mean you need a retaining wall.

What Is a Retaining Wall?

A retaining wall is a wall, either vertical or near-vertical, built to prevent slipping or erosion of soil that could damage a structure — such as your home. It can be incorporated as part of the main building or be free-standing, and it may have a parapet on top for extra safety.

A retaining wall may sometimes be subject to planning permission or building regulation approval. In general, a wall that’s more than 2 metres in height (1 metre if next to a road or path) will require planning permission. On the other hand, a freestanding wall may not need building regulation approval, though if it’s a boundary wall it could come under the Party Wall Act.

Why Might Building a Retaining Wall Be Necessary?

The most common reason for building a retaining wall is that your property is on a slope where the soil is unstable. This could involve the risk of material coming down the slope onto your property, perhaps ending up piled again the walls of your home.

Alternatively, there may be water often coming down the slope. A retaining wall can help to contain this, but the water can create problems for the wall itself by increasing the pressure on it. In this case, some form of drainage may need to be built into the wall.

Erosion can also be a problem if your property is on a steep slope or near the edge of a cliff. A retaining wall may be able to reduce the amount of erosion, protecting your home.

What Materials Can Be Used for Building a Retaining Wall?

Although a wide range of materials can be used for a retaining wall (including wood, plastic or even earth), the most common materials are brick, stone and concrete.

The biggest drawback of brick or stone is that they’re only as strong as the mortar holding them together. They can certainly be built to be robust enough to withstand the pressure on them, but this may require reinforcement. For example, stainless steel anchors can be driven into the ground, with the other end either hidden inside the wall or with domed nuts used as a feature. This can often enhance period walls that need to be strengthened.

A concrete retaining wall, on the other hand, can be made up of either concrete piles or beams. Alternatively, steel-reinforced or cast-in-place concrete can be strengthened by slab foundations, sending the lateral pressure down into the ground.

If you think your property might need a retaining wall, or you want to know more, you’re very welcome to get in touch with us.

You can also check out one of our previous projects here in which we built a contiguous piled retaining wall for a client who wanted a new garden room and pool building in Kingston, London.