We tend to take retaining walls for granted. That’s probably because they are so common. But, just like the iceberg, a lot is going on with a retaining wall that’s not obvious. Also, retaining wall designs vary not just because of aesthetics but because different materials and methods are better in certain circumstances. Moreover, without understanding the importance of good retaining wall design, danger could be just around the corner. Retaining wall failure can have disastrous and costly consequences. So, what are the best retaining wall designs, and how do they differ?
Different Retaining Wall Designs
Retaining walls are built with many different materials and styles. However, the clever parts of the design are hidden under and behind the construction. These parts consist of drainage, footings, waterproofing, geotextiles, different sections of backfill materials and surface soils. So, listed below are the main retaining wall designs used for residential projects.
1. Timber or Concrete Sleeper Walls
Sleeper walls are a ubiquitous design. They consist of horizontal timber or concrete sleepers fixed behind vertical steel posts concreted into the ground. Various colours and textures are available to choose from.
Pros – Both materials are cost-effective. The metal posts and concrete sleepers also meet AS4678 (60-year life span). Plus, there are lots of aesthetic options.
Cons – Difficult to construct over rock. Also, gaps between the sleeper allow water to run through. Must be H5 treated timber for durability.
2. Sandstone, Boulder, or Gabion Retaining Wall Designs
These designs use heavy, stable block designs to give the wall incredible strength and durability. In fact, this kind of ‘gravity assisted’ wall is an ancient design, with some still standing today.
Pros – Very strong, durable, and beautiful to look at. Plus, they can be built without foundations.
Cons – Gaps will allow water to run through. Not practical for tight spaces.
3. Linked Block Retaining Walls
Made up of smaller interlocking blocks, linked block walls are popular in gardens.
Pros – Cost-effective and plenty of options for texture and colour. Easy to build without mortar. They don’t require extensive footings. Plus, great for curved retaining walls.
Cons – Requires concrete reinforcement behind the wall. Any wall higher than 800mm requires professional construction.