Top 6 retaining wall construction mistakes

  • 3 minutes
  • 9 September 2021

Correct retaining wall selection and installation is crucial to ensure your modular retaining wall will withstand the test of time. All too often, retaining walls have incorrect drainage, incorrect panels or no waterproofing! So, to ensure a seamless retaining process, we’ve listed the Top 6 Retaining Wall Construction Mistakes so that you can avoid them!

Kate Sparks Retaining Wall Construction

Mistake 1: Incorrect panel 

Whether installing a standalone or integrated retaining wall, it’s vital to start your retaining wall off correctly. So, it’s essential you or your installer order the right retaining system for your required retaining loads. For example,  

  • TerraFirm50 panel can retain up to 500mm 
  • TerraFirm75 panel can retain up to 750mm 
  • TerraFirmPro panel can retain up to 1.8m 

Every retaining project will have different requirements, so please seek further advice on which retaining system will be best for your project. 

Mistake 2: Incorrect footing depth 

As mentioned above, not only do you need the right panel, but it’s also critical that the footing depths are correct. The footing depths are determined by the retaining loads and soil type and play an essential role in any retaining wall as the retaining load is transferred back into the posts. Therefore, this is definitely a retaining wall construction mistake to avoid.  

Mistake 3: Incorrect post alignment   

The next retaining wall construction mistake is one you may not be aware of, and that’s incorrect post alignment. Posts need to be set at the specified one-degree back angle (back towards the retaining load) when installing a retaining wall. Positioning the posts back towards the retaining load allows for some inevitable settlement in your retaining wall foundations.

Mistake 4: Incorrect drainage  

A vital part of installing a retaining wall is drainage; however, we often see retaining walls with insufficient drainage or no drainage at all! By not installing sufficient drainage, water can’t escape from behind the wall, essentially creating a dam. Therefore, water will dam behind the wall (particularly with heavy rains) and overload the retaining wall causing possible failure.

Mistake 5: Not applying waterproof sealant before backfilling 

Prolonged moisture to the rear of an unsealed retaining wall may cause a shortened life expectancy. Therefore, another critical step in the installation process is waterproofing to the retaining side or your Modular retaining wall (as per Modular Walls recommendations). 

Mistake 6: Incorrect backfill material

Using incorrect backfill is also another common retaining wall construction mistake. Backfill or drainage gravel should be granular and roughly 10-20mm in size. Backfill is a crucial component of retaining walls as it allows water to enter the agriculture pipe (ag pipe) correctly. Incorrect backfill will lead to insufficient drainage which could cause the wall to be overloaded and fail.

Backfilling - How To Build A DIY Retaining Wall | ModularWalls

Overall, by avoiding these six retaining wall construction mistakes, you will be on track for a retaining wall that looks fantastic and is well constructed. Plus, you will get to enjoy your new yard for many years to come.