Retaining Walls are an aesthetic addition to any garden, backyard, or even commercial applications. They bring a certain elegance to a setting while also serving the essential purpose of holding back the soil in an elevation change. Though there are many different styles and colors to consider, there are only a few kinds of products to consider when building the wall: Natural Stones, Manufactured Segmental Wall Stones, Masonry Block Units, or Poured Concrete. In this blog, we will be covering the differences between Natural and Segmental wall stones. The decision of which, will come down to appearance, function, and installation.
When it comes to appearance, neither is necessarily better, as it comes down to your personal preference. A dry stacked Natural Stone retaining wall is one that would fit better in a garden scenario. It looks more like a natural structure and can blend in with the backdrop more easily. On the other hand, the manufactured Segmental Wall Stones provide a more sleek and modern look with geometric patterns and blended colors.
The decision of which wall to use will heavily be influenced by what function needs to be accomplished. Both types of walls retain soil and assist in an elevation change, but Segmental retaining walls are able to be used in larger walls than the Natural Stones. Natural Stone walls are considered useful only up to a maximum of 5' in ideal conditions; any higher than that and the wall is considered unsafe and may topple due to the force of the soil. Segmental retaining walls can be used in scenarios with much higher elevation change. Theoretically, they do not have a height limit assuming perfect installation and conditions.
The installation methods of both walls are quite different, especially when the height of the wall is considered. Natural Stone walls need to be seated around 6”-8” below grade and seated around a clean stone to allow for drainage. As the wall is built up, it needs to be backfilled with more drainage stone every 6” or so. Doing this ensures that the wall can resist water flow and provides stability. Segmental Walls on the other hand require a little more care when installing them. They start with roughly the same idea as Natural Stone walls but once they get over 3’ high, geo-grid must be used to provide additional support. Geo-grid is a thick, net-like mesh that is laid parallel to the ground and extending back into the soil behind the wall. This supports the soil even further to help prevent shifting. The Segmental Wall stones may also be laid with a slight angle to allow the entire wall to angle backwards slightly up and into the soil behind it. This, again provides more stability and can help the wall become immune to the flexing and contracting of the soil during freezes and thaws. Segmental retaining walls exceeding certain heights may also require geotechnical engineering and approval by your township or borough.
Both types of wall material are unique and useful in certain situations. The Natural Stone walls provide a subtle and natural look to any garden or backyard walls, while the Segmental retaining walls have a more uniform and ordered look and can be used in much larger applications such as commercial retaining walls. Here at Landis Block we offer a select variety of Natural Stone retaining walls from a few Pennsylvania Quarries and we manufacture the segmental retaining wall for Cambridge Wall Systems.