Retaining Walls offer many purposes including landscape bed redefining as well as holding back a hillside for erosion control.
Salmon Clearwater Landscaping is Allen Block Certified.
- There are multiple styles and colors of block, all serving a specific purpose. Some are only engineered for a couple ft in height while others can go 12ft +. There are caps that can be added to the top of the wall to finish it off also.
- All block walls start with a compacted gravel base, set on a firm foundation. Gravel base is recommended over a concrete base to allow for ground to heave and thaw without compromising the base and then moving the wall, causing the wall to fail.
- A drain system is always recommended to lay behind the wall at the base. A drain system includes a 4in perforated flexible pipe, drain rock and a filter fabric. This will collect water and divert it away from the wall. A water soaked base will allow the wall to be unsettled, blocks can then start to move, become un-level and then the wall will eventually start to lean and tip over.
- Compacted gravel is recommended to lay behind the wall. Gravel depth and distance back behind the wall depends on ground conditions such as slope and vegetation also what the wall is used for..landscape bed defining, holding back a hillside (erosion control). A solid gravel buffer between the wall and the native ground also helps keep ground pressures off the wall.
- After 4 foot tall it is recommended to install a geo-grid netting to help stabilize and anchor the wall. The geo-grid runs the length of the wall and extends 4-6 feet behind the wall. Once laid between block layers and gravel, placed on top of geo-grid and compacted, the wall has a firm hold behind it (a wider base so to speak). The wall becomes locked into the ground. Depending on wall height and ground slope, more layers may be recommended.