Segmental Retaining Walls (SRW) are very popular for residential, commercial and governmental projects. When a designer combines the strength of an Allan Block SRW wall facing with layers of geogrid, there is virtually no height or project limitation. This is a simplistic statement because there are of course many other things to be considered when designing walls such as soils, compaction, surcharges and others.
But let’s discuss the wall at your house. How do you know if your wall needs geogrid? The Allan Block Residential Walls Guide covers everything you need to know about residential walls less than 6ft in height.
The maximum wall height chart will tell you if your wall, based on its height, soil conditions and surcharge can be built without geogrid. If your wall does not fit the parameters laid out in this chart, your wall is either too tall or has too much load to hold up, or both and will require layers of geogrid.
Geogrid installation starts on page 22 and will describe in easy to use instructions on how to use it. The Soil Reinforcement Chart will tell you how long and at what block course each layer should be placed.
Lastly, let's discuss what geogrid is. Simply it is a polyester woven grid with a polymer coating that will protect it from deteriorating over time. It is laid horizontally between every other block course, back into the soil. When multiple layers of grid are used the wall facing, grid and compacted soils within the grid zone form what the industry calls a reinforced mass. This reinforced mass now works together as a single unit to resist all the forces from the soil behind and surcharges above.
Geogrid is super easy to use and provided so much extra strength to your wall that using it on any wall make sense. So why not use it! It is readily available at your Allan Block dealers and is very inexpensive relative to the total cost of your project.