September 8, 2017

How can I tell if reinforcement is needed in my retaining wall?

Written By: Rich Lovdal
 Allan Block retaining walls like all segmental retaining wall system can be stacked up to a certain  height and work fine without additional need for geogrid reinforcement.  But how do we determine what that certain height is?  Many municipalities around North America say a wall needs an engineer’s stamp if the height exceeds 4 ft.  This fact does not say that any wall under 4 ft can be a built as a gravity wall (a wall that has no additional geogrid reinforcement to increase its stability). From an engineering sense, the question of when geogrid is required is dependent on many things such as block weight, block depth, block setback, soil parameters, surcharges above the wall, slopes above the wall fences above the wall, local codes and others.  As you can see it is not just a matter of the municipality engineering height limit.

On Page 12 of the Allan Block Residential Walls Guide you will find a comprehensive Gravity Wall Height Chart for all of the Allan Block retaining wall products.

If your wall does not easily fit into these limits Allan Block would recommend using geogrid reinforcement in your wall.  On Page 24 of the Allan Block Residential Walls Guide you will find the start of the geogrid section and on page 25 you will find an estimating chart that will discuss how best to use geogrid in your wall.

For more information contact Allan Block at