Most retaining walls can be used to build walls up to 3 ft tall. Majority of these walls can me made taller with the use of Geo-grid. It has to be used in walls taller then 3 ft and it ties a minimum of 3 ft into the grade behind the wall. By using this material you can increase the height of your walls without losing the structural integrity of the wall. Geo-grid can be used with all types of wall stone made by any manufacturer. I would not recommend building any walls taller then 3 ft without it. Unless you are using a bigger stone that has been engineer approved for taller applications.