Stacked Stone Wall: Mortar or Mortarless?
A stacked stone wall adds beauty to your landscape as a border between a garden and a driveway or patio. A stone wall can also prevent soil erosion and landslides. Read on to decide whether a dry stack stone wall or a mortared wall will fulfill your needs best.
Use mortar in your stone retaining wall if it must prevent soil erosion from water or wind. It can also act as a barrier atop a slope or ravine. Strengthen the wall with the mortar so it can withstand pressure from behind, above and below. Also be sure to build your mortared wall on a firmly packed soil foundation reinforced with gravel for drainage. You can build interlocking stone walls, solidified with mortar, up to 16 feet tall.
Interlocking stone systems have stones with a overlapping lip facing downward at the rear of each stone. When soil presses up against the back of the wall it forces the stones closer to those in the layer below. Make mortarless walls, with a soil embankment on one side, no more than 48 inches high. Freestanding mortarless walls should be at most 28 inches tall. For stability, lay plastic-coated geogrid mesh between the stones at every other level in these walls.