If you re building a retaining wall use a blended mason mix which includes the heavy duty mortar type s masonry cement and graded sand.
Building a rock wall with mortar.
This prevents mortar from running down the face of the wall.
Ask a stone yard to help determine how much material you ll need and have it delivered as close to the site as possible.
This is high strength contractor grade and pre blended mortar.
Apply mortar to seal in the top stones.
For projects that don t require a lot of mortar use smaller bags of mortar mix or concrete.
It must be deeper than the frost line or at least 12 inches deep for a 3 foot high wall.
Fill in with mortar any gaps between the rocks on the inside of the wall so that there is no air inside the rock wall whatsoever.
Building a retaining wall is suitable for diyers as long as the wall is a maximum of 3 feet tall in most areas.
This is also ideal for stone columns.
After spreading the mortar but before laying the next stone use the trowel edge to cut the mortar even with wall face.
Anything taller should be handled by professionals.
Once built you ll have a rock solid retaining wall without all the heavy mortar lines.
How to build a rock wall 1.
Wipe any excess mortar from the rocks.
The easiest way to build a stone retaining wall is to use the dry stack method that requires no mortar between stones and does not need a concrete footing like mortared walls do.
Select flat rocks that are flat on one side to be top stones.
Dig a trench that s below the frost line and 2 feet wider than the wall.
Place the top stones as the last layer of rock taking care to make the top of the wall as flat as possible.
Tamp the gravel in the bottom of the trench and pour at least 8 inches of concrete.
The key to building a wall using mortar is when you apply the mortar it needs to go evenly onto the run of stones that are set.
Some good tips about making rock walls that will help build your confidence.
Prepare the footing photo by russell kaye.
A mortar wall must be built on a firm foundation or its joints will crack.