A mortar wall must be built on a firm foundation or its joints will crack.
Natural stone retaining wall with mortar.
Dry fit each stone first to see that the vertical joints are staggered and the outside faces just touch the line.
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.
For projects that don t require a lot of mortar use smaller bags of mortar mix or concrete.
The face stones visible edges should rest only on stone not mortar so scrape away any mortar that squeezes out.
It must be deeper than the frost line or at least 12 inches deep for a 3 foot high wall.
Type s is the common choice for many below grade applications such as masonry foundations manholes retaining walls and sewers as well as at grade projects like brick patios and walkways.
Although type s mortar must have a minimum compressive strength of 1 800 psi it is often mixed for strengths between 2 300 and 3 000 psi.
Tamp the gravel in the bottom of the trench and pour at least 8 inches of concrete.
Remove the stone spread a trowelful of mortar on the wall and tamp the stone into it with a mallet.
Building a retaining wall is suitable for diyers as long as the wall is a maximum of 3 feet tall in most areas.
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.
This is also ideal for stone columns.
Dig a trench about 6 inches wider than your wall.
Mortar is not always necessary but it is especially.