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 rock wall with mortar.
Dig a trench about 6 inches wider than your wall.
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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.
Apply mortar to seal in the top stones.
Continue in this way so that eventually the pier formwork is full of stone some of it poking up above the formwork so that there will be no obvious course in the wall.
Prepare the footing photo by russell kaye.
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.
Building a retaining wall is suitable for diyers as long as the wall is a maximum of 3 feet tall in most areas.
Once built you ll have a rock solid retaining wall without all the heavy mortar lines.
Ask a stone yard to help determine how much material you ll need and have it delivered as close to the site as possible.
Some good tips about making rock walls that will help build your confidence.
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 high strength contractor grade and pre blended mortar.
Dig a trench that s below the frost line and 2 feet wider than the wall.
A mortar wall must be built on a firm foundation or its joints will crack.
Wipe any excess mortar from the rocks.
How to build a rock wall 1.
Place the top stones as the last layer of rock taking care to make the top of the wall as flat as possible.
It must be deeper than the frost line or at least 12 inches deep for a 3 foot high wall.
Select flat rocks that are flat on one side to be top stones.
After spreading the mortar but before laying the next stone use the trowel edge to cut the mortar even with wall face.
Tamp the gravel in the bottom of the trench and pour at least 8 inches of concrete.
For projects that don t require a lot of mortar use smaller bags of mortar mix or concrete.