It must be deeper than the frost line or at least 12 inches deep for a 3 foot high wall.
Building a rock wall with mortar.
Wipe any excess mortar from the rocks.
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.
This is high strength contractor grade and pre blended mortar.
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.
Ask a stone yard to help determine how much material you ll need and have it delivered as close to the site as possible.
Apply mortar to seal in the top stones.
This is also ideal for stone columns.
Dig a trench about 6 inches wider than your wall.
Prepare the footing photo by russell kaye.
Place the top stones as the last layer of rock taking care to make the top of the wall as flat as possible.
How to build a rock wall 1.
After spreading the mortar but before laying the next stone use the trowel edge to cut the mortar even with wall face.
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.
Dig a trench that s below the frost line and 2 feet wider than the wall.
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.
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.
New videos added march 2018 much more detail in the masonry playlist at https.
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.
Once built you ll have a rock solid retaining wall without all the heavy mortar lines.
Anything taller should be handled by professionals.
Building a retaining wall is suitable for diyers as long as the wall is a maximum of 3 feet tall in most areas.
Select flat rocks that are flat on one side to be top stones.