Watch this video from This Old House to learn how to build a retaining wall.
1 Dig into hillside 2 ft. back from face of retaining wall.
2 Stretch a level line between wood stakes to establish the wall height.
3 Dig out dirt along base of wall to accommodate 6 inches of crushed stone.
4 Add 6 inches of stone, then compact it with a hand tamper.
5 Add 2 inches of stone dust to create setting bed for base course of blocks; tamp stone dust.
6 Set and level base blocks; pound each block into stone dust with a rubber mallet.
7 Use level to align base course with the mason's line.
8 Backfill behind the base course with crushed stone.
9 Set the blocks in the second course.
10 Install a filter fabric behind the wall.
11 Apply adhesive to adhere the corner block to the base course.
12 Continue setting blocks, making sure the grooves fit over the tongues on the blocks below.
13 Use guillotine splitter to cut rough edge on a cap block to create a corner cap.
14 Set and glue down the corner cap with both rough edges exposed; allow the block to extend 1 inch over the wall.
15 Set the remaining cap blocks using masonry adhesive.
16 Backfill the wall with crushed stone.
17 Fold down the filter fabric, then add 6 inches of loam.