The following are the basic steps involved in constructing a segmental retaining wall. These wallls are designed for vertical walls up to 21" tall or 8° batter (slope) walls up to 42°.
Step 1 - Excavation:
Call your local utilites company to be sure that it is safe to dig. Mark the area of the wall with chalk or spray paint. Dig out a trench along this line. If your wall will be 1-3 courses high, dig the trench deep enough to bury half of the first course of blocks, plus 6" (150 mm) for the compacted base material. If your wall will be 4 or more courses high, dig the trench deep enough to bury the entire first course of blocks, plus 6" (150 mm) for the compacted base material. The width of your trench should be 12" plus the depth of the blocks you choose - this will allow for drain rock behind the wall. Firmly compact the soil in the bottom of the trench.
Step 2 - Base Preparation:
Lay 6" (150 mm) of 5/8 minus or 3/4 minus crushed rock in the trench. Tamp (compact) this base and level it from front-to-back and side-to-side. If you are adding a perforated drain pipe behind your wall, lay landscape fabric across the bottom and back of the trench leaving an extra 12" (30 cm) at the top of the bank (this will be folded over the completed drainage fill). Then lay a 4" perforated drain pipe behind where the back of the wall will go. The drain pipe should slope 1" (25 mm) for every 4' (1.2 m) towards the drainage area.
Step 3 - Choose a Block Size:
Choose from one of our segmental retaining wall products.
Step 4 - Place the First Course:
Set the first unit, making sure that it is level. Lay additional units, checking front to back and side to side alignment with the first unit.
Step 6a - Lay additional courses:
When installing additional units, choose a width that will span the joint of the units below.
Step 7 - Backfilling:
After each two (2) courses are laid, backfill behind the wall with 3/4" drain rock. This step is important to promote drainage and to prevent soil from leaching through the wall face.
Step 8 - Place Cap Units:
A layer of concrete adhesive must be applied to the top course in order to fix the cap units in place. Place the cap unit firmly on top of the adhesive, ensuring both surfaces are free of debris, and apply pressure to secure. Follow adhesive use guidelines.
Step 9 - Finish Grading:
Fold the excess landscape fabric over the top of the drain rock and extend it up the back face of the top course. Cover the landscape fabric with topsoil, mulch, or grass. Slope the surface above and below the wall to ensure water will flow away from and not accumulate near the wall units. If installing pavers above the wall, be sure that the compactor stays at least 40" (1.0 m) away from the back of the top course.