Excavation and Installing Base Course

The base course of your patterned retaining wall should always be installed using a full course of full-sized blocks. This will speed the leveling and installation of the first course of the pattern.

• Refer to the basic retaining wall instructions for a detailed description on how to install the base course. Basic steps include: site prep and excavation, installing base material, base course, wall rock, backfill materials and compacting.

Video: Build a patterned retaining wall

AB Abbey Blend Pattern Retaining Wall

Installing Reinforcement in Patterned Walls

• Check your approved plans for exact size and course location for the AB Reinforcement Grid.
• Install the first layer of geogrid by placing the edge of the geogrid against the back of the raised front lip and rolling it out along the wall.

Install the Multi-Course Pattern

The retaining wall photos shown here use AB Reinforcement Grid and a two (2) course pattern.

Bi-Axial AB Reinforcement Grid^™

Install geogrid reinforcement

• Stack the first course of the pattern on top of the geogrid and the base course.
• Check blocks for level, and make adjustments as needed. Pull on the back of the geogrid to remove any slack. If necessary, stake in place.
• Install the wall rock in the block cores and 12 in. (300 mm) behind the blocks to the height of the blocks.
• Compact inside the block cores using a shovel handle. Check blocks for level. Learn more about compaction in the block cores.
• Use infill or approved on-site soils to backfill behind the wall rock in 8 in. (200 mm) lifts or less. The top of the blocks will not always match up with each lift of soil. Check blocks for level.
• Using a plate compactor, compact the wall rock and infill materials behind the block in 8 in. (200 mm) lifts or less. Compact directly behind the blocks in a path parallel to the wall, working from the back of the wall to the back of the excavated area. Always make a minimum of two passes with a plate compactor.
• Install the remainder of the 2 course pattern. Install wall rock in the block cores and behind the blocks as before so they are level with the top course of the blocks. Use infill or approved on-soils to backfill behind wall rock. Check blocks for level. If using a custom pattern, remember to offset the vertical seams by at least 1/4 of the block whenever possible.
• With the first multiple-course pattern completed, use a plate compactor to compact the wall rock in the block cores and directly behind the blocks. The first pass of the plate compactor should be directly over the top of the block cores.
• Compact in a path parallel to the wall, working from the front of the block to the back of the excavated area. Make a minimum of two passes with a plate compactor. Check blocks for level.
• Keep all heavy equipment at least 3 ft.(0.9 m) away from the back of the wall.

Install first course of pattern on top of geogrid

Install wall rock and compact behind retaining wall block

Installing the Second Multiple-Course Pattern

• Install the next pattern section as done in the previous steps. Each additional pattern will need to be offset from the pattern below to avoid a repetitive look. Remember to offset the vertical seams by at least 1/4 of the block whenever possible.
• Two course patterns should be selected for most projects. Three course patterns can be used for gravity walls or to top off a reinforced wall where geogrid is not required within the top three courses.

Ending and Topping off the Retaining Wall

Patterned walls may be ended with a step-down or a turn-in. When ending a patterned wall you will need to modify the pattern and randomly adjust as necessary to create the look desired.

• Finishing a patterned wall is the same as finishing a standard retaining wall. The only requirement is that a multiple course pattern must be completed so that the top course of blocks forms a level surface.
• On the last course, fill behind the blocks with organic soils in place of infill or approved on-site soils. This will assist in any plantings above the wall and also to direct water from running behind the blocks

Offset the patterns

Ending patterned retaining walls

Finish retaining wall pattern, level and align

Compact on block and behind retaining wall

Compacting Patterned Retaining Walls

• Compaction in the block cores needs to be done regularly when working with patterned walls. This can be done by using the end of a shovel to compact the wall rock, adding additional rock if necessary.
• At each 8 in. (200 mm) lift, compact the block cores with the end of a shovel, and the area directly behind the block with a plate compactor.
• At the conclusion of each pattern, the top of the wall will be level. Run the plate compactor over the top of the blocks to consolidate the wall rock. Place geogrid if required, and begin the next pattern.

Compact retaining wall with shovel

Install next layer of geogrid

Construction Tips for Patterned Retaining Walls

Patterned walls resemble hand-laid stone walls, and will require a certain level of detail and craftsmanship to construct. Some custom fitting of blocks will be required. Plan on taking a little extra time to build, particularly when building one for the first time.

• When building an AB Ashlar Blend retaining wall, if an AB Junior Lite is not available, AB Lite Stones can be cut to produce two (2) AB Half Lites. It is good practice to pre-cut the desired number of blocks ahead of time to speed up the installation process.
• Offset each new pattern from the pattern below to maintain the "random" appearance.
• Use a two (2) course pattern on retaining walls that have numerous inside and outside curves. This will speed up the installation process.
• Use the two (2) course pattern when building a patterned curve. It is easier to work with than the three (3) course pattern. Learn how to build curves with this easy step-by-step process. To build tighter inside or outside curves learn how here.
• When building curves, the 2 course pattern is easier to work with than the 3 course pattern.

Install next section of pattern

Combining retaining wall patterns