Building Planters: How to Retain Soil Using AB Courtyard
Use AB Courtyard blocks to build a garden planter, raised flower beds or a sunken patio area that takes your outdoor living area to the next level. Use these simple instructions to build a patio wall that can retain soil up to 2 courses high.
Layout the Wall
Level the Base Trench
Level Base Course Blocks
Install Second Course
Fill Block Cores
Install and Secure Caps
Backfill Behind Wall
Step 1: Layout
Create a Patio Wall
Create a Planting Area
Determine the location of the wall panel and lay the first course of block to determine the shape of the wall and to establish where to dig the trench. AB Dublin, AB York or both blocks together can be used for the base course. For wall panels with curves, see How-to Sheet: #130 Building Curves and Sepentines. For wall panels with corners, see How-to Sheet #180 Building Corners.
Step 2: Build Foundation*
Mark the location of the wall with a shovel, remove the blocks, sod and other surface materials. Dig a level trench 8 in. deep and 12 in. wide (200 mm x 300 mm). On sloped sites, “step up” the base when it gets more than 6 in. (150 mm) deep. See more on step ups.
Block Placement for Retaining Soil on a Slope
Block Placement for Retaining Soil on a Level Site
Step 3: Fill
Place 6 in. (150 mm) of base rock in the trench and compact using a hand tamper.
*NOTE: The soil beneath the foundation pad must be a good quality compactable material. If soft soils are encountered, they will need to be removed and replaced with additional base rock. A good foundation will ensure a stable wall for years to come.
Base Rock: Using the proper materials to create the base foundation for the panels is important when building on soil. We recommend using a compactible base rock material that is gravel in varying sizes of angular or smooth aggregates similar to the wall rock used in retaining walls or a road/ paver base type material.
Step 4: Level
Level the base rock. We recommend using a 2x4 and a level to ensure the entire base is level. Make any adjustments as needed by adding or removing base rock.
Step 5: Build
Place 3-5 blocks in the trench, with the raised rings facing up, leveling each block as you go. The raised rings on the top of the blocks lock the courses together. Using base rock, fill the block openings. Sweep the top of the blocks and install 3-5 blocks of the 2nd course. Installing the first two courses at the same time will ensure that the blocks line up properly.
Step 6: Build Next Section
Install the next section of the base course, leveling each block as you go. Fill all the block openings for the first and second course with base rock, then sweep the top of the blocks clean. Install the next section of the second course of blocks, offsetting the block seams from the course below then install base rock in the block openings. Use these steps, continue building the first and second course in sections for the length of the wall. Learn more helpful tips on building with AB Courtyard.
Step 7: Wall Caps
Finish the wall with Wall Caps. On straight sections alternate the direction of the Wall Cap. On curved walls, place the short side of the caps on the inside of the curve. Secure the Wall Caps in place with a bead of flexible concrete adhesive along both sides of the raised rings and along the side of each Wall Cap. Completing the entire AB Courtyard wall prior to backfilling the retained soil is recommended.
Step 8: Backfilling and Compaction
With the AB Courtyard wall finished and Wall Caps glued in place, backfill 6 in. (150 mm) of soil behind the block up to the top of the first course. Use a hand tamper to carefully compact soil thoroughly. Install another 6 in. (150 mm) of soil up to the top of the second course, again use a hand tamper to compact soil in place.
Stepping Up the Base Course: Building Step-Ups into the Slope
Building Step-Ups into the Slope
This can be easily done, by extending the base trench into the slope far enough to bury one block for each step up that is needed. Then continue with Step 3 and fill trench with base rock and compact to create a solid foundation.
- AB Courtyard can be built taller than two courses, but only a maximum height of two block courses can be used to retain soil. Learn More on stability options, or to retain soil taller than shown here, see our Retaining Walls Installation Guide for walls up to 6 ft. (1.8 m) tall using our retaining wall products.
- If building your wall panel with posts/pillars, interlock them together for added stability. See How-to sheet #230 Interlocking Walls & Posts.