Multi-height retaining wall systems (MHRWS) use standard segmental units like Anchor• Highland Stone???(R)???AE???? (Pavestone, pictured) to create unique looks for wall facing. Spacing out common bond lines makes the wall look more natural and adds appeal to hardscape projects.

Retaining walls are a cost effective solution to changes in surface grading, complementing the landscape with stone blocks infused with rich colors and crafted to feature exposed aggregates.

Combining multiple heights and sizes, multi height retaining wall systems (MHRWS) evoke the random, natural look of hand-stacked stone walls.

Before construction, stake out the wall's location, taking into account the system batter for the top of the wall. Excavate for the leveling pad to the lines and grades shown on the approved plans, and excavate enough soil behind the wall for reinforcement material. The trench for the leveling pad should be a minimum of 24 inches wide and 12 inches deep for a 12-inch front-to-back dimensional block.

Panel Construction
Panels are a quick way to build a multi-height wall by combining variant vertical retaining wall blocks in a simple installation pattern. This installation pattern is relatively easy to install on any scale.

Start by using an equal number of units of each face size; for example, let's use a 6"x6", 6"x12" and 6"x18". Start by using all three units of 6-inch product. Next, use all three units of the 3-inch product and stack them on the first three units staggering the bond. This completes panel one.

Next, working along the wall, use all three units of the alternate-sized product. Backfill, compact, and install a grid or structural backfill if needed. Use alternate product and stack units on the course as described before, staggering the bond. Start the next set of panels by staggering the first unit to the right or left of lower panels, then repeat the process. Continue adding panels until the wall is complete.

If the wall needs reinforcement, check the construction plan for which courses will need the reinforcement grid. Measure and cut the reinforcement grid to the necessary length and lay it perpendicular to the wall, according to the design strength direction. Place the front edge of the material on the course, 1 ???(R)???AE?-inches from the face of the block. Apply the next course of blocks to secure it in place. Pull the reinforcement taut and pin the back edge in place with stakes.

Check with local producers for availability, panel layout and estimating information.

MHRWS blocks are typically manufactured from a "no slump" concrete mix under high frequency vibrations and extreme pressure. The Diamond Pro Stone Cut???(R)???AE???? and Highland Stone???(R)???AE???? shown have a compressive strength greater than 3,500 psi and a maximum water absorption of 7 percent that will meet or exceed ASTM 1372.

After reaching the finished height, establish a finish grade and check for surface drainage. To minimize infiltration of water into the top of the backfill area, add a minimum 6 inches of soil with low permeability (clay or similar materials).

Leveling Pads & Installation
The leveling pad typically consists of a crushed aggregate compactable base material, with a 3/4-inch maximum top size aggregate minus with fines. The pad must extend 6 inches in front and behind the first course of block and be at least 6 inches deep.

Excavate for the leveling pad to the lines and grades shown on the approved plans, and excavate enough soil behind the wall for reinforcement material. The trench for the leveling pad should be a minimum of 24 inches wide and 12 inches deep for a 12-inch front-to-back dimensional block.

Compact the aggregate and make sure it is level. A string line should be run along the back of the block to align the wall units when installing the base course. Use the highest MHRWS vertical thickness blocks only in the lowest course in the elevation of the wall. Place the blocks side-by-side, flush against each other, and in full contact with the leveling pad. Level the blocks front to back and side to side. Check the blocks for proper alignment.

Walls require at least 12 inches of free-draining aggregate, and can be reinforced with a geosynthetic web, as shown in the diagram. Minimize water infiltration into the top of the backfill area with 6 inches of low-permeability soil, e.g. clay.

Place the second course of stones on the base course while maintaining staggered bond, and push each block as far as possible to ensure the correct setback. Fill all voids between and within concrete wall units with drainage aggregate. Use of a filter fabric may be required, which should be placed directly behind the wall extending from the bottom of the base course to the middle of the top course.

Backfill with a minimum of 12 inches of drainage aggregate directly behind the block, and fill in soil behind the aggregate. Compact the backfill before laying the next course. For drainage design, place the drain tile as low as possible behind the wall, so water drains down and away from the wall into a storm drain, or to an area lower than the wall.

Multi height retaining wall systems are innovative way of taking standard sizes of segmental retaining walls and creating new and different looks to the wall facing.