| Stake out the wall |
- Have a surveyor stake out the wall’s placement. Verify the locations with the project supervisor.
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| Excavation |
- Excavate for the leveling pad to the lines and grades shown on the approved plans and excavate enough soil behind the wall for the geosynthetic reinforcement material. The trench for the leveling pad should be at least 12 inches wider than the block you are installing and 6 inches deeper than the height of the block. See Diagram 1.
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| Leveling pad |
- An aggregate leveling pad is made of compactible base material of 3/4-inch minus (with fines).
- The pad must extend at least 6 inches in front of and behind the first course of block and be at least 6 inches deep after compaction.
- If the planned grade along the wall front will change elevation, the leveling pad may be stepped up in 6-inch increments to match the grade change. Start at the lowest level and work upward whenever possible.
- Compact the aggregate and make sure it’s level front to back and side to side. Mist lightly with water before compaction. See Diagram 2.
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| Base course |
- This is the most important step in the installation process. Remember, the base course is buried.
- Begin laying base course block at the lowest elevation of the wall. Remove the rear lip of the block by hitting from the back so that it will lie flat on the leveling pad.
- Place first block and level, front to back and side to side; lay subsequent blocks in same manner.
- Place the blocks side by side, flush against each other, and make sure the blocks are in full contact with the leveling pad.
- If the wall is on an incline, don’t slope the blocks; step them up so they remain consistently level.
- Use stringline along back edge of block to check for proper alignment.
- For multipiece products, use the largest unit for the base course.
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| Construction of the next course: single-piece systems |
- Clean any debris off the top of the blocks.
- Place the second course of blocks on top of the base course. Maintain running bond. Pull each block forward as far as possible to ensure the correct setback. See Diagram 3.
- Backfill with drainage aggregate directly behind the block, adding 6 inches at a time followed by proper compaction.
- Add soil fill behind the aggregate. Compact before the next course is laid.
- Don’t drive heavy equipment near the wall. Self-propelled compaction equipment should not be used within 4 feet of the wall.
- You’ll need partial units to stay on bond. A circular saw with a masonry blade is recommended for cutting partial units. Use safety glasses and other protective equipment when cutting.
- If you are using a block with cores that should be filled, fill with drainage aggregate prior to laying the next course. See Diagram 4.
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| Construction of the next course: multipiece systems |
- Clean any debris off the top of the blocks.
- Place the second course of blocks on top of the base course. Maintain running bond. Pull each block forward as far as possible to ensure the correct setback.
- Backfill with drainage aggregate directly behind the block, adding 6 inches at a time followed by proper compaction.
- Add soil fill behind the aggregate. Compact before the next course is laid.
- Don’t drive heavy equipment near the wall. Self-propelled compaction equipment should not be used within 4 feet of the wall.
- You’ll need partial units to stay on bond. A circular saw with a masonry blade is recommended for cutting partial units. Use safety glasses and other protective equipment when cutting.
- If you are using a block with cores that should be filled, fill prior to laying the next course.
- You can install these products using any combination of blocks.
- Keep the wall bond by placing units in a staggered relationship to the course beneath.
- For best results with a rough-hewn-face product, use a filter fabric, which should be placed directly behind the wall extending from the bottom of the base course to the middle of the top course. This will minimize material coming through the rough-hewn face texture of these products. We recommend a non-woven, 4- to 6-ounce fabric. See Diagram 5.
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| Capping |
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Straight wall
Caps are trapezoidal and must be laid alternatively short and long cap faces for a straight line. Always start capping from the lowest elevation.
Outside curves
Lay out the cap units side by side and cut at least every other cap to produce a uniform look. Start with the long side of the cap facing out and adjust to the radius.
Inside curves
Lay cap units side by side with the short side facing out. In most circumstances, making two cuts on one cap and then not cutting the cap on either side produces the most pleasing look.
Corners
On a 90° corner wall, the corner caps need to be saw-cut to achieve a 45° mitered corner.
Stepping up caps
If a wall elevation changes, caps can be stacked where the wall steps up. Begin laying caps at the lowest elevation change and work your way back toward the previous step up. Split a cap unit to create a rough face on the exposed side. Place the half unit directly on top of the capped portion of the wall with all three split faces exposed.
Finishing
After layout is complete and caps are saw-cut or split to size, carefully glue with a concrete adhesive.
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| Drainage design |
- Each project is unique. The grades on your site will determine at what level to install the drain tile.
- 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. See Diagram 6.
- Fill in the area behind the blocks with drainage aggregate, at least 12 inches from the wall.
- You may need to place and backfill several courses to achieve the proper drainage level.
- Cover the drain tile with a geotextile sock which acts as a filter. The drain tile outlet pipes should be spaced not more than every 50 feet and at low points of the wall. In order for the drainage aggregate to function properly, it must keep clear of regular soil fill.
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| Reinforcement (if required) |
- Geosynthetic reinforcement is recommended for walls taller than 4 feet or walls situated in poor soils, supporting a driveway, for example. Consult a qualified engineer for design assistance.
- Check the wall construction plan for which courses will need reinforcement.
- Clean any debris off the top layer of blocks.
- Measure and cut the reinforcement to the design length in the plans.
- If a block in a multiple-height system intercepts the reinforcement, cut the reinforcement and position it around the block so that the reinforcement lies flat. To ensure reinforcement integrity, place grid on the horizontal plane that requires cutting around as few blocks as possible.
- The reinforcement has a design strength direction, which must be laid perpendicular to the wall.
- Place the front edge of the material on the top course, 2 inches from the face of the block.
- Apply the next course of blocks to secure it in place.
- To keep it from wrinkling, pull the reinforcement taut and pin the back edge in place with stakes or staples.
- Add drainage aggregate behind the blocks, then add the soil and compact it. See Diagrams 7 and 8.
- Remember — place the front edge of the reinforcement on top of the block, making sure it’s within 2 inches of the face of the block. Correct placement ensures that you maximize the connection strength and keep the batter consistent.
- A minimum of 6 inches of backfill is required prior to operating vehicles on the reinforcement. Avoid sudden turning or braking. See Diagram 8.
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| Compaction |
- Shovel the backfill soil behind the drainage aggregate and compact with a hand-operated compactor.
- Make sure the aggregate is level with or slightly below the top of the base course.
- Place soil in front of the base course and compact. Base course should be buried.
- Continue to fill and compact. See Diagram 8.
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| Finish grade and surface drainage |
- Protect the wall with a finished grade at the top and bottom.
- To ensure proper drainage away from the wall, use 6 inches of soil with low permeability. This will minimize water seeping into the soil and drainage aggregate behind the wall.
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| Site cleaning and restoration |
- Brush off the wall and pick up any debris left from the construction process.
- Notify the job superintendent in writing of the project’s completion and that it is ready for final inspection and acceptance.
- Planting vegetation in front and on top of the wall will help reduce the chance of erosion.
- Following these Best Practices for construction will ensure the successful installation of Anchor™ products.
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| Installation for optional Anchor™ Highland Stone® jumper unit |
- Install jumper units on top of an 18-inch-wide Highland Stone® unit.
- Set the jumper unit approximately 1 inch back from the face of the 18-inch-wide block on the lower course.
- Apply a concrete adhesive to secure the jumper unit.
- Place an 18-inch-wide Highland Stone unit on top of the jumper unit.
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| Placement |
- There is no required pattern for the Highland Stone jumper unit. You can achieve different looks by increasing or decreasing the number of jumper units.
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SAFETY NOTE: Always use appropriate equipment, including safety glasses or goggles and respirators, when splitting, cutting or hammering units.
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