Tools
The following tools will be helpful in building your VERSA-LOK Mosaic retaining wall system:
- The Mosaic system uses VERSA-LOK Standard, Cobble, and Accent units. The VERSA-Lifter is a tool that makes it easy to lift and place VERSA-LOK Standard units—especially on the base course.
- A 4-foot level will help keep your units level lengthwise, and a smaller torpedo level is helpful to keep them level front to back.
- A stringline stretched behind your wall will help you maintain a straight wall.
- A finishing trowel will help ensure a smooth, even layer of sand on top of your leveling pad.
- You will also need a shovel, tape measure, broom and some good gloves. Steel-toed boots are recommended any time you work with concrete.
- Although a hand tamper may be sufficient for compacting small jobs, a vibratory plate compacter will ensure that your crushed-rock leveling pad, drainage aggregate and backfill are compacted thoroughly and evenly.
- A large mallet is good to use for tapping units into place. A brick hammer can be used to modify the texture and to set your pins.
For splitting units while maintaining a split-face texture, such as for corners, you will need a masonry chisel and a 4-pound sledge hammer. If you plan to do a lot of splitting, consider renting a mechanical splitter.- If you’re going to be cutting any VERSA-LOK units where you need a smooth edge for tight-fitting joints, you should rent a gas-powered concrete cut-off saw with a diamond blade. You also can use a standard circular saw equipped with a masonry or diamond blade.
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Materials
The following materials are essential to ensure proper performance of your VERSA-LOK Mosaic wall:
- For your leveling pad, you will need a crushed-rock base material. Typically, this is the same material used for road base aggregate. You will top the leveling pad with a layer of sand.
- For drainage behind your wall, you will need three-quarter-inch clear, free-draining angular gravel aggregate.
- You will also need a supply of clean soil for backfill. This might be available from your excavation.
- Depending on the height of your wall, you may need a perforated, minimum 4-inch-diameter drain pipe to collect water along the base of the drainage aggregate and quickly move it away from the wall.
- You will need VERSA-LOK Concrete Adhesive and a caulking gun to bond your cap units to the top of the wall and to bond partial units that can't be pinned.
- Depending on how much your wall needs to support, you may need some VERSA-Grid geogrid soil reinforcement, a utility knife and stakes.
Preparation
Ground preparation is a critical step to ensure the performance of your wall.
To prepare the site for installation, you will need to excavate a 24-inch-wide trench deep enough to accommodate a 6-inch crushed-rock leveling pad, plus the embedded below-grade courses.
If the grade in front of the wall is level, one-tenth of the exposed wall height should be embedded below grade. When special conditions exist, such as slopes in front of walls, shorelines or soft foundation soils, additional embedded courses may be required.
Once your trench is excavated, compact the soil at the bottom. Properly compacted soils are critical to the performance of any VERSA-LOK retaining wall. A hand tamper can be used. But for best results, use a vibratory-plate compactor.
VERSA-LOK segmental retaining walls are installed on a 6-inch leveling pad of compacted crushed-rock base material topped with a half-inch layer of sand. Typically, the leveling pad is the same material that is used for road base aggregate.
Place and compact the crushed rock in the trench to a depth of 5.5 inches. If you’re using a hand tamper, compact the crushed rock in layers no more than 2 inches thick.
For final leveling, add a half-inch layer of sand on top of the leveling pad. You want to make sure that the leveling pad is level—front to back and side to side.