Excavate and Prepare Foundation Trench

What happens in this clip

After marking the wall's footprint, begin digging the trench for the first course of timbers. The trench should be deep enough to accommodate both the timber and a layer of crushed stone beneath it. The video specifies digging down 6 inches for the timber and another 6 inches for the crushed stone, resulting in a total depth of 12 inches. Once the trench is excavated, thoroughly compact the soil at the bottom. Next, fill the trench with a 6-inch layer of 3/4-inch crushed stone. Spread this stone evenly and then compact it firmly using a tamper or plate compactor. This creates a stable and well-draining foundation for your retaining wall.

Goal: Create a stable and well-drained base for the first course of timbers.

What's used

Tools

• Shovel UnionTools
• Trenching shovel
• Tamper
• Wheelbarrow UnionTools

Materials

• 3/4-inch crushed stone

About the full video

This project provides a comprehensive guide on how to construct a timber retaining wall. It covers everything from initial site layout and foundation preparation to laying courses of pressure-treated timbers, ensuring proper drainage, and installing 'deadmen' anchors for structural integrity. The process emphasizes precision in measurement and leveling for a durable and aesthetically pleasing result.

Step 2 of 8: Excavate for First Step

Excavate the area marked for the first step. The depth should be sufficient to accommodate the timber depth plus a few inches for drainage and compaction. Create a level base for the timber to rest on. Dig a trench where the retaining timbers will be placed, ensuring they will be flush with or slightly below the final desired step height.

Open this step in the guide

Other videos for this step

• Dig Trench and Level First Base
• Excavate Terraces