How to build a retaining wall on a slope?

1. Choose the type of wall you want to build. There are several types of retaining walls, including timber, concrete, stone, and rock.
2. Determine the size of wall you need. Make sure the size of the wall is appropriate for the slope and the amount of soil it needs to hold back.
3. Measure and mark the wall site. Clear out any trees and roots from the area, and use a level and string to mark the area where the wall will go.
4. Excavate the area and remove any topsoil. Dig to a depth of about 6 inches below the proposed finished height of the wall.
5. Compact the soil. Use a tamper or a heavy roller to compact soil and ensure the foundation is even and level.
6. Lay down a layer of gravel and an impermeable barrier. This will help with drainage and prevent groundwater seepage into the wall.
7. Assemble your materials. Use staggered layers of large rocks or stones, depending on the type of wall. For a concrete wall, you will need forms, rebar, concrete, and sealant.
8. Build the wall. If using stones or rocks, make sure each piece is resting squarely on the one beneath it, and that each layer is set back at least 6 inches from the one above for stability.
9. Install drainage and finish the wall. Install a drainpipe to allow water to flow away from the wall and fill in behind the wall with soil, tamp it down, and add topsoil if desired.