How to Build an Interlocking Retaining Wall
Build a strong, stylish retaining wall without mortar. We'll show you how.
Interlocking concrete block is a way to build a strong wall without mortar. Some such blocks are made with flanges that slip over the rear edge of the preceding course; others rely on a system of pins. With both types, you don't have to practice throwing mortar or setting block, but you will get an attractive addition to your landscape. The flanges slope the wall back into the slope for additional strength.
Interlocking-block walls don't require a footing, but some styles require you to set the first course in a trench to hold the bottom of the wall in place. Cut the slope back 12 to 15 inches from the rear of the trench to leave room for gravel backfill and a drainpipe—a must for retaining walls. Save the topsoil and use any extra as fill elsewhere in your landscape.
To lay a 3x16-foot wall, expect to spend 10 to 20 hours. You'll need to feel comfortable digging, designing a layout, leveling, and laying brick. Before you begin, call your local hotline to mark any underground utilities.