Retaining walls and seat walls

Two different jobs that look the same

Retaining walls are structural. They hold grade, create usable flat space out of a slope, and manage where water goes. Seat walls are furniture - low walls that edge a patio, define the space and mean you are not hauling chairs out every time people come over. We build both, often on the same project, and they are engineered very differently.

What makes a retaining wall last

• A compacted base below frost consideration. The first course sets everything above it. If it is not dead level on compacted aggregate, the wall telegraphs that error all the way up.
• Drainage stone and drain tile behind the wall. This is the one most commonly skipped, and it is the one that causes failures. Saturated soil exerts dramatically more pressure than drained soil. A wall built without drainage is a wall on a countdown.
• Geogrid on taller walls. Layers of structural mesh tied back into the retained soil, turning the soil mass itself into part of the structure. Non-negotiable past a certain height.
• Proper backfill. Clean stone, not the clay that came out of the hole.
• Batter. Each course set slightly back into the hill, so the wall leans into the load rather than away from it.

Walls above four feet, or any wall carrying a surcharge like a driveway or a structure above it, need engineered drawings and usually a permit. We will tell you when you are in that territory rather than quietly building something that should have been engineered.

Where they earn their keep in Macomb County

Around Stony Creek and through Washington Township, rolling glacial terrain means half the yards worth landscaping need a wall before they need anything else. Along the lake in Harrison Township and St. Clair Shores it is the water table rather than the grade - high groundwater and wave-driven moisture make drainage design the whole job.

And in the flat postwar subdivisions further south, a seat wall is often the single best value in hardscape: it is not structural, it is not expensive, and it turns a rectangle of pavers into an outdoor room.