Retaining Wall Planning Checklist: Drainage, Permits, and Height Limits

A retaining wall holds back soil, so drainage, base preparation, and height limits matter more than appearance. Many local codes require permits and engineering for walls above a certain height, often around four feet measured from the bottom of the footing, or for walls supporting driveways, structures, or slopes. Check local rules before choosing materials.

Poorly built walls lean, crack, or collapse, which can damage property and create safety risks.

Planning Checklist

• Measure the wall height and length needed.
• Check permit and engineering requirements with your building department.
• Identify loads above the wall, such as driveways, fences, or buildings.
• Locate underground utilities by calling 811 before digging.
• Plan where water will drain.
• Choose materials suited to the height and load.

Drainage Is Everything

Water pressure behind a wall is a major cause of failure. Good walls include free-draining gravel behind the wall, a perforated drain pipe at the base, and outlets that carry water away. Without drainage, saturated soil pushes harder against the wall, especially after heavy rain or freeze-thaw cycles.

Ask contractors how they will handle drainage and where water will exit.

Materials and Construction

Common materials include segmental concrete blocks, natural stone, poured concrete, and timber. Segmental block walls often use geogrid reinforcement for taller walls. A compacted gravel base and buried first course help keep walls level and stable.

Timber walls may cost less upfront but usually have shorter lifespans. Ask about expected life and maintenance for each material.

Signs a Wall Needs Attention

Watch for leaning, bulging, cracks, gaps between blocks, soil washing out at the base, or water pooling behind the wall. These signs often mean drainage problems or structural stress. Small issues can sometimes be repaired, but leaning walls may need rebuilding.

Keep drains and outlets clear of debris, and avoid adding heavy loads, such as vehicles or new structures, near the top of a wall without checking its design limits.

Ask contractors how they will protect nearby landscaping and lawns during construction. Plan plantings above the wall carefully, since large tree roots can push against walls over time.

Hiring a Contractor

Request written quotes describing excavation, base depth, drainage, reinforcement, and backfill. Ask for photos of walls built several years ago, and confirm insurance and licensing.

Retaining wall and hardscape contractors are listed in Link Centre’s construction and remodeling pages, so property owners can compare several quotes.

Build It to Hold

Successful retaining walls depend on permits, engineering when required, strong bases, reinforcement, and above all, drainage. Call 811, choose suitable materials, and compare detailed quotes. Link Centre can help you find retaining wall contractors.