A retaining wall looks like landscaping, but it is a structure holding back thousands of pounds of soil and water. Strut E&I is a licensed retaining wall engineer for homeowners, builders, and property owners across the Southeast. We design new walls that stay put and assess walls that have started to lean, bulge, or crack.
A Retaining Wall Is a Structure, Not a Garden Feature
Soil pushes. The taller the wall, the harder it pushes, and that pressure grows quickly with height. Add water behind the wall and the load climbs again. Put a driveway, a parked car, a slope, or a house near the top and you have added more.
A wall that is not designed for those loads usually does not fail all at once. It tilts a little each wet season. Blocks shift. A crack opens at a corner. Then one spring, after a week of heavy rain, a section rotates forward or slides off its base. By then the repair is often a full rebuild, and anything sitting on the soil above it may be at risk.
The Southeast makes this worse. Many lots in metro Atlanta, Middle Tennessee, and the Carolina Piedmont are carved out of slopes, and our rainfall is heavy and arrives in bursts. Clay-rich soils hold water and drain slowly. Those conditions are exactly why drainage and proper design matter so much for walls in this region.
When a Retaining Wall Needs an Engineer
Requirements vary by jurisdiction, so always confirm with your local building department. As a general pattern, engineering is commonly required or strongly advised when:
Situation
Why it matters
The wall is taller than about 4 feet, measured from the bottom of the footing
Many jurisdictions use a threshold around this height for permits and sealed design
Anything is loading the soil above the wall (driveway, parking, pool, building, steep slope)
Surcharge loads add pressure the wall must resist
The wall supports a structure or a public way
Failure consequences are serious, and review is stricter
Walls are tiered or stepped close together
Upper walls load the lower ones
The site has poor drainage, soft soils, or prior movement
Water pressure is a leading cause of wall failure
An existing wall is leaning, bulging, or cracking
You need a diagnosis before choosing a repair
Even a shorter wall can need engineering if it carries a surcharge. A 3-foot wall with a driveway at the top is a different structure than a 3-foot wall with a flower bed behind it.
New Retaining Wall Design
We design walls to fit the site, the loads, and the budget, and we tell you plainly which wall type makes sense.
Segmental Block Walls
Interlocking concrete block walls are common on residential sites. Short gravity walls rely on the weight and batter of the block. Taller walls typically need layers of geogrid reinforcement extending back into the soil. We specify block type, setback, grid length and spacing, base and leveling pad, and drainage aggregate.
CMU and Cast-in-Place Concrete Walls
Reinforced concrete masonry and cast-in-place concrete cantilever walls work well where space behind the wall is tight, where the wall is also part of a building or garage, or where loads are high. We design the stem, footing, reinforcement, and the details that tie them together.
Timber Walls and Their Limits
Treated timber walls can work for low, lightly loaded applications. They have a shorter service life than masonry or concrete, and we are honest about where timber is and is not a good fit, especially for taller walls or walls with any surcharge.
Drainage Design
Most retaining wall failures we see involve water. Every design includes a drainage strategy: free-draining aggregate behind the wall, a perforated drain at the base with a real outlet, and attention to where surface water goes above the wall. A wall designed without drainage is designed for a load it will eventually get.
Geotechnical Coordination
For taller walls, commercial sites, and walls on questionable soils, a geotechnical report gives us the soil parameters the design depends on. We coordinate with your geotechnical engineer or tell you when one is needed, so the soil assumptions in the design match the ground you actually have.
Assessing a Failing Retaining Wall
If you already have a wall that is moving, the first question is not "what will a new wall cost." It is "why is this wall failing, and how fast." We evaluate:
Leaning or rotation: whether the wall is tipping forward and whether that movement is active.
Bulging: localized outward movement, often a sign of water pressure or reinforcement problems.
Cracking and displaced units: in block, CMU, or concrete, and what the pattern says about the cause.
Drainage failure: clogged or missing drains, saturated backfill, and surface water directed toward the wall.
Surcharge and changes above the wall: a new driveway, pool, addition, or regrading that the wall was never designed for.
You get a written, sealed assessment explaining what is happening and what the options are. Sometimes that is drainage correction and monitoring. Sometimes it is partial rebuild or reinforcement. Sometimes the wall has to come out. If a failing wall threatens a home, a foundation, or a neighbor's property, we will tell you that directly.
Call or Send Photos: Tell us about the site, the wall height, and what sits above it.
Site Visit: A licensed structural engineer evaluates the grade, soils, drainage, loads, and any existing wall.
Recommendation: We explain the wall type or repair approach that fits your site and why.
Design and Sealed Drawings: Calculations, details, and permit-ready drawings your contractor can build from.
Construction Support: We answer contractor questions and can review critical steps like base preparation and drainage.
Why Strut E&I
Strut Engineering & Investment, Inc. is a licensed structural engineering firm founded by Emad Badiee, who holds a BS and MS in Civil-Structural Engineering, has more than 16 years of experience, and is licensed in 28 states and the District of Columbia. Every project is assigned a dedicated licensed structural engineer.
Our forensic engineering work means we spend a lot of time studying structures that failed, including retaining walls, and that shapes how we design new ones. Our Director of Construction is a licensed General Contractor in Georgia, so our drawings are written to be built.
We serve homeowners, builders, developers, and property managers across Greater Atlanta, Nashville, Charlotte, and the rest of Georgia, Tennessee, the Carolinas, Florida, and New Jersey. Clients rate us 5.0 stars on Google, and they consistently mention the same things: thorough, responsive, and knowledgeable.
Frequently Asked Questions
Do I need an engineer for my retaining wall?
It depends on height, loads, and your local rules. Many jurisdictions require a permit and sealed design once a wall exceeds roughly 4 feet measured from the bottom of the footing, or when the wall supports a surcharge such as a driveway, slope, or structure. Check with your building department, and when in doubt, have an engineer look at it before you build.
Do I need a permit to build a retaining wall?
Often yes for taller walls or walls that support structures or slopes, and frequently not for short garden walls. The thresholds vary by city and county across Georgia, Tennessee, and the Carolinas. When a permit is required, the application usually needs sealed engineering drawings, which we provide.
Why is my retaining wall leaning?
The most common causes are water pressure from poor drainage, a wall that was undersized for its height or loads, inadequate geogrid reinforcement, a weak base, or new loads added above the wall after it was built. An engineering assessment identifies which of these is driving the movement so the repair addresses the cause.
Can a failing retaining wall be repaired, or does it have to be rebuilt?
Sometimes it can be repaired by correcting drainage, adding anchors or reinforcement, or rebuilding a section. Walls that have rotated significantly or lost their base usually need replacement. A sealed assessment tells you which situation you are in before you spend money on the wrong fix.
What type of retaining wall is best?
There is no single best type. Segmental block walls are cost-effective for many residential sites, reinforced concrete or CMU fits tight spaces and high loads, and timber suits low, lightly loaded walls. The right choice depends on height, space behind the wall, surcharge, soils, and appearance.
Do you work with geotechnical engineers?
Yes. For taller walls, commercial projects, and difficult soils, we coordinate with a geotechnical engineer so the design uses real soil parameters. If your project needs a geotechnical report, we will tell you early.
Talk to a Retaining Wall Engineer
Whether you are planning a new wall or watching an old one lean a little more each season, get a licensed engineer's answer before you build or repair.
