One Tall Retaining Wall or Several Terraces?

Because the force behind a retaining wall grows much faster than the wall does, so a tall wall is a different structure, not a bigger version of a short one.

The soil behind a wall pushes outward, and that push increases with depth. Add height and you add both more soil and more pressure at the bottom of it, so the total load climbs steeply. Doubling the height of a wall roughly quadruples the load it has to resist. That is why a three-foot garden wall can be a gravity structure, relying on its own weight and a good footing, while a wall twice that height usually needs geogrid reinforcement layered back into compacted fill so the soil mass itself becomes part of the structure.

Water makes all of this worse. Saturated soil weighs more than dry soil and, if it cannot drain, it adds water pressure on top of earth pressure. The industry design guide for segmental walls, CMHA (formerly NCMA) SRW-TEC-004, starts from the principle that water should be directed away from the wall wherever possible and properly drained where it does reach it. A tall wall in a wet spring is carrying far more than it did in August.

This is the trade-off in one table, assuming the same total change in level.

One caution on the terrace column: terraces only reduce the load if they are spaced far enough apart. Stack low walls too close together and the upper wall bears on the lower one, and the pair behaves like a single tall wall without being designed as one.

In the two cities with the clearest published rules, the line is four feet.

Bentonville requires a retaining wall permit for any wall segment over four feet high, measured from the finished grade on the lower side to the top of the wall. It is applied for through the city's eTrakit portal with a signed application and a plot plan showing the wall, its distance to structures and its distance to property lines. Grading is a separate application.

Fayetteville requires a grading permit where a retaining wall is over four feet, where slopes are fifteen percent or steeper, in the Hillside/Hilltop Overlay District, or in the floodplain, and the grading plan has to be endorsed by an engineer or landscape architect licensed in Arkansas. On the steeper Fayetteville lots the slope rule can apply before the wall height does.

Rogers, Springdale and Bella Vista each run their own process, and in Bella Vista the POA's Architectural Control Committee reviews exterior changes separately from the city. Outside city limits in Benton County the rules differ again. All of this was checked September 2026; confirm with your city before you design around a height, or let us do it as part of the job. There is more detail in our permits guide.

The point for this decision is simple. Two three-foot terraces and one six-foot wall hold back the same change in level, and they are not the same project on paper.

Usable ground at more than one level, which on a sloped lot is usually what people actually wanted in the first place.

A dining terrace off the kitchen door, steps down to a fire pit, and a lower level flat enough for children or a dog. Each level becomes a room with its own purpose. One tall wall gives you a single plane at the bottom and a cliff behind it, which is fine if the goal is a big flat lawn and wasteful if the goal was somewhere to sit.

Terraces also soften the result. A tall wall reads as civil engineering, however good the block is. Low walls with planting in between read as garden, and the planting does real work: roots and mulch slow surface water on its way down and reduce erosion on each bench.

They are also more forgiving over time. If one tier needs attention after a hard winter, it is one tier. If a single tall wall starts to lean, the whole grade change is the problem.

When the slope is short and steep and there is no horizontal room to step it.

Terracing eats distance. Each level needs enough depth to be worth standing on, plus enough separation from the wall below that it is not loading it. On a tight lot with a steep bank close to the house, the arithmetic may simply not work, and then one properly engineered wall is the honest answer. The same is true when you need the maximum flat area in one place, for a pool, a sport court or a driveway turn.

If that is where you land, build it as the structure it is: a real footing, geogrid sized by a designer for that block and that height, backfill compacted in lifts, and drainage designed in. Do not accept a tall wall priced like a short one.

Drainage and a proper footing, at three feet and at eight.

SRW-TEC-004 calls for at least twelve inches of free-draining aggregate behind segmental wall units and a drain pipe of at least three inches diameter, and the pipe has to discharge somewhere deliberate. A pipe that goes nowhere fills up and does nothing. Behind every tier of a terrace, the same applies.

The ground adds its own requirement. On the Springfield Plateau, across Benton County, the Boone Formation is limestone and chert that the Arkansas Geological Survey describes as karst, so rock can turn up well above where the footing was drawn and water moves through fractures in ways a flat site plan does not show. From Fayetteville south, the Fayetteville shale swells when it wets and shrinks as it dries, which UA geologist Walter Manger identified as the root of the area's foundation problems. A wall footing on shale that is allowed to cycle between wet and dry will move. Excavate to competent ground and keep the water away from it.

If you already have a wall that is leaning, start with why retaining walls lean and why they fail.

Measure the total drop, measure the horizontal distance you have to lose it in, and decide what each level is for before anyone draws a wall.

The total drop tells you how much retaining the site needs in all. The horizontal distance tells you how many levels you can fit, because each usable terrace needs real depth: enough for a table and chairs with room to walk behind them, or enough for a lawn a child can actually run on. The purpose of each level sets that depth, and the depth sets how many tiers the slope can hold. Working the other way round, starting from a wall height someone likes the look of, is how people end up with narrow shelves nobody uses.

Then look at the constraints that do not show on a sketch. Where do the utilities run? Arkansas 811 has to be called before anyone digs, and a gas or power line across the slope can decide where a footing goes. Where does water arrive from, and where can it legally leave? A terrace scheme that sends every tier's drain line at a neighbour's fence is not a finished design. How does a machine get to the bottom of the slope? On the older Bentonville and Fayetteville lots, access alone can make a tall wall impractical because the equipment to build it cannot reach.

Finally, read the ground. On the plateau, test pits or an early look at the dig often find chert or rock shallower than expected, which can make a low terrace footing easy and a deep tall-wall footing expensive. On the shale further south, the question is how deep you have to go to reach ground that is not cycling, and how you keep water off it. Those answers shift the decision more than any rule of thumb does.

Terrace the slope if you have the horizontal room, because you get lower loads, a better chance of staying under the four-foot permit line, usable space at several levels, and a garden rather than a structure.

Build one tall engineered wall if the slope is short and steep, if you need one large flat area, or if the site simply cannot give each terrace enough depth. Budget for the engineering, the geogrid and the permit from the start rather than discovering them.

In both cases, drainage and the footing are the part that decides whether it is still straight in ten winters, and they are the part a cheap quote leaves out. Projects start around seven and a half thousand dollars, financing is available through Acorn Finance, and the right answer for your slope is a site visit question. Call Paco on (479) 379-2226.