Retaining Walls

A poured wall is one solid piece of reinforced concrete, formed and poured on a footing. It handles the most soil pressure per inch of thickness, takes a clean smooth or board-formed finish, and is the right call for taller walls, walls that hold up a driveway or a slab, and anything an engineer has to sign off on.

A CMU block wall goes on the same kind of footing, with vertical rebar dropped through the cells and the cells grouted solid. It costs less for short walls and goes up faster on a tight lot, and for a 2 to 4 foot garden wall or terrace it is usually the better value. Either way the footing, the steel and the drainage are built the same. The wall you see is the part that matters least.

Soil by itself pushes on a wall. Wet soil pushes much harder, and saturated DFW clay swells on top of that. A wall with no way to shed water is holding back a hillside plus a column of water, and that is the load that tips walls over or cracks them through the middle.

Behind every wall we build there is at least a foot of clean gravel with a perforated drain pipe at the bottom, wrapped in filter fabric and sloped to daylight, plus weep holes through the face as a second way out. We waterproof the back of the wall and grade the backfill so surface water runs away from it. Skip any one of these and the wall is fine the first dry summer and in trouble the first wet spring.

Tarrant County clay moves the most in the top couple of feet, where moisture changes season to season, and a wall sitting in that zone moves with it. We dig the footing below the active zone, wide enough to resist overturning, and key the wall into it with steel so the wall and footing act as one piece.

Footing size is set by wall height and what is behind it; on taller or surcharged walls the engineer sets it and we build to the drawings. Backfill gets compacted in lifts, not dumped in one pass, and heavy equipment stays off it until the wall has cured. The same ground movement is why most concrete cracks in North Texas — a wall is just a slab standing on its edge.

The residential code exempts retaining walls up to 4 feet tall, measured from the bottom of the footing to the top of the wall, as long as nothing surcharges them. That measurement is the one people miss: a wall showing 3 feet above grade on an 18-inch footing is a 4.5 foot wall to the inspector. A surcharge — a driveway, a pool, a building, a solid fence or another wall terraced above — needs a permit at any height.

Arlington's building code goes further: any wall over 4 feet of developed height, or with permanent construction closer to it than one and a half times its height, has to be designed by a Texas licensed engineer. Retaining walls also cannot go in a drainage, utility or right-of-way easement without an easement use agreement, and your lot's setbacks still hold. Confirm with the City of Arlington One Start Development Center, 101 W. Abram St, 817-459-6502; our permit FAQ covers how the process works.

Walls are priced per linear foot and height drives almost everything, because a taller wall needs a bigger footing, more steel, more gravel and more excavation. As a DFW market guide, CMU block up to 4 feet runs from the mid $20s to about $60 per linear foot installed and poured concrete about $30 to $60; over 4 feet, engineered or surcharged walls commonly run $60 to $150 or more. Tear-out, a stone or stucco face and difficult access add to that, and our job minimum is $1,800.

Tell us the length, the height you need to hold and what sits behind it, and we will give you a real number. If a railing or fence goes on top we set the wall up for it from the start with sleeves or embeds, and CJM Metals, our sister shop, builds and installs the steel.