Retaining wall installation
Turn a slope into usable yard, hold back a cut for a driveway or pool, or handle the grade change between your lot and the next.
A retaining wall holds soil at two different levels. In Washington County, retaining walls level hillside lots, hold the grade change between neighboring yards in new subdivisions, and make room for pools, RV pads and driveways. Most residential retaining walls here are reinforced concrete block, often with a privacy wall on top, though poured concrete, segmental block and rock walls are used too.
What makes a retaining wall different from a block fence?
A retaining wall is loaded from one side all the time. The soil behind it pushes on it, and that push gets much stronger when the soil is wet from a storm or a leaking sprinkler line. That's why retaining walls need a wider footing, more steel and grout, and drainage behind them. A privacy wall built on top of a retaining wall adds height and wind load, so the whole thing needs to be designed together.
When does a retaining wall need engineering and a permit?
In the City of St. George, retaining walls 4 feet or taller need a permit unless they're shown on an approved site plan, and the application has to include a drainage plan. For block and concrete walls, height is measured from the top of the footing. Walls holding up a driveway, pool, RV pad or building usually need engineering regardless. Ask your builder who provides the engineering and who pulls the permit.
What goes wrong with poorly built retaining walls?
- Hollow block with no rebar or grout, used to retain soil
- An undersized footing, or a footing poured on loose fill
- No weep holes, gravel or drain pipe behind the wall
- Sprinklers or drip lines soaking the soil right behind the wall
- Storm runoff pouring over the top of the wall
Each of these can look fine for a while, then show up as leaning, cracking or a bulge after a heavy monsoon storm.
What affects the cost of a retaining wall?
- Wall face area. Height times length is the starting point.
- Construction type. Reinforced block, poured concrete, segmental block or rock.
- Footing and steel. Taller walls need bigger footings and more reinforcement.
- Drainage. Gravel, pipe and an outlet.
- Access and excavation. Tight backyards and hard ground take longer.
- Engineering and permits. Needed for walls 4 feet and up or walls carrying a load.
Prices come from the builder after they've seen the site. We don't quote prices ourselves, and a phone estimate is only a starting point for a wall.
Where we connect you with help
Common questions
How is retaining wall height measured in St. George?
For concrete and block walls, from the top of the footing to the top of the wall. For rockery and segmental block walls, from the exposed face to the finished grade at the base.
Can I put a privacy wall on top of a retaining wall?
Yes, it's common in St. George, but the retaining wall has to be designed for the extra height and wind load. Tell the builder up front.
How long does a retaining wall take to build?
Short residential walls can take a few days. Engineered walls, permits and longer runs take longer. Your builder can give you a schedule after seeing the site.
Related services
- Block walls & privacy walls
- Wall repair & replacement
- Wall drainage & runoff fixes
- Terraces, pool & RV pad walls
More background: St. George retaining wall and block wall guide.
Block wall leaning or cracking?
A wall that's moving can fall without much warning. Keep kids, pets and cars clear and call to get it looked at.