A retaining wall holds back a lot of weight, and what's behind and under it matters as much as the wall itself. We dig the footing, build the base, set the wall and install drainage so it stays put.
Retaining Wall Construction in Boise and the Treasure Valley
Retaining walls solve a few common problems. They hold back a slope above a house, level a backyard that tilts, make room for a driveway or shop and turn a steep bank into planting beds. Around Boise, they show up on foothills lots, hillside subdivisions in Eagle and Meridian, and on acreage in Star and Kuna where a pad has to be cut into a rise.
We build stone block retaining walls for homeowners and builders in Boise, Eagle, Meridian, Nampa, Caldwell and the surrounding area. One customer had us put in a stone block retaining wall and drainage around their home and said we were timely, professional and paid attention to all the small details.
Why Walls Fail
Most failed walls fail from the bottom or the back. A wall set on soft soil settles and tilts. A wall with no drainage behind it fills with water that pushes on it every spring, and wet clay is heavy. A wall backfilled in one big pile instead of compacted layers leans out over time. The block itself is rarely the problem.
That's why most of our work on a wall happens before and after the blocks go in: the dig, the base and the drainage.
Excavation and Footing
We start by cutting the slope back or digging the trench where the wall will sit, to the depth and length the plan calls for. The bottom of the trench has to be dug down to firm, undisturbed soil. Any soft or organic soil gets removed and replaced with compacted base. The first course of block is buried below grade, which gives the wall something to lean on.
The Base Course
The base is crushed rock, spread and compacted in layers until it's firm and level. This is the part you won't see, and it's the part that decides if the wall stays straight. The first course of block is set level, since each course above it follows the one below. A small error at the bottom gets bigger as the wall goes up.
Drainage Behind the Wall
Water is the biggest threat to a retaining wall. We build a drainage zone behind the wall with washed rock and, in most cases, a perforated drain pipe at the bottom that carries water out to daylight or a safe outlet. A fabric layer keeps soil from clogging the rock. For help with water problems on the rest of the lot, see our French drain installation and drainage solutions pages.
Backfill in Layers
As the wall goes up, we backfill behind it a layer at a time and compact each one. Doing it all at once creates soft spots that settle and push on the wall. Geogrid, a plastic mesh laid between layers, is used on taller walls to tie the soil behind the wall to the block. It's called for in the wall's plans when it's needed.
Wall Height, Plans and Permits
Short garden walls are simple. Tall walls, walls that hold up a driveway, a building or a slope, and walls with a slope or load above them usually need an engineer's design, and many cities and counties require a permit once a wall passes a certain height, often around four feet. Rules vary, so check with your city or county before you start. If your wall has an engineered plan, we build to it.
Know where the property line is before you build near it. A wall on or near a boundary can cause trouble with neighbors, and easements for utilities or ditches can limit where it goes. Digline (811) marks buried lines before we dig.
Walls and the Rest of the Lot
A retaining wall often comes with other earthwork. We can cut the slope, move the dirt from the cut, grade the area above and below the wall and haul away extra soil. See our excavation and grading and landscape contouring pages. Soil that was cut for the wall often gets reused as backfill or to level the upper area.
Why Call Ultimate Excavation LLC
We're an Idaho registered contractor (RCE-65836) based in Caldwell, with a 5.0 rating on Google. Our reviews say we're on time and pay attention to detail, which is what a wall needs. Tell us how tall the wall needs to be, how long it runs and what's above it, and we can get an estimate started. Call (208) 697-2429 or request a free estimate.
