Retaining Walls in Saskatoon

A retaining wall begins below ground. We excavate a trench, install and compact a granular base, and set the first course level and partly buried — the buried course is what anchors the wall, and a wall built directly on grade has nothing holding its base in place.

Each subsequent course is set back slightly so the wall leans into the slope it is holding. Behind the blocks we install free-draining granular backfill and a drainage path that takes water away rather than letting it collect. On taller walls, geogrid is laid back into the retained soil at intervals so the wall and the earth behind it act as one mass.

The wall is finished with capping units and the grade above and below is shaped so surface water is directed away rather than over the top. On Saskatoon clay, which sheds water rather than absorbing it, where the surface water goes is a design decision rather than an afterthought.

The most common reason in Saskatoon is turning an unusable slope into usable yard. A back yard that falls away steeply is space you cannot put a table on, and terracing it with a wall converts it into flat, usable ground. This is most of what we build.

The second is erosion and soil movement. A slope that is losing material every spring melt, dropping soil onto a patio or driveway, or pushing against a fence, is a slope that needs holding. Left alone it keeps moving, and it moves toward whatever is downhill.

The third is protecting a structure. Soil bearing against a foundation, a garage pad, or a driveway edge creates pressure and drainage problems, and a properly drained wall relieves both. Walls in older Saskatoon riverbank neighbourhoods are frequently doing exactly this job.

Water is behind almost every retaining wall failure here. Saskatoon clay holds water rather than draining it, and saturated soil is dramatically heavier than dry soil while also exerting hydrostatic pressure directly against the back of the wall. A wall built without drainage behind it is being asked to hold a load it was never designed for, every spring.

Frost compounds it. Water held in the soil behind an undrained wall freezes and expands, pushing the wall outward. Because that happens every year, the movement is cumulative — a wall that leans slightly after three winters leans noticeably after eight. Bulging in the middle courses is the classic signature.

The third cause is building too tall without engineering. There is a height beyond which a gravity wall cannot hold its load without reinforcement, and in Saskatchewan walls above a certain height need engineered design and typically a permit. Walls that fail catastrophically are usually walls that were built a course or two higher than the method allowed.

Height is the dominant factor and it is not linear. A wall twice as tall costs far more than twice as much, because the loads increase sharply, the base gets deeper, geogrid reinforcement becomes necessary, and above a threshold engineered drawings and a permit are required.

Length adds material and labour in a straightforward way, but curves, corners, steps, and tiers all add cutting and layout time beyond the raw metre count.

Block selection matters. A basic retaining block and a large architectural unit or natural boulder wall are different price points, and boulder walls in particular need machine access to place stone that cannot be lifted by hand.

Site access and disposal are the practical multipliers. Retaining wall work generates a lot of excavated material, and on a Saskatoon lot where a machine cannot reach the work area, both the spoil out and the granular in move by hand. Drainage requirements — where the water actually goes once it is collected — can add real cost on a tight lot.

Regrading is the cheaper answer and the right one when the slope is gentle enough to be reshaped into something usable and there is somewhere for the material to go. If a yard falls away modestly, excavation and grading alone can often produce a usable, gently sloped lawn for far less than a wall.

A retaining wall is necessary when the grade change is too abrupt to smooth out, when there is no room to spread the slope because of a property line or a structure, or when you want genuinely flat usable space rather than a gentler slope. Once you need to hold soil vertically, there is no cheaper substitute.

For larger grade changes, tiering two lower walls is frequently better than one tall wall — lower walls avoid engineering thresholds, spread the load, and usually cost less than a single structure of the same total height. The right choice depends on how much horizontal room you have, which is what we work out on site.