Why Your Pavers Are Sinking Behind Steps (And How to Stop the Slide)

The Scenario

A homeowner recently asked:

My brick walkway just recently started to sag in multiple spots... see where there are some gaps in the brick toward the edge of each step? Any idea what may be causing this?

The GardenOwl Diagnosis

The Assessment

You just bought your first house. You survive the moving trucks, unpack the boxes, and settle in for your first winter. Then, you walk out the front door after a snowstorm and nearly twist your ankle. Your beautiful brick walkway isn't just looking old; it's actively collapsing. Specifically, the bricks right behind the granite steps are sinking, creating ugly gaps and hazardous dips that destroy your home's curb appeal. It looks like the earth is swallowing your hardscape. If you are struggling with The Interlocking Friction Failure, you might be tempted to just pour a bag of sand in the hole and forget about it, but as a landscape architect, I'm telling you: don't. That is a temporary bandage on a structural wound.

The Trap: The "Water Dam" Effect

This isn't just about old bricks. This is a classic case of base failure caused by poor water management, exacerbated by the freeze-thaw cycle.

Here is what is happening underground: The granite riser (the vertical stone step) acts like a dam. When snow melts or rain falls, water runs down the slope and hits the back of that granite block. If the drainage isn't perfect, that water pools there and saturates the bedding sand under your bricks.

In the winter, that wet sand freezes and heaves (pushes up). When it thaws, it settles back down—but not evenly. Over time, the water washes the fine sand particles away, leaving a void. Your bricks have no support, so they sink. This is exactly why we warn against easy fixes on broken stairs—if the base is bad, the surface will fail.

The Solution: Excavate, Compact, and Lock

To fix this permanently, you have to treat the cause, not the symptom. You need a base that drains well and locks tight.

1. The Demolition

Carefully pull up the sunken bricks. Stack them aside; you can reuse them. You need to expose the base material underneath. You will likely find a pocket of loose, wet sand or just a hollow void behind the granite riser.

2. The "Sand Trap" Mistake

Do not just fill the hole with sand. Sand has no structural integrity on its own; it moves when water hits it. You need crushed stone (often called road base or crusher run). This material has jagged edges that lock together when compacted, creating a bridge that won't wash away.

3. The Geotextile Safety Net

Before you add your stone, I highly recommend laying down a piece of non-woven geotextile fabric in the hole. This acts like a filter. It allows water to drain through but stops your base material from migrating down into the subsoil. It is the best insurance policy against future sinking. (This is similar to the principle of preventing soil migration in trenches).

4. Compaction is King

Add your crushed stone in layers (lifts) of about 2 inches. Tamp it down hard. If you don't compact it, nature will do it for you later, and your bricks will sink again. You want that base to feel like concrete before you lay a single brick back down.

5. The Reset

Add a thin layer (1 inch max) of bedding sand on top of your compacted stone to level the surface. Re-lay your bricks. Use a rubber mallet to set them flush with the granite riser.

Pro Tip: For high-traffic steps, I often use a construction adhesive to glue the first row of pavers directly to the back of the granite riser (if the surfaces are clean and dry). This prevents them from drifting backward over time.

Visualizing the Result

Fixing hardscape is heavy, sweaty work. Before you start ripping up your front path, it helps to know what the finish line looks like. Are you just repairing the dip, or is this an opportunity to widen the path or change the brick pattern?

Using GardenDream, you can upload a photo of your current "disaster zone" and visualize it fully repaired—or even redesigned. It acts as a blueprint to ensure your labor is going toward a look you actually love.

If you want to test this on your own yard, upload a photo and see what this design would look like in your space using our Exterior Design App.