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Cracked or Heaving Brick Patio
in Nashville, TN
A brick patio heaves when the ground underneath it moves up, and it cracks when sections settle at different rates. Nashville's clay soil expands when it gets wet in spring and shrinks and cracks in a dry summer — and a brick patio sits right on top of all that movement. Tree roots are a common cause too, especially in older Nashville neighborhoods where mature trees are everywhere.
Quick Answer
Brick patios crack or heave when the ground underneath shifts. In Nashville, clay soil swells after rain and shrinks in dry summers, and that movement lifts and drops the bricks above it. Tree roots also get under patios and push bricks up. Raised bricks are a trip hazard, and the gaps they leave let more water in and make it worse faster. Having a mason look at the base before resetting bricks is worth it — otherwise you'll be fixing it again in a few years.
Telltale Signs
Warning Signs to Watch For
- Individual bricks raised above the surrounding surface, creating a bump
- Bricks that rock or wobble when you step on them
- Gaps between bricks where sand or base material has washed out
- Sections of patio that have dropped lower than the rest
- Cracks running across multiple bricks in a line
- Bricks near a tree that are pushed up unevenly from below
Root Causes
What Causes Cracked or Heaving Brick Patio?
Clay Soil Expansion and Contraction
Nashville's soil is heavy in clay, especially in older parts of town like Donelson and Hermitage. That clay swells when it absorbs the heavy spring rains and then dries and shrinks in summer heat. A brick patio laid directly on this soil rises and drops with it, eventually cracking and going out of level.
The Fix
Patio Reset with Compacted Gravel Base
Bricks are pulled up, the clay base is excavated and replaced with compacted crushed stone, and the bricks are relaid on top. Gravel doesn't swell and shrink the way clay does, so the patio stays stable.
Tree Root Intrusion
Tree roots grow toward moisture, and a brick patio often sits over moist soil in a shaded yard. Roots work their way under the patio and physically lift bricks as they grow thicker every year. This is common in Nashville yards with older oaks or maples within 20 feet of the patio.
The Fix
Root Removal and Brick Relay with Root Barrier
Affected bricks are removed, the root is cut back, and a root barrier is installed before the bricks are reset. The barrier redirects future root growth away from the patio.
Poor Original Sand Bed and Drainage
Brick patios are supposed to be laid on a packed sand bed over gravel so water drains down and away. Many patios in Nashville built in the 1980s and 1990s were laid on plain soil or thin sand with no drainage underneath. Rain washes the sand out from under the bricks, and sections drop into the voids.
The Fix
Full Patio Demo and Proper Base Installation
The old patio is taken up, a proper gravel and sand base is installed with adequate drainage slope, and the bricks are relaid level. This is the only way to stop the cycle of resetting bricks every few years.
Self-Diagnosis
Which Cause Applies to You?
Check the signs you're observing to narrow down the likely root cause before your inspection.
| What You're Seeing | Clay Soil Expansion and Contraction | Tree Root Intrusion | Poor Original Sand Bed and Drainage |
|---|---|---|---|
| Bricks rise and fall with the seasons, higher in spring and lower in late summer | |||
| Bricks pushed up in a fan or curve pattern near a tree trunk | |||
| Sand washing out from between bricks after heavy rain | |||
| Multiple sections sunken in different spots across the whole patio | |||
| Bricks heaving only in one corner near a large tree | |||
| Cracks and movement spread evenly across the whole patio surface |
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