The image compares two patio installations and clearly shows why drainage is the deciding factor between a long-lasting surface and one that cracks, settles, and sinks.
What Goes Wrong Without Drainage
On the left side, the patio is built directly over soil with no path for water to escape.
- Rainwater seeps downward and saturates the soil
- The soil softens and shifts over time
- Pavers lose support and begin to crack or sink
- Freeze–thaw cycles make the damage worse
This is why patios without drainage often fail even if the surface looks well laid at first.
Why Drainage Makes the Difference
On the right side, a proper drainage system redirects water away from the patio base.
- A gravel sub-base allows water to move freely
- A drainage pipe or channel collects excess water
- Water is carried away instead of pooling underneath
- The base remains stable and compact
By keeping moisture under control, the patio stays level and structurally sound for years.
Key Elements of a Stable Patio Base
A correctly built patio typically includes:
- Compacted soil subgrade
- A thick gravel or crushed stone base
- Slight surface slope away from structures
- Drainage pipe, channel, or dry well where needed
These layers work together to prevent water pressure from undermining the surface.
When Drainage Is Especially Important
Proper drainage is critical if:
- Your soil is clay-heavy or poorly draining
- The patio is in a low or flat area
- Heavy rain is common in your climate
- The patio sits near a house foundation
Ignoring drainage in these conditions almost guarantees future sinking.
Takeaway
Patio sinking is rarely a surface problem—it’s a water problem.
A solid-looking patio without drainage is temporary. A patio with a well-designed drainage system is built to last.