Why Patios Sink, Crack or Hold Water (And How to Fix It)
A practical guide for Chichester & West Sussex homeowners
If your patio is sinking, cracking, or holding water after rain, it’s a clear sign something isn’t right beneath the surface. These issues are extremely common in gardens across Chichester and surrounding areas — especially where patios were installed without proper groundwork.
In this guide, we explain why patios fail, the most common causes locally, and how to fix patio problems properly, not just cosmetically.
Common Patio Problems Homeowners Experience
You may have an underlying issue if your patio:
Has slabs that rock or feel loose
Has areas that have sunk or dipped
Cracks repeatedly
Holds puddles after rain
Slopes toward the house
Has joints washing out or filling with algae
These problems rarely fix themselves — and patch repairs often only delay the inevitable.
1️⃣ Poor or Insufficient Sub-Base
The most common cause of patio failure is an inadequate sub-base.
Problems include:
Sub-base that’s too thin
Poorly compacted hardcore
Incorrect material used
Sub-base laid directly onto soft ground
Without a solid foundation, slabs will inevitably move, sink, or crack.
2️⃣ Inadequate Drainage Beneath the Patio
In many West Sussex gardens, water struggles to drain away naturally.
Common drainage issues include:
Clay or compacted soil
No fall built into the patio
No escape route for water
Patio acting like a sealed surface
When water sits beneath slabs, it weakens the base and causes movement over time.
3️⃣ Incorrect Falls (Slopes)
Patios must be laid with a slight fall to allow surface water to run away.
Common mistakes:
Patio laid too flat
Fall running toward the house
Inconsistent slopes across the surface
Even a small fall error can result in persistent standing water.
4️⃣ Poor Bedding or Jointing Materials
Slabs need to be bedded correctly to support their full surface area.
Issues include:
Spot bedding instead of full bedding
Incorrect mortar mixes
Weak or failing joints
Jointing that allows water ingress
Once water gets in, freeze-thaw cycles and movement accelerate damage.
5️⃣ Ground Movement & Settlement
Ground naturally settles over time — especially where:
Soil was recently disturbed
Old patios were removed without recompaction
Heavy loads are placed on the surface
Without proper preparation, this settlement leads to uneven patios.
Can You Just Re-Lay or Replace Individual Slabs?
Sometimes — but not always.
Re-laying slabs may work if:
The issue is very localised
The base is otherwise sound
Drainage is adequate
However, repeated failures usually mean:
👉 The problem is structural, not cosmetic.
The Correct Way to Fix a Failing Patio
A proper fix usually involves:
Lifting affected areas (or the entire patio)
Assessing ground conditions
Improving drainage if required
Rebuilding the sub-base
Re-laying with correct falls and bedding
This approach costs more upfront — but prevents repeat issues.
Why Patios Commonly Fail in Chichester Gardens
Across West Sussex, we often see:
Heavy or mixed soil conditions
Older patios built to outdated standards
Patios installed without drainage consideration
Gardens altered over time without adjusting levels
Local experience matters when diagnosing and fixing these problems.
How Long Should a Properly Built Patio Last?
When installed correctly, a patio should last 20–30 years or more.
Longevity depends on:
Ground preparation
Drainage design
Installation quality
Material choice
A well-built patio shouldn’t need constant repairs.
Professional Assessment Makes the Difference
Patio problems can look simple — but the cause is often hidden below ground.
Professional assessment helps:
Identify the true cause
Avoid unnecessary work
Prevent repeat failures
Ensure long-term performance
Fixing it once, properly, is always cheaper than fixing it repeatedly.
Patio Repairs & Rebuilds in Chichester & West Sussex
If your patio is sinking, cracking, or holding water, addressing the underlying issue will restore both appearance and usability.
A properly rebuilt patio:
Drains correctly
Stays level
Looks better
Lasts far longer
If you are looking for a landscape Contractor in the Chichester area or the surrounding villages such as Bosham, Emsworth, Fishbourne, Itchenor, Witterings or Southbourne, then visit our patio installation service page to see examples of our work, and get in touch to get a free quote.
