Experts in Concrete Patio diagnostics and repairs

Why Your Patio Feels Bouncy or Hollow Underfoot

A patio should feel solid, stable, and secure when you walk across it. If it feels spongy, sounds hollow, or shifts slightly under pressure, there’s likely an issue hiding below the surface.

In this guide, we’ll explain what causes this bouncy or hollow sensation, why it’s more than just a nuisance, and how to fix it safely, before more serious problems like cracking or subsidence appear.

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Common Reasons for a Hollow or Bouncy Patio

Whether it’s paved or poured, a concrete patio should feel firm. When it doesn’t, the cause usually lies in the base, the slab, or the way the patio was installed.

Poor Sub-base Compaction

The most common cause is a sub-base that wasn’t properly compacted during installation. If the ground beneath your patio is loose or uneven, the slabs or slab above can flex underfoot, producing that hollow sound or springy sensation. Over time, this movement can widen joints, crack the surface, and cause sections to sink. Fixing it involves lifting the surface and rebuilding the base with MOT Type 1 or compacted sharp sand.

Poor Adhesion or Delamination

In tiled or overlay patios, the top layer may not have bonded correctly to the concrete beneath it. This is known as delamination and is often caused by moisture contamination, dust, or incorrect adhesive use. It results in air pockets that create a drum-like, hollow noise when tapped. Resurfacing or relaying may be required, along with surface preparation and proper adhesive selection.

Undermining from Water or Erosion

If water consistently drains beneath one section of your patio, particularly in corners or near gutters, it can erode the ground and create voids below the slab. This lack of support leads to movement when stepped on, and can rapidly worsen over time. In these cases, drainage correction and sub-base reinforcement are key to stabilising the area before relaying the surface.

Best Fixes for Loose or Unstable Patios

Lift and Relay Loose Slabs

Use slab lifters or chisels to remove bouncy or hollow-sounding pavers.
Inspect and level the bedding layer beneath, compact if needed with fresh mortar or sand.
Relay slabs firmly, ensuring full contact with bedding to avoid future gaps or bounce.

Foam Injection for Void Filling

If the issue is beneath a solid slab, polyurethane foam injection can fill hidden voids and re-stabilise the surface.
It’s fast-curing, non-invasive, and lifts from beneath without disturbing surrounding areas.
Often used in professional patio repairs where base erosion is the main issue.

Full Removal and Rebuild (If Widespread)

If the entire patio is unstable or improperly built, a full removal and reinstallation is usually best.
This ensures a compacted sub-base, proper drainage, and reinforcement as needed.
Gives peace of mind and prevents recurring issues for the long term.

Frequently Asked Questions

It can be. A patio that moves underfoot may cause trips or slips, especially in wet conditions. Over time, it also weakens joints and leads to cracks or sinking.

Filling visible gaps may offer temporary relief, but it doesn’t solve the underlying support issue. The base must be stable and compacted to provide long-term fix.

Tapping the patio surface with a rubber mallet or hard object will reveal hollow sounds. These areas often indicate voids or poor bonding underneath.

Yes, it’s a proven method for stabilising slabs. The foam is water-resistant and durable, expanding to fill voids without damaging surrounding surfaces.

We do. Our team offers free site assessments across the UK to identify underlying problems with your patio and recommend the most cost-effective repairs.