What to Do: Leak on a Roof with Ballasted Rocks on Top?

Ballasted roofs — where gravel or stone covers a single-ply membrane — are among the most difficult roofing systems to diagnose and repair when leaks develop. Here's what to do.

Why Ballasted Roofs Are Hard to Fix

The gravel hides the membrane surface completely, making visual leak detection nearly impossible. Water can enter through a breach anywhere beneath the ballast, travel laterally along the membrane, and exit the ceiling 20–30 feet from the actual entry point. Traditional spot repair requires removing gravel from a large area, locating the breach, patching it, and re-spreading gravel — a labor-intensive process with no guarantee of finding all breaches.

Step 1: Infrared Scan

An infrared scan performed at dusk can identify wet insulation beneath the ballast by detecting heat signatures. This helps narrow the search area before any gravel is moved.

Step 2: Core Samples

Once wet areas are identified, core samples confirm moisture levels in the insulation below and help determine whether restoration or replacement is viable.

The Spray Foam Solution

For ballasted roofs at end of life, spray foam restoration after gravel removal is often the best solution. The gravel is hydro-vacuumed, the existing membrane substrate is inspected, wet insulation is replaced, and foam is applied creating a completely new seamless surface. This eliminates every existing breach simultaneously — no hunting required.