Green Roof Waterproofing and Drainage, Gloucestershire - Case Study

The Client

A private client in Gloucestershire commissioned the design and installation of a high-performance green roof that would combine both hard and soft landscaping while maintaining long-term waterproof protection.

The Brief

The brief was to create a waterproof and well-drained roof surface capable of supporting vegetation, paving, and other landscaping elements. The system needed to provide reliable protection against water ingress while promoting controlled drainage and root resistance.

The Challenge

Green roofs require precise management of waterproofing, root protection, and drainage. The mixed use of hard and soft landscaping meant the system needed to support structural loading, manage excess rainwater effectively, and safeguard the substrate against moisture-related deterioration.

The Solution

A comprehensive two-part waterproofing and protection system was implemented to ensure long-term performance of the roof structure.

First, the substrate was treated with PermaSEAL PRO MP 2C, forming a flexible, fully bonded waterproof barrier that safeguarded the structure from water ingress. Once the waterproofing layer was complete, PermaSEAL PRO Root Barrier was installed to protect the roof from potential damage caused by plant and tree root penetration.

To complete the system, PermaSEAL PRO 8 Green Roof Drainage Membrane was laid above the root barrier. Its dimpled design provided a continuous, high-performance drainage layer, allowing excess water to flow freely beneath the landscaping build-up. This ensured the ideal balance between retaining essential moisture for plant growth and enabling rapid drainage during heavy rainfall.

Products Used

• PermaSEAL PRO 8 Green Roof Drainage Membrane – Provides reliable drainage and protection for green roofs. Its tough dimpled structure supports soil and vegetation while allowing efficient water run-off.
• PermaSEAL PRO MP 2C – A flexible, cementitious waterproof coating that creates a seamless and durable barrier against water ingress. Ideal for green roof and structural waterproofing applications.
• PermaSEAL PRO Root Barrier – A robust membrane designed to prevent plant and tree roots from penetrating and damaging the waterproofing layer, ensuring long-term protection of the roofing system.

Results

The completed roof delivers robust waterproofing and consistent drainage performance. The combination of the PermaSEAL PRO system ensures that both the hard and soft landscaped areas remain protected, stable, and visually appealing throughout seasonal weather changes.

Why This Matters

This project demonstrates how reliable waterproofing and drainage design can extend the lifespan of complex roof landscapes. With the PermaSEAL PRO system, the client benefits from long-term protection, easy maintenance, and enhanced performance across mixed-use roof areas.

Permagard – Providing Solutions. Inspiring Confidence.

Permagard supplies trade-trusted waterproofing and green roof systems with free technical advice and design support. With over 35 years of experience, we offer reliable delivery in 1–3 working days and proven systems for long-lasting performance. Call 0117 982 3282 or email [email protected] to discuss your next waterproofing project.