Case Study · Flat Roofing · Liverpool

Complete Flat Roof Replacement. Residential Property, Liverpool

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A detailed look at how we completely replaced a failing flat roof on a residential extension in Liverpool, transforming a leaking, perished roof into a modern, watertight GRP fibreglass system with a 25-year guarantee.

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The Challenge: A Failing Flat Roof Causing Ongoing Leaks

The customer contacted us after months of dealing with water ingress into their rear extension. The original felt flat roof, installed over 15 years ago, had reached the end of its lifespan and was causing significant problems throughout the property.

Multiple leaks appearing during and after heavy rainfall, causing water stains on the ceiling
Original felt membrane completely perished and lifting in multiple areas
Water pooling in the centre of the roof due to poor drainage and sagging deck
OSB deck showing signs of rot and deterioration from long-term water ingress
Flashings around the perimeter were failing, allowing water to track behind the fascia
Customer needed a permanent solution with a long-term guarantee

“We’d been putting up with leaks for months, especially during heavy rain. The old felt roof was completely perished and water was getting into the extension. Maintenance Free Roofing came out within 24 hours, gave us a clear quote, and completed the work in just 3 days. The new GRP roof looks fantastic and we haven’t had a single leak since—even through the storms we’ve had. Professional, tidy, and exactly what they promised. Highly recommend!”

— Sarah & James M., Allerton, Liverpool | October 2024

Our Solution: Complete Strip & GRP Fibreglass Replacement

After a thorough inspection, we recommended a complete strip-back and replacement with a premium GRP (Glass Reinforced Plastic) fibreglass system. This would provide a seamless, watertight finish with a 25-year guarantee and minimal maintenance requirements.

Complete removal of old felt membrane and damaged OSB deck
Installation of new 18mm OSB3 deck, properly secured and level
GRP fibreglass system: resin, chopped strand mat, and topcoat
New aluminium edge trims and upstands for clean, professional finish
Replacement of all flashings and sealants around perimeter
Gutter connection checked and improved for proper drainage
Full site cleanup and waste removal included
25-year written guarantee on materials and workmanship

Project Timeline: How We Completed It in 3 Days

We kept the customer informed at every stage, providing photo updates and clear communication throughout the project. Here’s how the work progressed:

Day 1: Strip & Preparation

Complete removal of old felt and damaged deck. Site protection installed. New OSB3 deck measured, cut and fitted. All flashings removed and areas prepared for new system.

Day 2: GRP Installation

Base resin layer applied. Chopped strand mat laid and rolled. Second resin coat applied. Edge trims and upstands fitted. System left to cure overnight.

Day 3: Finishing & Cleanup

Final topcoat applied for UV protection and finish. All flashings and sealants completed. Gutter connections checked. Full site cleanup and waste removal. Final inspection and handover.

Materials & Quality: What We Installed

We only use premium materials from trusted suppliers, ensuring long-term performance and reliability. Here’s what went into this installation:

GRP System

Premium Fibreglass

High-grade resin and chopped strand mat for seamless, durable finish.

Decking

18mm OSB3

Moisture-resistant oriented strand board, properly secured and level.

Edge Trims

Aluminium

Premium aluminium trims for clean edges and weather protection.

Flashings

Lead & Sealants

Professional leadwork and high-grade sealants for watertight junctions.

Guarantee

25 Years

Comprehensive written guarantee covering materials and workmanship.

Key Features & Benefits of This Installation

This GRP flat roof replacement delivers long-term value and peace of mind for the customer. Here’s what makes this installation special:

Seamless Waterproof Finish

No joints or seams means no weak points. Completely watertight system.

25-Year Guarantee

Comprehensive written guarantee covering both materials and workmanship.

Low Maintenance

GRP requires minimal maintenance, just occasional cleaning to remove debris.

UV Resistant

Topcoat provides protection against UV degradation and weather damage.

Professional Finish

Clean edges, neat trims, and seamless appearance enhance property value.

Improved Drainage

New deck properly levelled ensures water flows correctly to gutters.

Before & After: See The Transformation

These photos show the dramatic improvement from the old, failing roof to the new, watertight GRP system. The transformation speaks for itself.

Results: A Watertight Roof That Will Last Decades

This project delivered exactly what the customer needed: a permanent solution to their leaking roof with a long-term guarantee and professional finish. Here’s what was achieved:

Complete elimination of all leaks—no water ingress even during heavy storms
Modern, professional appearance that enhances the property's value
25-year written guarantee providing long-term peace of mind
Improved thermal performance with new deck and proper insulation considerations
Zero maintenance requirements—just occasional cleaning to remove debris
Customer delighted with the quality of work and professional service
Project completed on time and within the agreed budget

Why This Project Succeeded

This project demonstrates our approach to flat roof replacement: thorough inspection, clear communication, quality materials, and professional installation. Here’s what made the difference: