Knott Mill, Manchester | System THX

LOCATION

Knott Mill, Manchester

WATERPROOF SYSTEM

System THX

Project Overview

A commercial office building experienced persistent water ingress due to an aging flat roof system. The client required a cost-effective refurbishment solution that avoided a full roof replacement while ensuring long-term waterproofing.

Objective

• Eliminate leaks and prevent future water ingress
• Extend the lifespan of the existing roof
• Avoid costly and disruptive roof removal
• Deliver a seamless, weather-resistant finish
• Complete works with minimal disruption to occupants.

 

Solution: PU Liquid Overlay System

A polyurethane (PU) liquid-applied waterproofing system was specified. This system creates a fully bonded, seamless membrane that can be applied directly over the prepared existing substrate, significantly reducing time and cost.

 

Scope of Work

1. Roof inspection and moisture assessment
2. Cleaning and preparation of existing surface
3. Localized repairs to damaged areas
4. Application of PU primer to enhance adhesion
5. Installation of reinforced PU liquid overlay system
6. Application of UV-stable topcoat

 

Challenges

• Substrate variability: Aged surface required careful preparation
• Drainage issues: Ponding areas needed correction before overlay application
• Access limitations: Work conducted in an occupied building

 

Implementation

The project was delivered in stages to ensure quality and efficiency:

• The roof was thoroughly cleaned and mechanically prepared
• Damaged sections were repaired and leveled to improve drainage
• A primer was applied to stabilize the substrate
• A reinforced PU liquid membrane was installed, embedding a fiberglass mat in high-risk areas
• A UV-resistant topcoat ensured long-term weather protection

 

Results

• Fully waterproof system: All leaks eliminated
• Seamless finish: No joints or weak points
• Improved drainage: Reduced standing water
• Extended lifespan: Roof life extended by 20years
• Minimal disruption: No need for full roof removal

 

Key Benefits

• Cold-applied system (no hot works required)
• High elasticity accommodates structural movement
• UV and weather resistant
• Suitable for complex roof details (penetrations, upstands, edges)
• Lightweight—no additional structural load

 

Conclusion

The PU liquid overlay system provided a reliable, efficient, and long-lasting solution for refurbishing the failing flat roof. By avoiding a full roof replacement, the client achieved substantial cost savings while significantly improving building protection and performance.

 

We worked closely with Crescent Roofing for this job. ‘Great product, great company, what more can you want!’ 

For more about our market leading liquid waterproofing solutions check out System THX or call our team on 0161 777 9009 to place your order.