Flat Roof Waterproofing Systems
A guide to the main flat roof waterproofing systems available for residential and commercial projects — including EPDM rubber roofing, liquid rubber, spray-grade coatings and specialist membranes.
What system should you use?
The right flat roof waterproofing system depends on your project scale, substrate and application type. For projects in the North West — serving Blackburn, Preston and Manchester — these are the most commonly specified systems:
EPDM Rubber Roofing
Sheet membrane for residential flat roofs. Garden rooms, extensions, garages. Up to ~300m².
View EPDMLiquid Rubber HBS200
Cold-applied brush/roller system for roof repairs, gutters, joints, complex areas and refurbishment.
View Liquid RubberSprayGrade
Spray-applied liquid rubber for warehouses, factories and large commercial roofs. Approximately 600m² per day under suitable conditions.
View SprayGradeChoosing the right flat roof waterproofing system depends on the type of structure, size of the roof, the level of detailing required and the desired service life. Modern waterproofing systems are significantly more reliable and durable than older felt-based products. EPDM, liquid rubber and spray-applied coatings now cover the vast majority of residential and commercial flat roof applications across the UK.
Flat Roof Waterproofing Systems Explained
EPDM Rubber Roofing
EPDM (Ethylene Propylene Diene Monomer) is a synthetic rubber membrane widely regarded as the most durable flat roof waterproofing system available. A single sheet covers the entire roof area with no seams, delivering exceptional weather resistance and a very long service life.
Liquid Rubber HBS200
Liquid rubber waterproofing is applied as a liquid coating that cures to form a seamless, flexible waterproof membrane. It bonds directly to the substrate and is ideal for complex roof shapes, areas with detailing or refurbishment projects where a full membrane isn't practical.
Liquid Rubber SprayGrade
SprayGrade is a spray-applied liquid rubber coating for large commercial and industrial roof areas. It is specified at approximately 600m² per day under suitable conditions; preparation, access, details and weather determine the actual programme. Forti Nova supports system supply and approved-contractor routing.
Prokol Monoseal
Prokol Monoseal is a specialist single-component polyurethane waterproofing coating. Used on flat roofs, balconies, terraces and wet rooms, it delivers a tough, flexible and seamless waterproof finish.
System Comparison at a Glance
| Feature | EPDM | Liquid Rubber | SprayGrade |
|---|---|---|---|
| Application method | Sheet membrane | Brush or roller | Spray applied |
| Best for | Garden rooms, extensions | Complex shapes, repairs | Large commercial roofs |
| Seams | ✅ None (single sheet) | ✅ None (liquid) | ✅ None (liquid) |
| Application speed | Medium | Medium | ✅ Very fast |
| Repairability | ✅ Easy | ✅ Easy | Good |
| Service life | Very long | Long | Long |
| Cold-applied | Yes | ✅ Yes | ✅ Yes |
Which Flat Roof System Is Best for a Garden Room?
For garden rooms, home offices and similar residential structures, EPDM rubber roofing is by far the most widely used system. Its combination of long service life, ease of installation, excellent weather resistance and simple repairability makes it the standard choice across the UK garden room industry.
Liquid rubber systems are the preferred choice for refurbishment work, roofs with complex shapes or areas with significant detailing — where laying a sheet membrane isn't practical.
For larger commercial projects, SprayGrade provides high-output seamless application where the survey and specification support that route. Forti Nova supports system supply, technical scoping, training and approved-contractor routing across the North West.
Working on a commercial roofing project?
SprayGrade spray-applied liquid rubber has a typical output of approximately 600m² per day under suitable conditions. Preparation, access, detailing and weather determine the actual programme. Forti Nova is the UK importer and distributor.
Frequently Asked Questions
What is the best waterproofing system for a flat roof?
Modern flat roofs commonly use EPDM rubber membranes, liquid applied waterproofing systems and spray applied rubber coatings depending on the size and structure of the roof.
How long does EPDM roofing last?
High quality EPDM rubber roofing membranes can last 40–50 years when installed correctly.
What is liquid roofing used for?
Liquid waterproofing systems are commonly used to seal complex roof details, gutters, balconies and concrete structures where seamless waterproofing is required.
Related Systems
Explore the related structural systems, waterproofing technologies and exterior finishes used across modern garden room construction and flat roof waterproofing projects.
Structural Systems
Waterproofing Systems
Exterior Finishes
Technical Resources
Forti Nova supplies EPDM, Liquid Rubber and SprayGrade systems across the North West — serving Blackburn, Preston, Manchester, Bolton, Wigan and Warrington from our Blackburn depot.
Need help choosing the right system?
Call our team or use our guided project enquiry — we'll recommend the right system based on your roof type, size and project requirements.
Regional Coverage
Flat Roof Waterproofing Across the North West
Forti Nova supplies EPDM and liquid rubber waterproofing systems across the North West. Customers searching for EPDM roofing in Lancashire, flat roof systems in Manchester or liquid rubber waterproofing in the North West can call our team for system advice and pricing.
Need Advice on Flat Roof Systems?
Our team can help determine the right waterproofing system for your project — based on roof type, area and application requirements.
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