Decothane Ultra
Supply and installation of Decothane Ultra — a premium cold-applied, liquid polyurethane waterproofing membrane providing seamless, durable protection for flat roofs, balconies, and complex roof details.
As approved contractors, Guaranteed Roofing Solutions Ltd supply and install Decothane Ultra systems to the full manufacturer specification, backed by long-term guarantees across Cambridge, Essex, Hertfordshire, Bedfordshire and East Anglia.
What is Decothane Ultra?
Decothane Ultra is a single-component, moisture-curing aliphatic polyurethane liquid waterproofing membrane manufactured by Sika Ltd. It is designed for use on flat roofs, balconies, and other exposed surfaces where a seamless, fully-bonded waterproof solution is required.
Unlike traditional sheet membranes, Decothane Ultra is applied as a liquid, flowing into every contour and detail of the roof surface. Once cured, it forms a tough, flexible, monolithic membrane that cannot delaminate at seams — because there are none.
The system is cold-applied, meaning no naked flame or hot works are required. This makes it ideal for occupied buildings, sensitive structures, and roofs with complex detailing where traditional torch-on systems would be impractical or high-risk.
System at a Glance
- ManufacturerSika Ltd
- TypeSingle-component aliphatic polyurethane
- Application MethodCold applied — roller, brush or squeegee
- Elongation800%+
- Tensile Strength≥ 10 N/mm²
- UV ResistanceExcellent — aliphatic formulation
- GuaranteeUp to 25 years (contractor applied)
- BBA CertifiedYes
- Suitable SubstratesConcrete, plywood, metal, felt, GRP
Key Benefits
A high-performance system trusted by contractors and specifiers across the UK
Seamless Waterproofing
Fully bonded, seamless liquid membrane eliminates joints and seams — the most common points of failure in traditional systems.
Highly Flexible
Elongation of over 800%, accommodating structural movement and thermal expansion without cracking or delaminating.
UV Stable
Aliphatic topcoat provides exceptional UV resistance and colour stability, maintaining performance in all weather conditions.
Fast Cure
Walk-on time in as little as 1–2 hours and fully cured within 24 hours, minimising disruption to your building or business.
25-Year Guarantee
Manufacturer-backed guarantees of up to 25 years when installed by approved contractors like Guaranteed Roofing Solutions.
Cold Applied
No open flame required during installation — safer for occupants, contents, and structures, including sensitive buildings.
How We Install Decothane Ultra
Every installation follows the manufacturer's full system specification for guaranteed performance
Substrate Preparation
The existing roof surface is thoroughly cleaned, primed and any deteriorated areas are repaired to create a sound base for the system.
Primer Application
A specialist primer is applied to promote adhesion of the Decothane membrane to the substrate, ensuring a fully bonded finish.
Base Coat
The first coat of Decothane Ultra liquid membrane is applied at the specified thickness, embedding reinforcement fleece at critical junctions.
Reinforcement Layer
Polyester reinforcement fleece is fully embedded into the base coat at all upstands, drains, details and high-stress areas.
Top Coat
A second coat of Decothane Ultra is applied to achieve the full system thickness and provide the UV-stable, weatherproof finish.
Inspection & Sign-off
A full inspection ensures the system meets specification, with guarantee documentation issued upon successful completion.
Ideal Applications
Decothane Ultra is suitable for virtually any flat or low-pitched roof application, and is especially effective where complex detailing, multiple penetrations, or refurbishment over an existing system is required.
- Flat roofs & low-pitched roofs
- Balconies & terraces
- Podium decks
- Walkways & car park decks
- Gutters & valleys
- Roof details & upstands
- Skylights & rooflights
- Refurbishment over existing systems
Suitable Substrates
Decothane Ultra can be applied directly over most existing roof substrates, making it ideal for refurbishment without costly tear-off:
- Concrete & screed
- Plywood & OSB decking
- Metal profiled sheets
- Existing felt or bitumen
- GRP (fibreglass)
- EPDM & TPO membranes (primed)
- Asphalt
Why Choose Guaranteed Roofing Solutions?
Approved Installer
Fully approved by the manufacturer to install Decothane Ultra to guarantee specification.
20+ Years Experience
Extensive experience in liquid applied and single ply roofing systems across commercial and domestic sectors.
Full System Supply
We supply and install the complete system — one point of contact and accountability for the whole project.
Manufacturer Guarantee
Long-term guarantees backed directly by the manufacturer, providing full peace of mind.