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What Are Polyurethane Liquid Waterproofing Systems?

What is PU Liquid?

Polyurethane systems and materials are commonly used within the construction industry due to its versatile and robust nature. PU systems are extremely resistant to both extreme temperatures and weather conditions, making it ideal for waterproofing surfaces in all kinds of building projects. Consequently, Polyurethane Liquid systems are becoming increasingly popular within the Roofing Industry as a covering for both Residential and Commercial Flat Roofs. PU Liquids can be cold applied, often with just a roller or a brush, and cure extremely quickly (ranging between 2-24 hours depending on the amount of accelerator used). This saves on both labour and material costs, meaning PU is a great option for your roof covering as opposed to other types of Flat Roof Liquids such as GRP. PU Liquids are extremely tough and can be sufficient on their own once cured, however often a Fiberglass Matting is used in conjunction with the liquid to provide that base layer of protection.

What are The Best PU Liquid Systems?

Due to its growing popularity within the industry, there are now lots of options to consider when deciding on a PU system for your project. This article will briefly run through the best and most popular PU Liquids to use on your roof.

 Desmopol Liquid Polyurethane Waterproofing Membrane:

Desmopol is a high-quality single component PU Liquid that has been used as a waterproofing system for a vast array of projects, including Flat Roofs, Walkways, Balconies, Car Parks and even Swimming Pools. Due to the strength of Desmopol, it can be walked on and is suitable for areas with high amount of foot traffic. These properties give it a large amount of versatility with how and where it can be used, meaning its popularity has surged amongst Contractors and Builders in the past few years. Once cured, Desmopol will form a seamless waterproof membrane without any joints or overlapping needed.

The key advantage to using Desmopol is the array of accessories and products that are available to be used with the main membrane. These products include an accelerator, primer, thickener, topcoat and solvent resistant rollers. This means that its application can be tailored to your individual project, different projects with individual requirements can be supplemented with the use of these accessory products to eliminate error and ultimately save on costs. Desmopol is one of the most versatile Flat Roof Liquids on the market and its proven application as a waterproofing membrane make it a great choice for any project.

Technical Details are as followed:

Life Expectancy: BBA / ETA Certification for life expectancy in excess of 25 years

  • Size: 25kg
  • Colour: RAL 7043 - Grey 
  • Coverage: Approx 15m2 per 25kg tin 
  • Fire Performance: EN 13501, EN 13501 Euroclass E
  • Application: Single Ply Liquid Polyurethane Membrane suitable for application onto Timber, Metal, Plywood, Bitumin & Concrete
  • Life Expectancy: BBA / ETA Certification for life expectancy in excess of 25 years

 Purchase Desmopol here. 


UltraFlex High Performance PU Liquid Waterproofing:

Ultraflex is a high-performance PU liquid that can be used on Flat roofs, Balconies, Terraces, Walkways and Gutters. Coming in a slightly smaller tin of 15kg, Ultraflex is one of the most cost-effective way of waterproofing your surfaces. Ready to use straight out of the tin it has excellent adhesion to different substrates: OSB board, plywood, existing GRP roofs, bitumen membranes, asphalt, metals, brick, concrete, wood etc. Ultraflex can be used without any need for additional catalysers or mixers, however it can be supplied with Thickeners, Accelerators and Topcoats for the projects that will require them.

Technical Details are as followed:

  • Coverage: 15ltr tin coverage = 8 to 10 sqm 
  • Application:  Flat roofs, Balconies, Terraces, Walkways and Gutters.
  • Suitable materials: Excellent adhesion to plywood, OSB board, existing GRP, bitumen membranes, asphalt, metals, brick, concrete, wood etc
  • Guarantee: BBA certified for life in excess of 25 years.

Purchase Ultraflex here .


Icopal Sealoflex Ultima Modified PU Waterproofing System:

The Sealoflex Ultima System is suitable in a variety of applications for both new build and refurbishment projects, either as a complete roof waterproofing solution or as a detailing solution in combination with bitumen and synthetic waterproofing membranes. It can also be used as a waterproofing membrane on balconies and terraces when they are protected e.g., with wooden decking or paving slabs.

It is moisture curing and applied in one operation, making it quick to install and easy to use. Sealoflex Ultima can be applied as a complete roof overlay solution or as a detailing solution in combination with a range of BMI membranes. Manufactured by one of the UK’s leading Roof Material Businesses in BMI, Sealoflex is a high-quality PU application.

Technical Details are as followed:

  • Size: 15Ltr
  • Colour: Grey
  • Coverage: 15L tin = 10m2 coverage
  • Material: Silane Modified Polymer Liquid Applied Waterproofing Membrane
  • Application: Overlay for New Flat Roofs / Concrete / Asphalt / Bitumen / Wood / Metal / PVC / TPO
  • Certification: BBA certificate number 15/522

Purchase Sealoflex here.


ARBOFLEX PU Liquid Waterproofing:

ARBOFLEX® PU is a single component liquid made from pure polyurethane, which once catalyzed forms a seamless elastic membrane, without any joints, overlapping or any integrated mesh needs.

The material properties of ARBOFLEX® PU enable it to be airtight and waterproof on a range of substrates. Thanks to its versatility ARBOFLEX PU adapts to any surface, making it the ideal product for application onto uneven surfaces such as curved or irregular shapes.

Technical Details are as followed:

  • Size: 20kg
  • Colour: Grey
  • Coverage: 1.5 - 1.8 kg per m2 
  • Coverage per tin: 20kg = approx 13m2
  • Application:  Flat roofs, Balconies, Terraces, Walkways and Gutters
  • Suitable materials: Excellent adhesion to cement, concrete, polyurethane foam, butyl, and bituminous sheets, wood, polyurethane plates, metal, etc.
  • Guarantee: BBA certified for life in excess of 25 years

Purchase Arboflex here. 


Polyurethane Liquids are an efficient, flexible and cost effective way to waterproof a variety of Flat Surfaces. Here at Roofing Outlet we stock large amounts of all the systems discussed in this article. 


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