Topseal PU (Polyurethane) is a high-performance flat roofing system with guarantees of 20 & 25 years which comprise of: Topseal PU Primer (if required), Topseal PU Basecoat and Topseal PU Topcoat, fully reinforced with 225gm chopped strand reinforcing mat.

These systems are moisture triggered polyurethane membranes that cure together to form a seamless, durable waterproof coating for all flat roof types.

The 25-year system carries EXT AA fire rating to BS 476 Part 3: 2004 and B Roof (t4) to BS ENV 1187: 2002.


Features & Benefits

  • Long term peace of mind – 20 or 25-year lifespan
  • BBA Certified
  • Independently tested fire resistance ratings to comply with legislation
  • Totally seamless – No weak spots
  • UV resistant – Will not crack through embrittlement from sunlight
  • Can be used over existing substrates as well as new ones.
  • No limitations in roof size
  • Liquid formula allows complex detailing to be simplified.
  • Will not chalk – Remains aesthetically pleasing and less prone to early failure
  • Single pack formulations – Less material waste and packaging
  • Fully bonded to deck system – resistant to wind uplift
  • Solvent free – low odour
  • Cold applied so safe to use

What is Topseal PU / Polyurethane?
Topseal PU is a high performance, moisture cured, single component, glass fibre reinforced aliphatic polyurethane, for use on new and existing flat and pitched roofs.

Is Topseal PU a certified system?
Yes, Topseal PU has achieved BBA Certification. It is also manufactured and registered as meeting ISO9001:2015 standards.

Does Topseal PU have fire certification?
Yes, the 25-year system carries an EXT AA fire rating to BS Part 3:2004 which is the highest fire rating available for flat roofing systems. Along with this, we have also achieved B Roof (t4) to BS ENV 1187:2002 standards.

How long is Topseal PU guaranteed for?
There are various options available in regard to the guarantee. The length of guarantees available are 20 and 25 years dependent on the requirements of the project and budget. In addition to the materials guarantee, a Topseal PU roof is backed by a workmanship guarantee which runs concurrently with the materials guarantee. Further optional insolvency guarantee and a 10-year Insurance Backed Guarantees are also available.

Who can install a Topseal PU roof?
Topseal PU is only available to Topseal Approved Contractors and not available off the shelf. This gives the customer peace of mind that the contractor carrying out the work has been fully trained in using our systems.

Is it a safe system to install?
Yes, very. Topseal PU is a cold applied system which requires no hot works, making it very safe to use. Along with this, our system is solvent free making it low odour.

Where can Topseal PU be installed?
Their limits are endless with Topseal PU and where it can be used. Topseal PU can be used on both domestic and commercial new build and refurbishment projects. From something as small as a porch, through to apartment blocks, leisure centres, hospitals, box gutters, timber framed buildings and right up to factory roofs which can be 1000’s of sq. metres without the need of expansion details. Due to the properties of Topseal PU, it can also be used on vertical faces and upside-down without any slumping occurring.

Onto what substrates can Topseal PU be installed?
Topseal Polyurethane can be installed onto various substrates including: – bituminous roofing membranes, mastic asphalt, concrete, steel, asbestos, GRP, lead, OSB3, single-ply, aluminium, paint, plywood, polyurethane foam, liquid-applied roof waterproofing and foil backed insulation.

Why use Topseal PU as opposed to GRP?
Topseal PU is the system of choice for use on larger projects as there are no size restrictions, requirements of expansion joints or trims at junction details. This saves both time and money on labour and materials.

Can you walk on a Topseal PU roof without it getting damaged?
Yes, a Topseal PU roof will withstand foot traffic. You can also add slate granules to the finish to give it a non-slip finish and more hard wearing.

What other application can you use Topseal PU the system for?
Topseal PU can also be used for irrigated green roofs or roof gardens, inverted warm roofs and zero fall roofs applications. Paving slabs and decking can also be installed onto a fully cured Topseal PU roof. The versatility of Topseal PU is so good that it can even be used on existing pitched tile roofs.

Is it only available in dark grey?
Dark grey is our standard off the shelf colour, but there are 5 others colours available:- mid grey, light grey, terracotta, copper green and white.

Can a Topseal PU roof be repaired, should it become damaged?
Yes, in the unlikely event of damaging the roof membrane, the repair of minor damage to the system can be achieved effectively by cleaning back to the unweathered material and recoating the damaged area with the Topseal PU system.

What are the other benefits of a Topseal PU roof?
Firstly, it is totally seamless, there are no joints, seems or welds meaning there are no weak spots on the roof with the potential to fail. It is UV resistant, so it won’t be broken down over time due to exposure to the sun along with this, it doesn’t become brittle with age unlike other systems. It is resistant to temperatures of over 60°C for long periods. Topseal PU is also a fully bonded system, which means it is resistant to wind uplift.

How can I get more information about technical details and specifications?
Here at Topseal we pride ourselves on the technical support that we offer to our contractors, architects, specifiers, surveyors, other construction professionals including their clients. If you require any technical assistance you can contact us on 01423 886495 or by email

How can I get a Topseal PU roof installed?
A Topseal PU roof can only be installed by a Topseal Approved Installer and we have a network of contractors which covers the whole of the UK. Contact us on 01423 886495 or by email and we can provide you with contractors details who cover your area.



Every Topseal installer is allocated a unique verification number to prevent 3rd party misrepresentation. You should always ask any Topseal installer for their verification number.

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