Topseal offer a range of cold liquid applied, high performance, BBA Certified GRP waterproofing systems, which can be used to form a waterproof membrane regardless of the size or complexity of the application. The Topseal systems can be finished in any BS4800 or RAL colour and if required, an anti-slip finish is available for walkway and balcony projects.
A Topseal roof consists of specially formulated Topseal roofing resin and topcoat, cold-applied on site with our heavyweight GRP edge trims to create a bespoke, seamless roof to suit the application. The Topseal systems are installed by our network of trained and approved installers throughout the UK.


Topseal offers a range of advanced GRP waterproofing and roofing systems fitted through a national network of highly trained and approved installers.
Since our system was first installed back in 1992 it has been installed on millions of square metres of roofs all over the UK.
Topseal is the ultimate fibreglass flat roofing system suitable for both domestic and commercial works.
A Topseal roof represents the pinnacle of GRP roofing technology, guaranteed to last a generation, designed to last a life time.
With full BBA certification and up to 40 years materials and workmanship guarantee (with Topseal DoubleTop),Topseal is the ultimate, stylish roofing system. The Topseal roofing systems are installed nationwide and have a proven pedigree as a waterproofing material with an expected lifespan of 100 plus years.


ISO:9001 certified: International quality standard. This international quality standard is independent confirmation that we are focused on delivering customer satisfaction through a reliable and standardised process of operating our business.

ISO:14001 certified: This is the International Standard for Environmental Management. This means we are committed to operating an effective Environmental Management System (EMS) meeting all specified requirements.

BBA Approved. The British Board of Agrément is the UK’s main independent body for verifying a manufacturer’s claims about their product.
These statements are outlined within the Topseal BBA certificate which is available from our website or from www.bbacerts.co.uk (certificate no: 93/2932). This is a guarantee that the stated performance of the product has been independently tested and verified.


The Topseal systems are only fitted by our national network of trained and approved installers.
Any GRP roofing system is only as good as the team that installs it. Every Topseal approved installer has passed the comprehensive Topseal training course, which covers every aspect of installation, product knowledge and customer service. All installers have access to full industry-leading technical support and can install the product to comply with our quality benchmarks.


flat roof repair

1.Vapour check /12mm sub-deck
3.18mm OSB3 T&G deck
5.Topseal A200 edge trim
6.Topseal B260 edge trim
7.Topseal D260 edge trim
8.Topseal C100 edge trim
9.Topseal resin
10.450g/600g m2 reinforcement mat
11. Topseal topcoat


Topseal is the ultimate BBA Certified fibreglass flat roofing system. Topseal GRP (also known as fibreglass) roofing systems are installed exclusively by fully trained and approved installers and supplied with a 20 – 40 year product and workmanship guarantee with the back-up of a full customer service, technical support and quality control team.
Here are just a few of the reasons why Topseal is the ultimate in waterproofing and roofing systems:
• 20-40 year product & workmanship guarantee
• Suitable for domestic, commercial and refurbishment projects
• Versatile and flexible for new build, replacement roofs, listed or iconic buildings
• Only fitted by trained and Topseal approved installation teams UK wide
• Environmentally sustainable by design and safe to install. No heat required
• Rated A/A+ in the generic BRE Green Guide
• Fire Retardant and completely UV resistant
• Over 1,000 different combinations of colours, and specialist finishes available
• Specification and technical support available
• NBS specification available
• Installer and specifier login areas available
• BBA certified system
• Simulated lead design available
• RIBA approved CPD


25 & 30 Year Guarantees

We are so confident with the quality of our GRP roofing systems that we offer 25 and 30 year guarantees, to give you peace of mind that our product is designed to last. The 25 year guarantee comes with each of our standard installations. The 30 year guarantee is available with our HD roofing systems but this does not include walkways, terraces, balconies or areas subject to heavy foot traffic (a 25 year guarantee will be issued for these).

40 Year Guarantee

Our Topseal DoubleTop system is designed to be an extremely durable flat roofing system and we’re so confident with it that we’re offering a 40 year guarantee on each installation. Once installed, you won’t have to worry about your roof leaking, as it’s completely watertight and designed to last.


The Topseal system can be used on practically any type of roof including small domestic extensions, garages, dormer roofs, parapet walls, gullies, gutters, conservatories or orangeries right through to large commercial projects. It will fit in with a building of any age, from listed to ultra-modern. For more demanding applications, Topseal HD, DoubleTop and Green Top are designed to deliver the same high performance, under extreme conditions.

The Topseal high-performance roofing system is suitable for nearly all roofing applications and can be specified to the latest Part ‘L’ regulations. The Topseal system uses a 450g/m2 roofing-grade reinforcement mat along with our roofing resins and topcoats for the finest roofing system that money can buy.

The Topseal Heavy Duty system is suitable for heavy, frequent foot traffic such as walkways, balconies and stairs or for any flat roof where a heavy-duty specification is required. The Topseal HD system uses a 600g/m2 roofing-grade reinforcement mat along with our roofing resins and topcoats and our non-slip coating for the perfect finish.

The Topseal double-top system is designed for projects that require extreme durability. The system can be used for almost any roofing application with our 2 x 450g/m2 laminate formed with our specially formulated roofing resin and topcoats. Topseal double-top can also be used for water-containment specifications.

Topseal Green Top is the complete green roofing system with an optional sedum or wildflower livingroof finish. The system includes our Double Top system of 2 x 450g/m2 laminates along with our specially formulated resins and topcoats to finish the perimeter edges in your choice of colour.

(1) Vapour check /12mm ext. ply sub-deck
(2) Insulation
(3) 18mm OSB3 deck
(4) 450g/m2 reinforcement
(5) Topseal roofing resin
(6) Topseal Topcoat layer
(7) Topseal GRP edge trim
(8) 600g/m2 reinforcement
(9) Drainage/moisture retention layer
(10)GreenTop substrate
(11) GreenTop sedum
(12) Caledonian pebble border
(13) Retention strip
(14) Drainage retention strip
(15) Pre-existing Substrate
(16) Primer

*The guarantee for each system maybe subject to change, please check with the Topseal office for the guarantee period on your chosen system


Topseal offers a range of roofing solutions for common domestic applications such as extensions, garages, dormer roofs, parapet walls, gullies, gutters, conservatories, orangeries and many more using the Topseal fibreglass (also known as GRP) roofing systems.

The Topseal roofing system can be used on a variety of domestic roofing projects including new builds and refurbishment projects, it is also suitable to be used for cold and warm roofs depending on your requirements. The versatility of Topseal will ensure that it will fit in with almost any style from ultra-modern to traditional listed buildings,
providing long-lasting performance and style through the most extreme weather conditions.

Topseal is also accepted by the NHBC when installed and used in accordance with our BBA Certification.
Select Topseal HD for an extra durable system with a 30 year guarantee or Topseal DoubleTop for a flat roofing system with extreme durability and a 40 year guarantee.

fibreglass roofing


Topseal is widely used for a variety of commercial and industrial applications. Our system is cold applied without the need for heat or flames and cures within an hour of installation making it much quicker than many other liquid applied systems and coatings. For technically challenging projects, Topseal is one of the most versatile roofing systems available. The ease of use to encapsulate or incorporate almost any detail has led to it being frequently specified for waterproofing difficult gutters or areas with a high level of complexity including, tanking, lining and gullies in any pitch to vertical. Topseal is BBA approved, has fire retardant properties to BS476 part 3 EXT.F.AA, is available in a range of colour and finish options and is only fitted by our trained and approved installers.

Select standard Topseal system for a 25 year guarantee, Topseal HD for an extra durable system with a 30 year guarantee or Topseal DoubleTop for a flat roofing system with extreme durability and a 40 year guarantee.

grp flat roofing


Topseal fibreglass roofing system is used extensively as a lead/copper replacement or alternative for roofs, gutter linings and complex architectural detail work.

For listed buildings Topseal can also be used to simulate rolled joints without seams. Colour matching can be achieved by using a topcoat with a lead grey or copper green finish providing like-for-like appearance and long-lasting performance with a guarantee of up to 40 years.

Topseal is also free from toxic water run-off associated with lead and copper and deters criminal damage due to its high durability and low effective scrap value.

Select the standard Topseal system for a 25 year guarantee, Topseal HD for an extra durable system with a 30 year guarantee or Topseal DoubleTop for a flat roofing system with extreme durability and a 40 year guarantee.


Topseal GreenTop can be used to create a totally bespoke green roof with a low maintenance sedum green roof, sedum tile system or prepared to suit third party supply of the green roof.

As well as creating a naturally beautiful area Topseal GreenTop adds sound insulation to your property and delivers energy savings as it protects your property from internal temperature fluctuations in the summer and winter months. The system is provided with Topseal’s class-leading 25 year watertight guarantee for peace of mind.


For heavy-duty applications such as balconies, walkways, terraces, roof gardens and steps, Topseal HD provides an extra level of performance and waterproof protection with a 25 year guarantee on areas subject to frequent foot traffic. The system is fitted with a choice of our coated aggregate finish which is available in any of our standard colour options or matched to most RAL or BS4800 colours or our anti-slip finish for extra grip in wet conditions. Balustrade supports, tiles or decking can be easily incorporated into the system providing limitless possibilities for your next project.


Topseal GRP Roofing
Topseal’s single-ply GRP laminate can be installed to any size, in any BS4800 or RAL colour and to any degree of complexity, without any seams, welds or joints and it comes with a minimum 20-40 year guarantee.

Standards Compliance
– BBA (British Board of Agrément) Certificate Number:
93/2932 (see opposite page.)
– Fire retardant to class 1 if required
– Part L Building Regulations Compliance (as of April 2006):
To comply with the Part L Regulations of April 2006 the following specification would be required to obtain a ‘U’ value of 0.25 installed as shown below:
12mm Ply sub deck
100mm of Kingspan TR26 or equivalent
18mm T&G OSB3 board
Topseal laminate
-Part L Buildings Regulations Compliance, for up to date regulations please refer to http://www.planningportal. gov.uk/buildingregulations/approveddocuments/partl

Finish Options
– Colour range: Topseal is available in 3 shades of grey as standard: Cool Grey, Dark Admiralty and Anthracite.
– Topseal holds a stock of its most popular BS4800 colours
(colour chart available on request.) A Topseal roof can be
specified in any BS4800 or RAL colour.
– A Topseal roof can be specified with a non-slip
aggregate finish.
– Available in 450g/m2 and 600g/m2. Please refer to the
front of the manual to choose the correct system for
your application.

Properties and Performance
Weight – A 450g/m standard Topseal laminate installed onto OSB3 18mm T&G boards is rated at (approx) 13.3kg/m2 (OSB3 18mm T&G= 11kg/m2, Roofing resin= 1.35kg/m2, CSM= 450g/m2, topcoat = 0.5kg/m2) Weather tightness (Excerpts from BBA certificate.) The system is impervious to water and, when used in the systems described, will give a weather tight roofing capable of accepting minor structural movements without damage.

Resistance to wind uplift
The system has adequate resistance to the effects of wind suction likely to occur within practice.

Properties in relation to fire
A system comprising Topseal applied to an 18mm thick Sterling Board substrate, when tested to BS476: Part 3: 1958, was designated EXT.F.AA.A system comprising Topseal laminate applied to 15mm OSB3 board when tested to prEN 1187; tests 1, 2 and 3, achieved Classification Broof (t1) Broof (t2) and Broof (t3) respectively.

A Topseal GRP laminate constructed in accordance with the installation section and formed in satisfactory weather conditions can be expected to maintain its integrity and show no measurable loss of physical properties for a period of 30 years or more.

Test (Units)MethodMean Result
Thickness (mm)Dial Gauge1.75
Apparent density (kgm-3)ISO 11831360
Glass/Resin RatioBS.27823.5:1
Barcol HardnessBS.278235
  1. B260 edge trim
  2. D260 edge trim
  3. C100 edge trim
  4. A200 edge trim
  5. C1 universal external corner
  6. 6 8’ x 2’ 18mm OSB3 T&G decking
  7. 450g/m2 Chopped Strand Mat
  8. Topseal laminate
  9. Topseal topcoat layer



Part L Reg’s Application
A Topseal roof can be easily configured in either a warm or cold roof specification. For a warm roof, a sub-deck is first fixed to the joists at 300mm centres. A vapour check and insulation sheet is then laid over the top. Insulation sheets can also be purchased with a vapour check adhered to one side. The decking should then be fixed on top
as it normally would be, screws should be used to fix the boards to the joists and these should penetrate through the insulation and into the joists to the same depth as standard fixings. It is imperative that all layers of the roof are pressed firmly together and that there are no gaps between any of the layers.

The GRP should then be laminated over the top of the roof as normal. These roofs will usually require larger edge trim sizes such as A250 and B300. To comply with the Part L Regulations of April  2006 the following specification would be required to obtain a ‘U’ value of 0.25 installed as shown below:

12mm Ply sub deck
100mm of Kingspan TR26 or equivalent
18mm T&G OSB3 board
Topseal laminate
-Part L Buildings Regulations Compliance, for up to date regulations please refer to http://www.planningportal.gov.uk/


A170: This is designed for applications where it is not possible to use the larger A200 trim.
A200: This is the standard size drip trim.
A250: This drip trim is designed and ideally suited for use on warm roofs.
The A type trim is a drip trim, fitted to the lowest edge of the roof  usually where the rainwater flows into the gutter.
Two support battens should be fixed to the perimeter of the roof to provide space for the gutter to fit behind the trim, with the outer batten attached 10mm lower than the inner batten to allow the trim to sit flush with the roof.


B230: This is the smallest size of raised edge trim fitted to the edges of the roof to contain and direct the flow of water.
B260: This is the standard size raised edge trim.
B300: This larger raised edge trim is designed for use on warm roofs.

B trim is a raised edge trim, a single batten is fixed level with the top edge of the deck. If a ladder is likely to be leant against a B trim for regular access to the roof, the trim will need to be reinforced to avoid deformation. The trim can either be doubled up by slotting a section of extra trim within the section where the ladder will be used or it can be reinforced with an extra layer of Topseal GRP laminate and the tissue to maintain a smooth finish.


C100: The standard simulated lead flashing with 100mm vertical face and 35mm wall penetration.
C100MT: As C100 description with self-securing moisture trap.
C100L: (Long leg) As C100 description with 50mm wall penetration.
C100LMT: (Long leg with moisture trap) As C100 description with 50mm wall penetration and self-securing moisture trap.
C150: Simulated lead flashing with 150mm vertical face and 35mm wall penetration.
C150MT: As C150 description with integral, self-securing moisture trap.
C150L: (Long leg) As C150 description with 50mm wall penetration.

The C trim is a simulated lead flashing, generally fitted in conjunction with the D trim.

C7INT + C7EXT: To be installed on internal and external corners prior to fitting flashings.


D260: Angle fillet trim with 135mm and 70mm flanges.
D300: Angle fillet trim with 175mm and 70mm flanges.

The D trim is a fillet trim for use against abutting walls. It will also provide expansion and perimeter ventilation and is compatible with the C2 and C3 universal corners.


F300: Flat sheeting supplied in 300mm width in 5m, 10m and 20m  rolls.
F600: Flat sheeting supplied in 600mm width in 5m, 10m and 20m rolls.
F900: Flat sheeting supplied in 900mm width in 20m rolls.

The F trim is a flat flashing, mainly used at the intersection of a pitched roof and flat roof often found on dormers.The F trim should not be laminated over completely as it will crack. There are many other applications for the F trim including vertical details where laminating would be time consuming, under the feet of air  conditioning units to enable re-roofing without disconnecting and use on some parapet wall details etc. The trim should be nailed to the deck around its edges and bandaged over any joins and nail penetrations. Any unlaminated trim can be top coated with the rest of the roof.



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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