Widopan Products

Widopan FD Roof Waterproofing System

Manufacturer: Widopan Products 

Materials: Flexible Polyesters 

The Widopan FD Roof Waterproofing System is a three-part, unsaturated polyester resin, reinforced with polyester fleece.

Widopan FD resin has the nominal characteristics of:
Specific gravity (g·cm–3) 1.013
Curing with activator (minutes)
time to rain resistant 20
time to foot-traffic accessibility 30
Flashpoint (°C) 34
Colour anthracite and light grey

BBA logo

Number: 07/4488 PS1
Issue date: 15/12/2020

ETA logo

Number: 05/0210
Issue date: 26/10/2017

Approved for use on

Balconies, Terraces & Walkways Blue Roofs Brown Roofs Flat Roofs Green Roofs Inverted Roofs Pitched Roofs Podium Decks Roof Gardens 

for use as a waterproofing layer in:

• warm or cold exposed roofs on flat, zero-pitch roofs and pitched roofs with limited access
• inverted roof specifications using aggregate ballast on flat roofs, including zero-pitch roofs with limited access
• protected inverted roof specifications using pavers or other suitable protection on flat roofs, including zero-pitch roofs with limited or pedestrian access
• green roof (extensive) specifications on flat roofs, including zero-pitch roofs with limited or pedestrian access, or pitched roofs with limited access
• roof garden (intensive) specifications on flat roofs, including zero-pitch roofs with limited or pedestrian access
• brown roof specifications
• blue roof specifications
• podium decks
• balconies with pedestrian access
• walkways


Concrete Insulation Boards Metal Mineral Wool Insulation Plastic PUR or PIR Insulation Reinforced Bituminous Membranes Timber 

The system is suitable for use on the following substrates:

• concrete
• plastic
• wood
• metal
• reinforced bitumen membranes (including mineral-surfaced)
• PUR or PIR insulation boards
• mineral wool insulation batts


35 Years 

Accelerated weathering test data confirm that a satisfactory retention of properties is achieved. All available evidence indicates that the system should achieve an initial life expectancy of at least 35 years. When fully protected and subject to normal service conditions in an inverted roof specification with an open covering (eg aggregate pavers), the system can provide an effective barrier to the transmission of liquid water and water vapour for the design life of the roof in which it is incorporated.

However, in situations where maintenance or repair of any of the components in the roof structure are necessary (eg protection layer, insulation), the durability of the membrane may be reduced. In these circumstances the Certificate holder should be consulted.

An estimation cannot be given for the life of green roof and roof garden specifications owing to the nature of use; however, under normal circumstances, it should be significantly greater than for open coverings.

Installation Requirements

The system should only be installed by contractors who have been trained and approved by the Certificate holder.

Puncture Resistance

P1 - non accessible

Least compressible (eg concrete)

P4 - roof gardens, inverted roofs and green roofs)

Most Compressible Substrate (eg insulation)

Fire Safety

When tested to DD CEN/TS 1187 : 2012, Test 4, a system comprising an 18 mm plywood primed with Widopan Primer, and with the Widopan FD resin applied in two coats, reinforced with a non-woven polyester, achieved Class BROOF(t4)(1).
(1) Exova Warringtonfire, Test report No 338068. Report available from the Certificate holder.

In the opinion of the BBA, a roof incorporating the system will be unrestricted in terms of proximity to a boundary under the national Building Regulations in the following circumstances:
• Protected or inverted roof specifications, including an inorganic covering listed in the Annex of Commission Decision 2000/553/EC,
• a roof garden covered with a drainage layer of gravel 100 mm thick and a soil layer 300 mm thick,
• irrigated roof gardens, green roofs and brown roofs.

The designation of other specifications should be confirmed by reference to the requirements of the documents supporting the national Building Regulations.

The system, when used in pitches of greater that 70°, excluding upstands, should not be used on buildings in England and Wales that have a storey at least 18 m above ground level and contain: one or more dwellings, an institution, a room for residential purposes (excluding any room in a hostel, hotel or boarding house), student accommodation, care homes, sheltered housing, hospitals or dormitories in boarding schools.

If allowed to dry, plants used in a roof garden may allow flame spread across the roof. This must be taken into consideration when selecting suitable plants for the roof. Appropriate planting irrigation and/or protection should be applied to ensure the overall fire-rating of the roof is not compromised.

Certified Products

The following products are also covered by the same certification:

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Widopan Products

Systems House
Horndon Industrial Park
West Horndon

T : 0845 265 8008

E : info@widopan.co.uk

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