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Splayed Bay Window Roof

Flat roof - lead effect GRP

Stormking Plastics Ltd Variant:
Third party certifications:
  • BBA Agrément Certificate

    BBA Agrément Certificate

    Certificate type

Prefabricated GRP bay window roofs.

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For as use as complete roof elements to bay windows forming part of the external wall of domestic buildings.


The Stormking prefabricated GRP bay window roof consist of a preformed structural timber-frames, with internal timber supports, fully bonded to GRP ceilings, fascias and soffits and incorporate either 110 mm PUR spray foam or 200 mm mineral wool quilt thermal insulation, laid over a vapour control layer (VCL).

Pitched roofs incorporate an outer moulded fire-retardant GRP shell, or are unfinished, for conventional roof tiling over battens carried out on site. Flat roofs incorporate an outer moulded GRP shell manufactured using fire retardant resins.

Features and benefits:

  • Available in three styles: flat roof lead-effect GRP, incorporating a slight fall towards the outer edge to allow rainwater run-off, pitched roof lead-effect or tile-effect GRP available with falls between 30°–70°) and pitched roof with timber-frame only (available with falls between 30°–70°).
  • The units are built around timber framework and, where specified, a preformed GRP outer moulded shell is added and trimmed prior to finishing.
  • BBA certified and independently assessed to UKAS standards.
  • Modern GRP technology for perfect recreation of natural materials.
  • Tight tolerances to your design specification.
  • Greater design flexibility that is repeatable in volume.
  • Hand-checked quality control by full-time quality managers.
  • Dry fit, requiring no specialist trades for installation.
  • Ideal for high strength to weight requirements.

General information



A range of colours are available upon order, consult manufacturer for details.


Choose from various styles and finishes: Curved Lead Flat Lead Lean to Lead Lean to Tiled Lean to Trussed Pitched Lead Pitched Tiled Pitched Trussed Please contact manufacturer with specific design related questions/enquiries.




Timber framework.

Glass Reinforced Plastic (GRP)

Preformed GRP outer moulded shell is added and trimmed prior to finishing.


Two year

From delivery.


Pr_35_90_28_33 Glass fibre-reinforced plastics (GRP) roof componentsPrimary


H40/130 Proprietary GRC components

H41/140 GRP proprietary features

Specification data - Glass fibre-reinforced plastics (GRP) roof components

Component type

Flat roof - lead effect GRP.


All three styles are manufacturer in a wide range of sizes to suit a range of bay window roof shapes and styles.

Consult manufacturer for details and/or specific design related questions/enquiries and insert requirements.

Fire performance


External face

To BS EN 476-3, EXT.S.AC.

Finish as delivered

Lead effect GRP.


Any colour (colour matching), consult manufacturer.

Insulation material

Not required.

PUR spray foam.

110 mm.

Thermal transmittance: To BS EN ISO 6946: 2007 0.026 W.m -1.K -1.

Mineral wool.

200 mm thick.

Thermal transmittance: To BS EN ISO 6946: 2007 0.044 W.m -1.K -1.

Roof pitch

Not applicable.

Environmental information

Country of product manufacture

United Kingdom

BIM objects

Platform Compatible Version



Stormking Bayroofs Product Brochure

Stormking Bayroofs Product Brochure

Stormking Installation Guide - Flat Bay Window Roof

Stormking Installation Guide - Flat Bay Window Roof

Third party certifications

BBA Agrément Certificate

BBA Agrément Certificate

Stormking GRP Prefabricated Roofs, Stormking Prebricated GRP Bay Window Roofs - British Board of Agrément Certificate

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