7.2 Pitched roofs

Also see:

Part 8.0

7.2.26 Solar roof panels

Solar roof panels should be securely fixed and not adversely affect the weather resistance of the building. Where the solar roof panels form the roof covering, they should be of suitable quality and durability to protect the building from weather. Issues to be taken into account include:

  1. weather tightness
  2. fixing
  3. ventilation and vapour control
  4. durability.

Weathertightness#

Integrated solar roof panels should meet the weathertightness criteria in Part 8.0 ‘Internal services and low or zero carbon technologies’.

The installer should consult the tile or slate manufacturer prior to installing solar roof panels, to ensure compatibility with the tile or slate and weathertightness.

Connections may need to penetrate though the outer weatherproofing layer, which may potentially affect the roof covering, underlay and insulation of a roof. All penetrations should be carefully detailed, and appropriate flashings, etc used in accordance with the manufacturers recommendations, to ensure the weathertightness of the penetration.

Mounting brackets which pass through the tiling or slating should not affect:

  • the weathertightness of the tiles or slates
  • the stability of the tiles or slates.

Proprietary flashing kits should be used around integrated solar roof panels. Flashing kits should ensure the weathertightness of the array and be installed to avoid excess gapping, sagging or kicking of the tiles or slates and be fixed in accordance with manufacturer recommendations.

Fixing#

Where solar roof panels are installed to the roof, these maybe either:

  • the ‘on-roof’ type and sit above the roof covering or
  • integrated into the tile or slate array, to also form the roof covering.

Solar roof panels maybe secured:

  • to the roof framing or
  • to roofing battens or
  • to both the roof framing and roofing battens.

Solar roof panels should be secured in accordance with manufacturers requirements and be capable of resisting wind uplift and snow loads for the building and its specific location, see also Part 8 ‘Services’.

Roofing battens, should be adequately fixed where used to secure solar roof panels. Batten fixings should be capable of resisting wind forces in accordance with BS 5534 (Annex H.7 ‘Batten fixing penetration’), see also Clause 7.2.17.

Ventilation and vapour control#

Where arrays of integrated solar roof panels are installed, forming the roof covering, then the roof covering should be treated as air impermeable and the whole roof ventilated accordingly, unless the panel manufacturer is able to demonstrate their system is air permeable, guidance on roof ventilation strategies can be found in Clause 7.2.15 of this chapter.

Solar roof panel manufacturers may also require a ventilated air space beneath the panel, to increase ventilation and cooling of the panel.

Durability#

Solar roof panels and associated brackets, fixings, flashings and trims should be adequately durable and suitable for their location.

Appropriate materials should be selected for flashings, guidance can be found in Clause 7.2.20 of this Chapter.

In aggressive environments such as coastal locations, grade 316 stainless steel fixings and brackets are recommended.

Last updated: 2nd January 2024

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