Preparing Industrial Roofs For Commercial Solar Panels
Commercial solar panels are a long-term investment.
The industrial roof beneath them should be assessed, repaired and, where necessary, refurbished before the solar array is installed.
The Roof Comes Before the Solar Array
Commercial solar installations are commonly intended to remain in place for 20 to 30 years. Installing them over an ageing or deteriorating industrial roof can create a significant future liability if the roof requires repair or replacement before the solar system reaches the end of its intended service life.
Once panels, mounting rails, cabling and associated equipment have been installed, access to the roof covering becomes more difficult. Repairs may require part of the solar array to be disconnected, removed and subsequently reinstated.
Assessing the roof before installation allows existing defects to be identified and an appropriate programme of repair or refurbishment to be completed while the roof remains fully accessible.
Aligning the Roof with the Solar Investment
A solar installation does not prevent an existing roof defect from progressing.
Corrosion, failing roof-sheet coatings, deteriorated fixings, brittle rooflights and defective gutters can continue to deteriorate beneath or around the completed array. Problems that might once have been straightforward to address can become considerably more disruptive after the solar installation is operational.
The objective should be to establish whether the roof covering has a realistic remaining service life compatible with the proposed solar installation.
Where it does not, the roof should be repaired, refurbished, overclad or replaced before the panels are installed.
Pre-Installation Roof Condition Assessment
The condition of the roof covering should be considered separately from the structural assessment required for the solar installation.
A roof condition assessment may include consideration of:
Existing roof-sheet condition
The age and condition of the roof sheets, including deterioration of the original factory-applied coating, corrosion and previous repairs.
Cut edges and sheet laps
Corrosion affecting cut edges, end laps and other vulnerable areas should be identified and treated before access becomes restricted.
Roof fixings
Corroded, loose, over-tightened or unsuitable fixings may require treatment or replacement as part of the refurbishment work.
Rooflights
Older rooflights can become brittle, discoloured and difficult to maintain. Replacement should normally be considered before installing a long-term solar array around them.
Gutters and drainage
Internal gutters, outlets and drainage routes should be inspected and repaired where necessary. The solar layout should not obstruct drainage or make essential maintenance impractical.
Previous coatings and repairs
Existing coatings, mastics and patch repairs should be assessed for adhesion, compatibility and remaining serviceability.
Structural Suitability Remains Essential
Roof coating and repair work cannot determine whether the building is structurally capable of supporting a solar installation.
The solar designer and appointed structural engineer must consider the supporting structure, wind loading, imposed loads, roof-sheet thickness, roof-sheet fixings and the proposed mounting system.
Current MCS requirements state that the installation must maintain the building’s structural safety, fire safety and weather-tightness. For brackets fixed directly to metal roof cladding, the roof-sheet thickness and the attachment of the cladding to the main structure must also be checked.
Liquasil’s involvement is limited to the condition and suitability of the roof covering and the specification of appropriate repair or protective coating work.
Metal Roofs Before Solar Installation
Older profiled metal roofs can often be refurbished without removing the existing sheets, provided that the roof remains structurally suitable and the extent of corrosion is manageable.
Preparation may include:
- Treatment of cut-edge corrosion
- Repair or replacement of defective fixings
- Removal of loose or delaminating factory-applied finishes
- Replacement of unsuitable rooflights
- Localised repairs and sealing
- Refurbishment of gutters
- Application of a protective roof coating system
Where a specification-grade system is required, Metalseal provides a BBA Approved metal roof coating system with a 25-year product warranty.
The completed coating protects the accessible external surface of the roof sheets. It does not provide structural strengthening or resolve corrosion originating from inaccessible sheet undersides.
Asbestos Cement Roofs and Solar Panels
Asbestos cement roofing has not been permitted in UK construction since 1999. Even the newest remaining roofs are therefore more than 25 years old, while many have been in service for considerably longer.
Older asbestos cement roofs require particularly careful assessment before a commercial solar installation proceeds.
Their age, condition, fragility and supporting structure may mean that overcladding or replacement provides a more appropriate long-term solution than retaining and coating the existing sheets.
A protective coating does not strengthen asbestos cement, remove its inherent fragility or make an unsuitable roof appropriate for solar equipment.
The roof and supporting structure should therefore be independently assessed before the solar mounting system is designed.
In many cases, completing an overcladding or replacement programme before installing the solar array will provide the more practical long-term solution.
Why Complete the Roofing Work First?
Addressing the roof before the solar installation can provide several practical advantages.
Unrestricted access
Repairs and coating work can be completed without working around mounting rails, panels and electrical equipment.
Reduced future disruption
The likelihood of requiring premature panel removal to reach an underlying roof defect is reduced.
Clearer responsibility
The condition of the existing roof can be documented before the solar installer begins work.
Better project coordination
Roofing and solar programmes can be planned in the correct sequence rather than treating roof defects as an unexpected variation.
Long-term asset planning
The building owner can make an informed decision about whether refurbishment, overcladding or replacement is the most appropriate investment.
Support for Commercial Solar Contractors
Liquasil works with commercial solar installers, building owners, roofing contractors, surveyors and project teams preparing industrial roofs for solar PV installations.
Our support can include:
Initial project review
A desktop discussion based on photographs, roof plans, survey information and the proposed solar layout.
Roof condition assessment
A site visit to assess visible roof-sheet defects and determine whether a Liquasil repair or coating system may be appropriate.
Project-specific specification
Preparation of a coating specification covering surface preparation, repairs, primers and application requirements.
Roofing contractor support
Introduction to appropriately trained independent contractors where installation support is required.
Inspection and product warranty
Installation inspections can be undertaken where required as part of the product warranty process.
Planning the Solar Layout
Where possible, the proposed panel layout should allow continued access to important parts of the roof, including:
- Gutters and outlets
- Rooflights
- Roof access points
- Movement joints
- Service penetrations
- Areas requiring periodic inspection
- Safe maintenance routes
The current MCS standard also recommends that module layouts provide access for maintenance and emergency services and that consideration is given to fragile roof elements such as rooflights.
Roofing access should therefore be considered during the design stage, not after the panels have been installed.
Prepare the Roof Before Installing the Panels
A commercial solar array should not be used to conceal or postpone an existing roofing problem.
Assessing and preparing the roof first can reduce future disruption, clarify responsibility and help ensure that the roof covering is appropriate for the long-term investment being installed above it.
Liquasil can assess the visible condition of industrial metal roof coverings and provide project-specific recommendations for repair or refurbishment. Where other roof types are involved, we can help identify whether specialist assessment or an alternative roofing solution should be considered.