Adding rooftop solar to an EPS-insulated roof

Consult the as-built records for the complete roof, including its classifications. Check the areas around outlets, parapets and penetrations for moisture, deformation and old repairs. Where records are insufficient, the roofing contractor may need to open up and reseal sample areas. Coordinate reroofing before installing an array that could obstruct later repairs.

Alongside the modules and frames, include any ballast required to prevent movement. Determine its weight and location for this roof. Wind and snow change the forces transmitted to the structure. For a mechanically fixed system, detail the anchorage and each penetration through the waterproofing.

Dividing the total weight by the module area conceals pressure peaks beneath individual feet. Use the dimensions and spacing of the supports and check the load-spreading layers. A pad may protect the membrane from abrasion while spreading little of the force beyond its footprint.

Supports may load the same points for many years. Use the creep data for the actual EPS board and an appropriate limit on deformation as well as its short-term CS(10) value. Indentation can change frame alignment and form depressions in the waterproofing.

CS(10)100 denotes a stress of 100 kPa at 10% deformation in a test. It does not establish that the board can carry 100 kPa permanently. Obtain the relevant sustained-load data. If these are unavailable, complete the assessment before selecting a larger pad or another support detail.

Arrange modules so outlets can be inspected and water can follow the designed falls. Check supports and ballast near outlet sumps in particular. A small local settlement can alter drainage and leave water standing behind a support.

Plan routes from the access hatch to equipment and allow enough room for repairs. The walkway must protect the roof covering and carry the expected loads. A roof previously visited only for occasional drain inspections may need additional provision for regular PV servicing.

Coordinate the electrical installation with the building’s fire strategy and the installation requirements. The reaction-to-fire class of the EPS describes the insulation. To assess the finished roof with PV, check the covering, array layout and necessary protective measures against documentation for the actual configuration.

Check the scope of the roof’s existing classification before relying on it for the added equipment. Coordinate cables, penetrations and plant locations. Establish these constraints before placing the modules on the drawing, as changes later may reduce the space available for the array.

Coordinate the PV designer, structural designer and person responsible for the roof. Confirm warranty conditions and permitted protection layers. Agree storage, including temporary ballast stacks, installation procedures and final inspection. Record the actual EPS board, whether supplied by swisspor, Paneltech, Neotherm, Termo Organika or another manufacturer. Include supports and waterproofing in subsequent inspections.

If the roof covering is to be replaced, roof-integrated photovoltaics are a separate design option. Manufacturers and brands in solar roofing include SolRoof, Electrotile, MDM NT (MyRoof), ML System, SunRoof, Wienerberger Wevolt, Solarstone, Megasol Energie, Autarq and Ennogie.