How do you choose sandwich panels for a roof and a façade?

The roof carries loads determined by its geometry and location. Wall panels also need checks for wind and the arrangement of supports. One load table cannot cover the whole building. Record planned equipment, openings and possible extensions before selecting a batch, as these may affect the panels and supports on either side of the eaves.

Panel systems are available with PIR, PUR, EPS and mineral wool cores. Compare thermal performance, weight and the fire requirements for the intended assembly. A product’s reaction-to-fire class describes different behaviour from the fire resistance of a complete wall or roof. Obtain documentation for the configuration specified in the design.

Rooms kept at different temperatures may justify different panels within the same building. Design the transitions and tell the installer where each system starts and ends. Select the inside coating for the expected cleaning regime and moisture exposure, and the outside finish for the environment and appearance. Core selection alone leaves those decisions open.

Panel length is the dimension along the piece. Effective cover width is the width each installed panel adds, while overall width may include part of the joint. Thickness alone cannot establish load capacity. For example, ten panels 6 m long with a cover width of 1 m cover 60 m² before cutting. The result applies to those assumed dimensions.

Draw the façade layout around vehicle doors, windows and corners. For the roof, measure along the slope and allow for eaves and ridge details. A long panel can reduce the number of joints but may need larger lifting equipment. A shorter panel may suit refurbishment access while adding a joint that needs to be detailed and priced.

Coordinate the wall-to-roof junction, wall base and the surrounds of openings in detail. Keep insulation and the required seals continuous across these points. The visible flashing is only part of the junction. Check that the seal and support are correct before covering them.

When replacing just the roof or the walls, check the interface with the part that stays. New roof panels may not fit the old eaves flashing. A thicker wall can change the position of the reveal. Measuring these junctions before ordering lets you design any necessary alteration to the neighbouring components.

For an illustrative envelope, allow 140 m² of wall panels at about €29.63/m² and 160 m² of roof panels at about €35.18/m². The panels would cost approximately €4,147.58 for the walls and €5,628.86 for the roof. The total converted before rounding is €9,776.45 excluding VAT. This example excludes accessories, delivery and installation.

Compare options that meet the same requirements in use. More cutting waste can offset a lower wall panel price, and extra supports may raise the cost of a roof. For a heated building, include doors and ventilation when assessing energy use. A difference in panel thickness or price per square metre cannot by itself establish an operating cost saving.

Allow access to roof drainage and penetrations. On the façade, identify areas needing protection from impact and soiling. For both surfaces, plan inspections of coatings and fixings. Use a cleaning method suited to each finish. Coatings with similar colours can require different cleaning and repair methods.

Keep a drawing showing where each panel type is used, together with the junction details. Recheck the design before altering a vehicle door, adding a room or installing rooftop plant. Modular panels make alterations possible, but any new opening or load still needs checking. Coordinating the walls and roof makes it easier to adapt the building while meeting its performance requirements.