It is true that a sandwich panel installs quickly, but the source of that speed is not the panel itself. A panel arrives finished from the factory; the work left on site is lifting, aligning and fixing. Five decisions set how long that work takes, and all five are made before the panel reaches the ground.

1. Panel length: the number of joints

In the standard range, one-piece lengths reach 15.5 metres. A panel that crosses the flow of the roof in one piece removes both an installation step and a lap detail.

A lap is not only labour: every joint is a sealing point, and every sealing point adds a line to the annual maintenance list. In the EXO range the length is limited to 12 metres; on short spans that difference is not felt, on long flows it is.

2. Cover width: pieces per square metre

The cover width is 1000 mm, so each panel closes one metre of width. Cold room panels also come in 1050, 1095 and 1200 mm, and cover the same surface with fewer pieces.

How many panels will arrive is not estimated but calculated: the panel area calculator gives the count and the total area surface by surface. That number is the same number for the order and for the installation programme.

3. The screw system: seen and unseen

On an exposed-fix wall system the screw passes through the face of the panel; installation is quick and the screw heads are visible. On a concealed-fix system the screw stays inside the interlock; the surface comes out clean, installation is a little slower and more sensitive to alignment.

The decision is made on visibility: concealed fixings where the elevation is the face of the building, exposed fixings where it stays in the background. The fastener itself is also selected, because a screw of the wrong length either crushes the core or fails to compress the gasket.

4. Delivery order: the panel nobody can find

What slows an installation most is often not the panel but the order of the pallets. A vehicle loaded in the wrong order leaves the team restacking pallets, and that work is done with a crane.

The number of vehicles and the layout are worked out in advance: the loading quantities calculator gives the count per vehicle by product and thickness, and prints the result.

5. The joint detail: the drawing nobody argues about on site

Ridges, valleys, parapets, corners and eaves are where installation slows down, and every one of them has a drawing. When a detail starts being drawn on site, installation stops.

All the joint details are in the Library section; the notes on installation, unloading and lifting are on the installation page.

Three things that slow installation

  • Poor stacking: a pallet standing on uneven ground crushes the panel edge, and a crushed edge does not hold alignment
  • Protective film left on: film left in the sun bonds to the steel, and removing it later takes longer than the installation
  • Pitch error: the minimum pitch for a sandwich roof panel is 7%, and below that the joint detail changes and the work has to be planned again

Speed does not mean cheap

When installation time falls, labour and crane hire fall with it and the building is handed over earlier. But a fast installation does not justify skipping a detail: the cost of a joint that opens later is greater than the two days gained.