Calculate across the full area
A layer weighing 6 kg/m² adds about 6,000 kg over 1,000 m². At 12 kg/m², that becomes 12,000 kg. These are calculation examples, not product values or structural approval. Moisture, fixings, PV and any ballast must also be considered.
Thickness is only part of the picture
Materials differ in density, strength and moisture behaviour. Compare declared surface mass at a known material condition. A lighter board may require a different support or fixing arrangement. Thin does not automatically mean suitable for every roof.
Installation loads count too
A pallet creates a concentrated load during installation. Plan material storage locations, distribution and lifting equipment. Ask the responsible structural engineer to assess available capacity; product advice cannot replace that assessment.
Ask about kg/m², total added mass and temporary installation loads.
Roof load example
Added dry mass only. Not a structural assessment.
Technical background: deu.sika.com ↗
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