The choice of roofing for an industrial hall depends primarily on the building's purpose and the conditions inside it. Before comparing trapezoidal sheet, sandwich panels or a roof on structural decking, establish whether the hall will be heated, what humidity levels prevail and whether aggressive substances are present. Also check the purlin spacing, loads, and fire and acoustic requirements. For an unheated shelter, a suitably selected trapezoidal sheet may suffice, but in a hall with wet processes an anti-condensation layer alone will not solve the problem. Leave the final decision to the designer.