There are two basic elements that need to be considered when designing the fixing detail of warm roofs. The wind suction loading is determined by the location of the structure within the UK, the slope of the surrounding land and the structure's overall height. Because of the crushable nature of the insulation material there is an inherent sliding load. The factors that determine the sliding loads are the thickness of the insulation, the slope of the roof and the weight of the roof covering materials. The fixing design will need to address all these factors.