The split-insulated roof assembly must be carefully designed to ensure the interior insulation does not result in condensation risk at the roof sheathing.

Where possible, split-insulated roofs should be designed using hygrothermal design software that considers the climate and interior conditions that the assembly will be exposed to.

Multiple insulation layers should be offset, such that board edges of different layers do not align one atop one another. This ensures there is a continuous uniform layer of insulation. This roof relies on the secure attachment of the rigid insulation for the adequate wind uplift resistance of all assembly components.

Insulation attachment methods include roofing adhesives and/or pin fasteners through the insulation to the roof framing.

Care must be taken when using mechanical attachment methods. The recommend approach is the use of adhesives with rigid mineral wool.