Ask for the complete build-up
Request drawings showing insulation, structural members, membranes, cavities, finishes and junctions. A product’s insulation value does not include every thermal bridge or air leak in an assembled room. Have the proposed system checked for your intended use.
Keep the room dry as well as warm
Rain resistance, ground moisture, indoor moisture and ventilation are different issues. Follow a coherent condensation-risk and moisture-control design. Do not copy the position of a vapour-control layer from a build using a different construction system.
Plan for summer
Large glazed elevations can bring unwanted heat and glare. Consider orientation, shading, opening windows and controllable ventilation alongside winter heating. For an office, place the desk to manage reflections on the screen.
Check before covering up
Photograph insulation joints and service penetrations. Inspect for gaps and damaged membranes before linings go on. Ask for installation guidance from the chosen system manufacturer and resolve inconsistent details with the designer.