A cold roof places insulation on the internal side of the supporting roof structure, leaving that structure on the colder side of the insulation layer.
What does this mean on your roof?
Existing flat roofs with this arrangement need particular attention to moisture behaviour. Adding internal insulation is not a simple material choice that can be separated from the rest of the roof.
Existing layers, junctions and indoor conditions jointly influence what happens within the construction and whether moisture can accumulate unseen.
Milieu Centraal advises against insulating flat roofs from inside because of moisture problems. Establish the present assembly and available external approaches before deciding. A finished ceiling can conceal important layers. If the construction is uncertain, request targeted investigation and a supported proposal before another layer makes the existing arrangement harder to inspect or understand.
Frequently asked questions
Does cold roof mean a defective roof?
No. It describes the assembly rather than providing a complete condition assessment.
Can internal insulation proceed without assessment?
A flat roof needs a coordinated assessment; an internal layer can create moisture problems.
Consulted 19 September 2026. Check requirements for your own address and selected system.