Increasingly, the designer wants to achieve a slim roof package, making it different from the traditional structure with a relatively high ventilated cavity. Also, with the renovation of roofs, the thickness of the total package can be a problem. The choice is on a non-ventilated, vapor-tight system with the advantage of a slimmer design.
What is a non-ventilated structure?
A non-ventilated structure is a roof and façade construction with no ventilation or air cavity. Thermal insulation followed by a roof covering system is fitted to the support structure. This produces a single-layer, non-ventilated structure. This concept is highly suited to sloping roofs and façades with zinc. To avoid the formation of condensation the structure must be damp proofed. Internal condensation or condensation resulting from nocturnal temperature drops, do not form in this construction either. This represents a major difference with a traditional cold roof system. When building this structure the preference is for a damp-proof system with a μ.d (or Sd) value of at least 150 meters.
Benefits of a vapor-tight construction
• Considerably more design freedom for architects and developers
• A slim design, because no ventilation cavity is needed
• Easy to handle and therefore time saving during assembly
• High-quality noise damping and insulation
• The roof or façade construction is immediately rain-proof, which reduces construction time
Risks of a vapor-tight construction
In the application of vapor-proof systems, risks are present that may affect the functionality and longevity:
• Mutual seams that are not properly taped
• No rigid substructures
• Making penetrations at a later time, which can cause leaks
• Leaks that may occur through careless installation and detail mistakes