Ventilation duct — roof penetration (GS PIR D)

Junction function

Ventilation duct through roof = penetration of a vent stack / HVAC duct / process duct through the roof panel. A critical detail for:

• Rainwater tightness — water must not penetrate through the duct collar.
• Structural stability — the duct may be heavy (HVAC counterweight) and must be securely fastened.

Critical installation aspects

• Location in the central field of the panel — min. 300 mm from the panel edge; placement closer to the edge compromises the joint and causes leaks.
• Vent stack roof base = a prefabricated unit matched to the trapezoidal profile; its flange is sealed with butyl tape around the entire perimeter.
• OB-28 + custom flashing surround the base.
• Opening in the panel = cut with a diamond saw; protect edges with PUR foam to prevent water ingress into the PIR core.
• Ventilation compensation — the vent stack requires airflow; install a backdraft damper if required.
• Thermal bridge = steel vent stack ψ ≈ 0.3 W/K — cover with external insulation (insulating jacket).

Documentation

Technical Catalogue insPIRe S/U + GS PIR D (Gór-Stal 2025), page 106 — Ventilation duct — roof penetration. Scale 1:5.

Components in this junction