MINUTES OF NELSON/MARLBOROUGH BRANCH TRAINING AND NETWORKING EVENT
Time & Date: 3pm, 27 March 2026
Location: Kenepuru Room -Marlborough District Council 15 Seymour Street, Blenheim and via online
Welcome:
The Branch Executive Paul Guile opened the meeting and welcomed members and guests.
Attendance:
In person: Paul Guile, Gemma Riley, Petra Hajnal, Jeffrey Atkinson, Tara Butler, Hamish Smith, Heydn Richards, Victoria Elvin
Online: Gavin Harding, Jeff Fahrensohn, Sania Shueb
Apologies:
Dhyanom Gala, Brendon Robertson, David Mehlhopt, Julian Morriss, Matthew Campbell, Michelle Bullock, Alysha Hutchison, Anthony Adamson, Hamish Harper, Sam Archer, Phil Eves, Sonya Shah
Previous Minutes: 19/02/2026
Motion: To be approved
Mover: Gemma Riley Seconder: Tara Butler
Matters Arising:
Action: Nil
Decision: Nil
New Members: None
General Business: Nil
Board Representative Update: Nil
Correspondence In/Out: Nil
Building Code Issues:
Action: Nil
Decision: Nil
Guest Presentation(s):
- Victoria Elvin from Kingspan
The presentation from Victoria outlined findings from recent testing into premature roof underlay degradation, identifying UV exposure as the primary cause of failure in synthetic absorbent underlays used in sheds, canopies, and other unlined buildings. Heat was found to have a minor impact on strength, but no synthetic vapour‑permeable underlay was identified as UV‑resistant over long periods.
As a result, Kingspan Thermakraft advised that from 1 July 2025, synthetic absorbent underlays will be limited to use in lined buildings only. Aluminium reinforced foil underlays were recommended for sheds and open buildings, while warehouses may use foil, reinforced foil, or insulated foil systems depending on design.
The presentation also covered condensation in roof designs, noting that condensation is common but manageable with appropriate design. Factors affecting condensation include internal humidity, roof temperature, night sky radiation, roof pitch, ventilation pathways, and building occupancy. Effective roof space ventilation was emphasised as critical, with balanced intake at eaves and exhaust at the ridge required to manage moisture. Skillion roofs were identified as higher risk due to smaller roof cavity volumes and their reliance on well‑designed ventilation detailing. Maintaining adequate internal air change rates and ensuring ceiling air tightness were noted as important measures to reduce condensation risk.
Overall, the presentation reinforced the importance of aligning underlay selection with building use and lining status and ensuring robust roof and internal ventilation design.
The underlay selection website underlayselector.co.nz was also shared.
Next Branch Training and Networking Event: scheduled for 28 May 2026 - TBC
Special thank you to: Marlborough District Council
Paul Guile closed the meeting at 4.15 pm
Petra Hajnal
Nelson/Marlborough Branch Secretary
