HDSB - Portable Classroom Ventilation Improvements at Various Sites Project Documents Click on the document to view and download A1 – Addendum # 1 A2 – Addendum # 2 A3 – Addendum # 3 A4- Addendum # 4 A5- Addendum # 5 1- RFT 21-113 Portable Classroom Ventilation Improvements – FINAL Do you need help with your construction work?Contact us today Contact Us