GOC2777082-CS - CNS: Roof Replacement

Scope of Work/Overview:
The Federal Records Centre is located at 1700 Inkster Boulevard, in Winnipeg, Manitoba.  The building is currently 49 years old and it has been revealed through a Carbon Neutral Study that the roof has reached its anticipated end of useful life and that a replacement is needed.  Despite the absence of any roof top penetrations or equipment/chattels, the roof is showing signs of wear and deterioration, and leaks have been recently reported.  Several inter-ply blisters, membrane ridging, and end lap slippage were observed as well as areas of granule loss and alligator cracking.  As per the Building Conditions Report (BCR) completed in 2018, the roof was last replaced in 1996, with average condition and recommended replacement in 2021. The intent of this project is to remove and replace existing roofing, which is nearly 5 Ac in size. Replace existing 75mm insulation with 250mm insulation as a minimum to meet or exceed prescriptive NECB requirements and to improve thermal performance. Existing roofing would be removed down to the steel deck. New roofing shall consist of an air / vapor barrier applied to the structure, 250mm polyisocyanurate insulation adhered to the new air barrier membrane, 12mm gypsum protection board and a 2-ply SBS modified bitumen roof membrane. The new roofing R value shall be of 11.6 m2K/W or better. Includes allowance to increase parapet heights to accommodate added insulation. Improve air tightness of the building through the targeted installation of air barrier sealants and membranes at building transition details. Investigate option to include leak detection system for the roof. Results of the CNS to be used to inform the different options developed for this project