GOC1824268 - Roof Envelope System Replacement for Outlying Buildings

The scope of work involves completely replacing the roofing systems for the Annex, Small Craft and the Sewage Treatment buildings with a new 2-ply Modified Bitumen insulated roofing system. In addition, the new insulation will be sloped to provide positive drainage to the existing roof drains. This will limit the standing water on the roof and the therefore reduce the potential for leakage. Due to the increase in overall insulation thickness, some modification to the curb heights for mechanical units will be required. It is unlikely that any parapets will have to be extended due to increased insulation thickness. All roof drains will have to be extended with this option. These costs are included within the estimate. Roofs installed to the current National energy Code of Canada (2015) require an overall thermal transmittance of 0.162 W/(m2 K), equivalent to RSI 6.17 or R-35. Therefore, an R35 roof meets the requirements. The addition of a fully adhered vapor barrier will assist in the total performance of the new roof system, including a detailed membrane at all roof wall interfaces. The new roof system will meet and exceed the CSA123.21 roof assemblies for wind uplift.