BUR Section 10: Re-Roofing

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BUR-10.2 Primary Membrance Replacement

1. When considering an existing conventional insulated roofing system for primary membrane replacement the following factors require evaluation:
   1. The effect that the lack of a vapour retarder may have had on the failure of the existing membrane,
   2. The type, condition and thickness of the existing insulation and the amount of moisture that may have infiltrated the insulation (dryness),
   3. The existing roof deck type and its structural integrity if moisture reached the deck, and
   4. The attachment of roofing system components to their existing substrates.
2. When membrane replacement is undertaken, uncorrected defects hidden from view, such as wet insulation or a deteriorated deck, could jeopardize roofing system performance.
3. Wet and damaged insulation shall be removed and replaced with new insulation, to match the existing thickness.
4. When an existing vapour retarder membrane is present, or when the existing insulation is fully adhered to a concrete deck, care must be taken to ensure all wet insulation is located and replaced.
5. Under no circumstance shall a phenolic resin insulation product be left in place or reused.
6. Existing wood fiberboard, mineral fiber/perlite, glass fiber or Stramit primary insulation may be left in place whether or not they are covered by a secondary insulation/cover board.
7. Existing polyisocyanurate, urethane, foam glass, cork, expanded polystyrene, glass fiber less than 38 mm (1.5”) thick and extruded polystyrene primary insulation less than 38mm (1.5”) thick must be removed and replaced, except when covered by a secondary insulation/cover board consisting of wood fiberboard or perlite insulation. Exercise extra caution to ensure that all wet primary insulation is located and replaced when there is a secondary insulation/cover board in place.
8. When the primary membrane is being removed from stramit or glass fiber insulation that have a facer, the condition of the insulation facer after the tear off determines the surface preparation method for the application of the new roof membrane. When re-roofing over stramit the first layer of approved coverboard must be mechanically fastened to the structural joist or deck. If the first layer is fiberboard, then the second layer of approved 12.7mm (1/2″) coverboard may be adhered or mechanically fastened with screws and plates. When thermal upgrading is required, the first layer of the secondary insulation/coverboard may be substituted for/by the upgraded insulation material. Attachment requirements remain the same.
   

   *REVISED 2016-01

9. Regardless of the primary insulation type or the presence of an existing secondary insulation/cover board, in all cases a new secondary insulation/cover board layer meeting ARCA Warranty Certificate application standards is required to provide a consistent substrate for the application of the new roof membrane.
10. Polyurethane Foam Adhesive may NOT be used to adhere insulation or cover board to existing fiberglass insulation, perlite insulation or stramit.
    

    *ADDED 2014-10

BUR-10.4 Protected Membrane Design Re-Roofs

1. A five (5) year Warranty Certificate may be issued for built-up protected membrane design re-roofs when the roof drainage slope is less than 1:50 provided that inorganic felt is used and the field of the completed BUR is either covered with Type 4 primary insulation incorporating drainage channels on its underside or an accepted inorganic drainage mat placed between the primary membrane and the Type 4 insulation.
   

   *ADDED 2010-12