The temperature at the vapor retarder shall be warmer than the dew point temperature for the vapor retarder to perform its designed function. When sandwich type construction is specified, the underlying layer of rigid board shall not be included in the R-value calculations for deriving dew point location. Also, the underlying layer of rigid board shall not be made from hydroscopic materials that may degrade from moisture.

Vapor Retarder Continuity from Roof Plane through Flashings
Vapor retarders shall extend continuously and evenly throughout the roof plane so as to provide a complete seal against the intrusion of moist air from the building interior. Vapor retarder wall penetrations and perimeters shall be sealed and flashed per the "Flashing Details" section.

Prevention of Asphalt Drippage
When vapor retarders are installed over nailable roof decks with joints between individual deck components, install a UK5 KraftFelt or adhere cut strips of the specified Fields base sheet with M300 RubrMastic over the joints so as to prevent the driping of asphalt into the building's interior.

Temporary Roofs
If installation of the roof system is required during unsuitable weather, or before completion of wood blocking, curbs, penetrations, or the erection of walls, a temporary roof may be installed. A temporary roof allows for the delayed installation of the roof system until more suitable weather, or until other trades can complete their projects. A temporary roof shall be designed and installed in the same way as a vapor retarder, and may also become a vapor retarder.

If roof insulation is installed under the temporary roof, the insulation shall be inspected for wet or damaged areas, so that such areas may be removed and replaced prior to installation of the Fields BUR membrane.

When a temporary roof is specified as a vapor retarder, precaution shall be exercised in protecting the temporary roof from other construction tradesmen. Damage to the temporary roof may impair its effectiveness as a vapor retarder. If the vapor retarder is installed as a temporary roof during construction, the vapor retarder shall be examined, and if necessary, repaired to ensure watertight integrity prior to installation of the remainder of the roof system.

Compatibility
Fields vapor retarders are constructed with ambient or hot applied asphalt, which may not be compatible with certain types of insulation. Insulation manufacturers and Fields shall be consulted for compatibility with the specified Fields asphalt.

Vapor Retarder and Temporary Roof Attachment
Fields asphalt shall be specified to adhere vapor retarders and temporary roofs to non-nailable roof decks.

Insulation Attachment
Insulation installed over vapor retarders and temporary roofs shall be adhered into the specified Fields asphalt.

Roof Assemblies over High Humidity Buildings
The designer shall specify the roof deck, vapor retarder, and rigid insulation over high humidity buildings such as those with swimming pools, laundry facilities, paper mills, and bottling plants. In these types of environments, there is substantial upward vapor drive, and the potential exists for extreme amounts of moisture accumulation within the roof assembly. If an effective vapor retarder is not included at the proper location in the roof assembly, so that the retarder is warmer than the dew point, condensation will cause damage from the moisture retained in the roof assembly.

Weather Protection during Installation
Water cut-offs are permanent Fields BUR reinforcing sheets adhered during construction of the roof system so as to prevent lateral water movement within the insulation, and so as to isolate sections of the roof system during construction so as to limit possible water intrusion.

Tie-offs are temporary Fields BUR reinforcing sheets adhered to seal the roof system from moisture intrusion during construction. Tie-offs and temporary flashings are installed at roof openings and exposed flashings prior to the end of each day so as to protect the roof system from the entry of moisture. Tie-offs shall be removed prior to continuing installation of the roof system.

Roof Drains & Scuppers
Roof drains and scuppers installed during the construction phase shall be in a drainable, functioning condition by the end of each day.

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