This guide is intended to provide building professionals with a methodology for evaluating water leakage through low-sloped roofs. It addresses the service history of a roof, the various components of a roof, and the interaction between these components and adjacent construction. It is not intended as a construction quality control procedure, as specified in Practice D7186, nor as a preconstruction qualification procedure. It is intended for evaluating water leakage through a low-sloped roof.

Qualifications—Use of this guide requires a background as an architect, engineer, roof/waterproofing consultant, roofing contractor, or related profession with an understanding in building construction and the expertise in the design, installation, and maintenance of low-sloped roofs.

Application—The sequential activities described herein are intended to produce an evaluation program, but all activities may not be applicable or necessary for a particular evaluation program. It is the responsibility of the professional using this guide to determine the activities and sequence necessary to perform an appropriate leakage evaluation for a specific low-sloped roof on a building.

Preliminary Assessment—A preliminary assessment may indicate that water leakage problems are limited to a specific element or portion of a low-sloped roof. The evaluation of causes may be limited in scope, and the procedures recommended herein abridged according to the professional judgment of the investigator. A statement stipulating the limits of the investigation should be included in the report.

Expectations—Expectations about the overall effectiveness of an evaluation program must be reasonable, and in proportion to a defined scope of work. This guide is intended to address leakage of a low-sloped roof system, leading to conclusions that can generally be applied to similar or other locations on the roof. Since every possible location is not included in an evaluation program, it is probable that every leak source will not be identified. Leak sources that are localized and unique may remain, and require specific and localized evaluation effort.

This guide is not intended as a design guide. Reference is made to design features of a low-sloped roof only for the purpose of identifying items of interest for consideration in the evaluation process.

This guide does not address leakage through walls not associated with roof construction, fenestration, or leakage below-grade. It is not intended for use with structures designed to retain water, such as pools, fountains, and vegetative roofs.

1.1 This guide describes methods for determining and evaluating causes of water leakage in low-sloped roofs. For this purpose, water penetration is considered leakage and therefore problematic, is causing or is likely to cause premature deterioration of the roof, building or its contents, or is adversely affecting the performance of other components of the building A roof is considered an assembly including the membrane, insulation, vapor retarder (if required), deck, and structural components.

1.1.1 This guide excludes moisture-related problems in roofs caused by condensation.

Note 1—CondensationMoisture-related problems in roof systems may be caused by condensation of humid air originating from within the building and be incorrectly attributed to leakage from rain water. The protocol for an investigation of dampness due to condensation and is complicated, requires special expertise, and is beyond the scope of this guide. For information regarding condensation problems as they relate to roofs, refer to ASTM MNL 18, ASTM MNL 40, and ASHRAE Handbook 2005 Fundamentals.

1.2 Investigative techniques discussed in this guide may be intrusive, disruptive, or destructive. It is the responsibility of the investigator to establish the limitations of use, to anticipate and advise of the destructive nature of some procedures, and to plan for repairing and selective reconstruction as necessary.

1.3 This guide does not address steep-sloped roofs, standing or flat seam metal roofs, or architectural standing seam metal roofs.

1.4 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.