Most roofs are not watertight all the time. Roofing systems, both low-sloped (flat) and pitched, will most likely eventually spring a leak, even with the proper recommended maintenance and inspections. But what about newly installed low-sloped roofs, can one expect those to be watertight? Typically, on a newly constructed building, any minor leaks that turn up during construction can be dealt with immediately by the installer. Also, newly installed roofs on new and old buildings will undergo inspections and sometimes specified testing of seams and components for issuance of the manufacturer’s and installer’s warranty of water tightness for a specified period of time. However, ensuring that your newly installed roof is absolutely watertight becomes more critical if it is being covered by rock ballast or a landscaped greenspace or if the roof protects valuable artwork or irreplaceable property. Determining the location, origin, and extent of wet substrates is also critical for existing buildings when trying to determine if repair or complete replacement is more appropriate.
In the article, Everything Leaks: Testing to ensure watertightness at the outset, Ronald J. Ray, RA, CCS, CCA, CSI, AIA examines some the methods of roof testing, emphasizing their effectiveness and limitations.
Mr. Ray rightly points out that one of the time-honored methods for leak testing, flooding a roof, either non-scientifically or according to ASTM D5957, Standard Guide for Flood Testing Horizontal Waterproof Installations, is generally inappropriate. The National Roofing Contractors Association (NRCA) does not recommend flood-testing of new roof systems for identifying potential leak sources since “roof systems are designed to resist the passage of water with a minimal amount of hydrostatic pressure (i.e. flowing water), while waterproofing systems are designed to prevent the passage of water under hydrostatic pressure (i.e. standing water).” In addition, flooding does not test many of the key components such as flashings, terminations, and caps. There can also be structural considerations with the weight of the depth of water created on a large expanses of low-sloping roof. However, flood testing small areas is often a good diagnostic tool for forcing potential membrane issues to appear and to observe leak pathways.
With today’s technologies there are more reliable, practical, and precise electronic leak testing methods available for diagnosing and locating potential or actual roof leaks, with each being more appropriate under certain circumstances. The article examines:
Other factors to be considered when choosing a system include the size of the roof, the relative costs of each test, the availability of skilled professionals, and that other less technological, yet still effective methods may be available.
CCA generally recommends taking an incremental approach, starting with interior and exterior observations with non-destructive moisture meters and infrared cameras in the hands of trained professionals with years of experience in diagnosing roofing issues. However, particularly with newer roofs, the technological methods discussed above are often clearly appropriate to identify potential areas of concern.
Continue reading this informative article by Mr. Ray to learn more.