By focusing on turn signals, penetrations and pedestrian traffic, managers can extend the life of the roofs.
Roof systems in institutional and commercial facilities are usually an afterthought for the residents of buildings – until the roof is leaky. Roof leaks are a nuisance to occupants at best, but can often lead to property damage and costly repairs. In fact, water ingress accounts for more than 70 percent of construction conflicts.
For maintenance and engineering managers, roof systems are one of the more demanding components for building maintenance. To make efficient use of the department’s resources, managers can focus their maintenance on three of the most common problems with roofs: blinking, roof penetration and pedestrian traffic. The best way to combat these issues is to conduct regular inspections, extensive repairs, and ongoing prevention.
1. Flash points
Turn signals make up only a small percentage of the total area of a roof, but a technician can often track problems and leak to a flash rather than a field membrane. Wherever a membrane ends, there is a possibility of water infiltration and thus a weak point in the system, especially if the installers have not properly detailed it. The increase in wind is also up to 1.5 times stronger at the edges of the roof and 2.5 times stronger at the corners than on the field, making perimeter lightning and caps more susceptible.
Because of their importance, flashing materials should meet or exceed the life expectancy of the roof. Lightning often connects different moving components, so they should be able to accept thermal and load-related movement, especially when over an expansion joint.
Material selection is important early in the process. For example, prefabricated products and pre-assembled tape products instead of adhesive seams in EPDM membranes can avoid multiple installation steps and human error during installation, says a major roof manufacturer.
Piling up water on flashing seams increases the likelihood of failure. Therefore, technicians should take steps to avoid this whenever possible. You can install edge strips at any 90-degree transitions on the roof. This gradual 45 degree transition instead of the abrupt 90 degree transition reduces the risk of failure in these areas and draws water away from the lightning bolts.
To further reduce pond formation at flashing seams, technicians should build crickets or water diverters around mechanical curbs to aid drainage. Vertical lightning bolts should typically extend at least 8 inches above the roof. Installing a PVC condensate line to move water from the rooftop HVAC system to the nearest drain is a simple and inexpensive solution to reducing pond formation. Technicians should also keep the roof drains free and functional.
During routine inspections, technicians should identify open seams, punctures, discoloration, and sagging membranes on vertical curbs. Membrane bridging usually occurs when the membrane separates from the vertically rising wall, parapet or curb. The bridging stresses the material, which can lead to cracks and tears. Technicians should preventively touch up the area until the next roof replacement.
For metal parts such as counter flashes, drip strips, parapets, and gravel stoppers, technicians can check: loose, missing, or bent fasteners; bent, corroded or missing sheet metal; and fancy, crazy or open sealing joints. Most facing issues should be obvious even to those unfamiliar with roofing systems. According to FM Global, technicians can check the tackle to see if they can withstand the rise in winds by pulling out the bottom edge. If it feels loose, it can be reattached relatively inexpensively using suitable weatherproof fasteners with washers.
Lightning should also be checked annually or after major weather events. When parts of the roof are opened, technicians should not ignore other discovered problems such as rotten wood nailers, corroded fasteners, and deteriorated insulation. If repairs are required, technicians must ensure that they are correctly detailed and use materials that are compatible with the roof type. Many studies show that following the manufacturer’s recommended inspection and repair schedule results in longer roof life and overall lower roof costs. Keeping insulation dry and in good condition is especially important for the lowest cost, according to FM Global.
2. Roof penetrations
Flashing problems are not just limited to the roof perimeter. They can also occur in roof penetrations. Many such penetrations will be noticeable, such as near plumbing, skylights, and mechanical equipment. Technicians must also ensure that lightning strikes at smaller penetrations, e.g. B. on pipes, stair supports and other less obvious places to be detected and checked for the ingress of water. Prefabricated veneers such as pipe seals, sealant pockets and corner veneers are common solutions for such problems and are immediately ready for installation, says a large roofing manufacturer.
While it is easy to blame the roof system for problems related to penetrations, it may not be the failure of the roof that causes a leak. Deteriorated or bent mechanical curbs can leave openings for water to enter. Deteriorated masonry, failed passage veneers and sealing compounds on a rising wall over a roof system offer further possibilities for water penetration. Heavy rains can potentially get over shallow doorsteps and enter penthouse rooms.
Technicians must check the openings in electrical connection boxes. Even the smallest and seemingly insignificant openings allow water to get under the roof system even though the roof cladding is doing its job. When installing new penetrations into a roof, technicians must ensure that they are properly detailed and accepted by the roof manufacturer if the system is still under warranty.
3. Pedestrian traffic
Roof issues related to pedestrian traffic are mainly related to maintenance and repair personnel who must have access to roof equipment. You could use tools and equipment that could accidentally puncture, cut, scratch, or otherwise damage the roofing membrane.
Internal personnel should report damage to the membrane during routine work and after maintenance projects that involve outside contractors. In general, managers should restrict access to the roof to authorized personnel and be aware that the membrane manufacturer may have restrictions on access in cold weather.
The best way to limit the impact of traffic on the roof is to install paving stones or treads over the roof surface. To increase the likelihood of authorized visitors using paths, they should be the most direct and logical path to any rooftop device.
For work near unprotected edges that is infrequent and temporary – such as replacing filters or cleaning roof drains – personnel must wear a Personal Fall Protection System (PFAS) within 6 feet of the edge of the roof, as per an approved safety plan Anchored or protected by a guardrail system per OSHA 29 CFR 1910 Subsection D. For work 6 to 15 feet from the edge of the roof, either a PFAS or a designated area with warning lines must be used. With these regulations in mind, pathways should not be installed within 15 feet of the edge of the roof to ensure a safe driving distance from the unprotected edge. Guardrails should be installed in locations where installation over 15 feet is not possible.
While paving stones protect the roofing membrane from pedestrian traffic, they can also be responsible for masking drainage problems and covering up deterioration, vegetative growth, and debris. Insulated composite pavers combine insulation properties with pedestrian protection. If the water under the patches does not drain properly, it will grow and deteriorate, reducing the effectiveness of the insulation.
Managers should perform wind elevator calculations before approving the installation of concrete paving stones to determine the required parapet height per ANSI / SPRI RP-4. Ballast may not be allowed in some building heights and locations. In these cases, managers should indicate adherent walking surfaces instead of concrete paving stones. Managers should also evaluate the roof’s structural capacity to determine whether it can adequately support the ballast weight prior to installation.
Roof systems degrade over time and need to be repaired as they near the end of their life. However, if properly maintained, they can exceed expectations. It’s good practice for technicians to walk on a roof a few times a year and even run an annual maintenance program with a qualified roofer, says one major roofing manufacturer, adding that a roof with a proactive maintenance program will last longer than a roof with a reactive maintenance program.
When a roof is nearing the end of its useful life, an assessment by a roofing consultant can estimate how long it will be before a roof replacement is required, and repairs are recommended by then. Monitoring and documenting the frequency of leaks and repair costs can also help managers determine when to replace them.
Erin Falvey is a project engineer at Facility Engineering Associates. Falvey holds a degree in civil engineering from the University of Virginia and works to provide engineering solutions to customers to maximize the life of physical assets through repair and restoration projects in roofing, outbuildings, parking garages, and fall protection.