The Top 10 Most Common Roof Restoration Mistakes
3) POOR INSTALLATION AND UNSATISFACTORY WORKMANSHIP
Torch-applied mod bit system performance can be compromised if crews do not relax the sheets prior to installation. Material preparation is important to a quality installation. CARE. notes, “Sheets installed that have not relaxed or are installed when ambient conditions such as temperature are not right can result in wrinkles, leaks, fish mouths, contraction of sheets, or blisters.” Be sure that the contractor and crew you’ve hired are educated in proper installation techniques specific to the roof they are installing.
4) LACK OF MAINTENANCE
There are many reasons not to neglect the roof – including financial and business continuity reasons. Being wise to problems can prevent their escalation. “The problem in roofing is a lack of education on all levels. But if the owner of the property is better educated, the whole industry does better and less problems [occur],” explains Chris Mooney, GAFMC/CARE national training manager, CARE, Wayne, NJ. Specific levels of maintenance are required to prevent voiding the warranty. “Perform routine inspections. You don’t have to know a lot about roofing,” Pierce explains. “Things like ponding water, a piece of slipped base flashing, pitch pockets that haven’t been filled – those should be obvious whether you know a lot about roofing or not.” Addressing minor problems before they escalate maximizes roof life as well as minimizes headaches and expense.
5) PONDING WATER
“Another common problem across all roof types is what I call ‘incidental ponding water.’ If we move the water off the roof, the roof has a really good chance of performing the way it should,” notes Pierce. During the design of a dead-level roof, slope should be added with tapered insulation or crickets. “If we don’t take proactive measures when we’re actually designing the roof, then we’re building in ponding water,” she stresses.
UV rays compounded by ponding water can have adverse effects on BUR and asphalt-based mod bit roofs. During installation of hot bituminous systems, CARE warns that improper mopping can produce voids in the membrane, block drains, and result in ponding water as well as void the warranty.
Pierce cautions that before roof repairs are hastily made, the source of the ponding water should be investigated. HVAC units without condensate drain lines could be the culprit. Always inspect thoroughly before making a repair. Check drains to make sure they are free of dirt, silt, and debris.
6) PUNCTURES AND THE ADDITION OF PENETRATIONS POST-INSTALLATION
For all owners, but especially those with single-ply or spray polyurethane foam (SPF) roof systems, damage from foot traffic can be problematic. “Punctures are something on high-traffic areas that can be a problem,” says Harriman of single-ply systems. “One of the things we like to do is add walkway paths or extra sacrificial layers of membrane.”
CARE notes abuse of the finished roof as one of the nine most common problems plaguing single-ply systems, stating, “Heavy construction traffic can cause scrapes/cuts in the membrane and damage to the underlying substrate. In addition to leaks, this can cause premature problems with the roof membrane and may void the guarantee.” Limit traffic and conduct cursory inspections after tradespeople have been on the roof.
All roof systems’ performance is compromised when new equipment and penetrations are added to an existing roof, unless proper precautions are taken. When penetrations are added and deleted from a metal roof, the results can be disastrous. “You are sometimes left with a compromise and a lot of caulking and sealants. Metal roofs move a lot. There is a lot of expansion and contraction, and if you are left to deal with caulking, you’re probably going to have problems eventually,” Harriman warns.
The installation of hot bituminous and torch-applied mod bit systems requires strict adherence to safety procedures. Overheating asphalt can result in burns, and fires in the kettle and on the roof, CARE warns. In torch-applied mod bit applications, fire extinguishers should be present and MRCA CERTA program guidelines should be followed.
During installation, odors from cold-applied mod bit systems can cause discomfort and alleged illness among building occupants. Outside air intakes should be covered in roofing areas, recommends CARE.
8) IMPROPER REPAIRS
Using materials that are not intended for application on specific roof types can result in permanent damage to the roof. “One of the most common problems we see with metal roofs is improper repair. People go up with caulking and plastic roof cement and improper materials that are in no way intended for that purpose,” Harriman says. “You can make a small problem worse through that improper repair.”
Pierce agrees. However, this problem isn’t exclusive to metal roofs. “On a built-up or modified roof, that five-gallon bucket of plastic cement can solve a lot of problems. But if I take that five-gallon bucket of plastic cement up on a single-ply membrane, I may actually damage the membrane itself,” she says. Follow the manufacturer’s instructions for proper use and take note of repair products with a shelf life.
Single-ply roof types are each unique. “If you walk out onto an EPDM roof today, one of the first things you’re going to look for is evidence of shrinkage,” Harriman notes. “The two most common things I see, especially on ballasted membranes, are pulling of the flashings (which is due to shrinkage of the field membrane) or you could have deterioration – surface crazing and cracking of uncured membrane, commonly used at perimeter and penetration flashing
Blistering, ridging, splitting, and surface erosion are symptomatic with BUR, and can eventually lead to bigger problems. While blisters are not always worth fixing, one of significant size should be addressed. According to CARE, inadequate attachment of hot bituminous roof systems due to asphalt heated to an improper temperature can cause blistering, along with the slipping of felts, and accelerated aging. Bad interply integrity and dry laps can also result in the appearance of blisters.
Voids and holidays can be problematic in the application of torch-applied modified bitumens. “If the membrane is not torched properly, it will result in delamination, slippage, and blisters,” the CARE CD-Rom reports. Moisture and air trapped in modified bitumen roofs can vaporize, causing a blister. “Many times it’s non-threatening, unless it’s affecting the lap area and then it probably needs to be repaired,” says Harriman.
With cold-applied mod bit systems, the entire membrane should be installed in the same application (i.e., scheduled around work breaks and/or holidays). CARE pinpoints the consequences of improper sequencing of work as contamination and poor adhesion between the cap sheet and base ply: ultimately, blisters, delamination, leaks, and voids.
During the installation of spray polyurethane foam systems, recovering over a wet substrate can result in severe blistering and delamination, notes Harriman.
Ensuring a quality installation, providing the roof with consistent maintenance, and the early detection of problems through routine inspections can help maximize roof life. As the roof ages, the likelihood of problems increases. However, it is how these problems are addressed that will determine the fate and future of your roof system.
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