A New Sustainable Roofing Certification for FM Professionals - Free Webcast, View Now
Regular Roofing Maintenance: When to Inspect the Roof
By Karen Warseck - August 2010 - Roofing
You are aging. Don't deny it. Every day takes its toll on you little by little. Because nobody wants to get old, we do things to delay the inevitable — we eat right (some of the time), exercise regularly (or occasionally) and see our doctors for check-ups to be sure that we have no serious problems. After all, if we take care of the small stuff, it will delay the more serious issues that can shorten our lives.
A roof is the same way. Everyday exposure to sun, rain, air conditioning repair people, and other wear and tear slowly ages the roof membrane until the service life ends. Every extra year one can eke out of the roof is that much more money that can be saved for other purposes.
A roof doesn't need good food or proper exercise. But a roof does need regular check-ups in the form of regular inspections and prompt repairs.
What benefit is there in spending money every year to maintain the roof? Studies have shown that a roof that is not regularly maintained will only last about half of its expected service life.
But, you say, "That's why I have a warranty." Don't assume that a warranty will help. Almost all manufacturers of roofing materials state specifically in their warranty that the warranty is void if the roof is not maintained. If you can't show that the roof has been maintained, you will not have a case when you try to make a claim on a supposed warranty issue.
Experienced facility managers know that a roof should be inspected at least twice a year to keep the roof alive as long as possible and to maintain the warranty. But many don't know what to look for, so they either hire someone else to do it or it just doesn't get done. Depending on the depth and complexity of the inspection, the inspector can be the building staff, an architect or engineer who specializes in roof consulting, or a competent roofing contractor. The inspection can entail anything from looking at the roof while walking to repair an A/C unit all the way to a formal inspection with a moisture survey.
When to Inspect the Roof?
You want to have the inspections done once before the season with the most severe weather and once after. In the northern climes, the severe weather is winter where the cold, storms and precipitation contributes more to the demise of the roof. However, where hot weather rules, summer is the severe season. The solar UV radiation is higher, and the roof is subjected to high heat and to thermal shock due to sudden cooling during summer rains. So you want to check the roof before the severe season to prepare the roof for its ordeal to come and once after it has weathered the season to repair any problems that happened during.
Periodically, a formal moisture survey should be done in addition to the normal visual survey. There are three major types of moisture survey systems used, none of which actually measures water. All of them measure properties of the roof materials that change when there is water present.
- An infrared scan measures the amount of heat retained or lost through the insulation. Wet insulation transmits heat better than dry materials. Thus, the infrared camera will pick up the higher levels of heat radiated by wet materials.
- Nuclear isotopic meters work by sending hydrogen ions into the roof system and counting the number that bounce back. Because water has two hydrogen ions in every molecule, the number of ions counted increases significantly when water is present in the roof.
- Electrical capacitance and resistance meters measure the ability of roof materials to conduct electricity. They work on the principle that wet materials conduct electricity better than dry ones do.
Each of these testing methods has limitations that need to be discussed with a roofing expert to determine their applicability to a particular roof before they are used. It is worthwhile to have a formal moisture survey done at least once every five years. If a roof is found to be in marginal condition at any time, a survey should be used at that point to help formulate a course of action.