In Issue #50 (May 2006), I pointed out that the best and most cost-effective way to conserve energy was to maintain the roof system so that the roof insulation remains dry.
I also pointed out that visual surveys were the best way to do this, and that the roofing industry recommends a minimum of two walkovers per year (one in the spring, and the other in autumn before the bad weather sets in). In addition, inspections should be made after severe storms and after construction activity on the roof.
Using Check Sheets
Years ago, Ed McConnell, a faculty member of The Better Understanding of Roof Systems Institute (BURSI) and later on The Roofing Industry Educational Institute (RIEI), used to tell his students about his experiences as a WWII pilot in the Pacific Theater. He related that, one beautiful morning, he lifted his bomber from the runway and observed the lush verdant scenery of tropical islands contrasted with the deep blue of the Pacific Ocean. He turned to his co-pilot and asked how much fuel had been put on board. “Fuel?”
Ed turned the aircraft around and headed back to the runway, barely making it. He swore he would never skip his preflight check sheets again, no matter how much experience he had.
That advice is applicable to roof check sheets as well. Generally, they are organized into about seven sections. The first section includes general building information such as street address, roof sector (most buildings will have more than one roof level or system), the name of the building owner or facility manager, and the like.
A historical section should follow this building information. Commonly, that history is part of a separate, appended file. This historical file is quite detailed, and generally will not be needed during the visual survey unless analysis of discovered problems is desired. However, a roof plan that shows previous repairs and roof features should be available during the survey.
The second section guides the user to walk around the building’s perimeter. An inspector can see water stains on the walls
, evidence of efflorescence (salt deposits) from water migration, bent or missing fascia metal
, wall cracks, and other things that may explain why the roof is having problems.
The third section takes the user inside the building where walls, columns, and other structural elements can be observed. Heavy piping should never be suspended from the roof deck. Even suspended ceilings should be supported by purlins, not the deck. Roof drains should have under-deck clamping rings to keep the drain from shifting positions. The inspector might need to bring along a flashlight and remove lay-in panels in order to look at the bottom side of the deck. Fasteners should be visible, and (hopefully) there will be no signs of severe rusting or deck damage.
While completing section three, the inspector should interview building personnel that work in that area of the facility. There is no more powerful leak detection method than asking, “Where are the leaks?” These should be located on a roof plan so that, when an inspector gets up on the roof, he/she can check these areas for damage.
You are now ready to go up on the rooftop. Section four, if used, should be reserved for a general overview of the rooftop. Photographs showing ponded areas and piles of debris, as well as general roof features may accompany this. For example, if ballast is displaced due to foot traffic, you might want to remove ballast from the affected areas and replace it with walk pads.
The rooftop survey then generally begins with a perimeter walk-around (section five). Refer to the exterior walk-around notes to see if you can correlate water stains with visible damage or missing roof components. Many components, such as gravel-stop metal on BUR systems, are not nearly as durable as the roof system itself. In addition, these may be excluded from the roof warranty, so the owner needs to repair the splits that occur in the stripping plies before the problems become severe. If the roof drains into a gutter or scupper, remove the trash (soda and beer cans, empty refrigerant containers, tennis balls, and anything else that might interfere with proper drainage). Internal roof drains need to have trash and vegetation removed from the screens; if the screens are missing, new screens should be installed. If it appears the drains are not functioning (which you may be able to tell from stains or discoloration patterns on the roof), water-test them.
The perimeter walk includes a close look at wall flashings and copings. As with gravel stop metal, these are high stress points and are likely to cause problems well before the membrane does.
Section six directs us to the typical equipment features found on most every roof. They are generally of two types: Curbed units in which there is a base flashing and counter-flashing, and roof penetrations in which a “pitch-pocket” or “witches hat” (flexible boot) are used. Curbed flashings, when installed properly, are quite durable unless the mechanical unit vibrates severely enough to fatigue the materials, it is abused by HVAC mechanics, or it exhausts chemicals or oils that degrade the flashing.
On the other hand, the old style pitch-pan (which is a low, bottomless pan) requires service very frequently. With BUR systems, the filler was commonly a couple of inches of mortar, followed by a pouring of hot bitumen or application of asphalt mastic. The filler material shrinks with time; when not refilled, it acts like a reservoir of water which drips into the building for days after the rain ends. The single-ply industry has brought us elastomeric pourable sealers, which are far more durable. However, the industry still promotes “ban the pan,” replacing these low problematic pans with curbed and properly flashed curbs whenever possible.
Section seven is the membrane itself. This section on the check sheets differs depending upon the roof system in place. The Single Ply Roofing Industry (SPRI), Asphalt Roofing Manufacturers Association (ARMA), and National Roofing Contractors Association (NRCA) have provided excellent information on repairs for each type. The Spray Polyurethane Foam Alliance (SPFA) also has excellent information on how to inspect spray-foam roofs. It would always be a good idea to review the historical files on the roof before conducting section seven. This will hopefully reveal what the generic type of membrane is in place (bituminous, mod bit, PVC, EPDM, SPF, copolymer, etc.), as well as warranty information. It is possible the defects you discover are covered under the warranty, and if you try to repair the roof without authorization from the guarantor, the warranty might be voided. Warranties almost always cover defective materials and normal weathering, but usually exclude abuse and neglect. Hopefully, the historical roofing file will have a copy of the warranty, defining your obligations as well as those of the supplier.
The attached inspection forms may help you get started with your inspection program. They are under development, with specific forms planned eventually for each generic type. Hopefully in the future the forms will incorporate input from trade associations such as SPRI, NRCA, ARMA, and SPFA, as well as from individual material manufacturers and suppliers.
Next month, I will discuss the historical roofing file and give you a starting point for that as well.
Asphalt Roofing Manufacturers Association www.asphaltroofing.org
Roof Coatings Manufacturers Association www.roofcoatings.org
Roof Consultants Institute www.rci-online.org
National Roofing Contractors Association www.nrca.net
Spray Polyurethane Foam Alliance www.sprayfoam.org