Whether a building has a steep-slope, low-slope, or even a flat roof, the roof is the first line of defense against the elements. Routine preventive roof maintenance can protect buildings from damaging weather, extend the life of the roof system, and decrease building life-cycle costs.
The untrained eye can spot problems on the roof surface. Simple visual inspection can reveal obvious signs of problems. The following paragraphs discuss general items that should be checked on low-slope, flat, and steep-slope roofs.
Roofs should be checked for debris and sharp items that could damage the roof system. Sharp items should be removed from the roof immediately. Trees that overhang a roof should be trimmed or cut back to reduce the potential for tree debris on the roof.
Ensure drain covers are properly installed to prevent debris from clogging drain lines, and make sure scupper openings are clear of debris. If the roof has gutters and downspouts, they should be inspected and, if clogged, the debris should immediately be removed. When inspecting gutters, check for sagging, which will prevent water from draining properly.
Coatings on the roof membrane and flashings should also be checked to ensure that they have not de-bonded from the base material or deteriorated to the point of exposing the roof.
Specific to low-slope and flat roofs, look for cracks, cuts, punctures, and other types of openings in the top layer of the roof membrane and flashings. Inspect seams and laps; they should be tight with no visible openings. Look for blistered (bubbled) or delaminated areas of the membrane. Flashings should be well adhered to the back-up material.
If roof maintenance has been deferred for an extended period of time, vegetation may grow on the roof and damage the membrane and flashings and create openings in the roof system.
Check for cracked or missing flexible sealant (caulk) at walls and around penetrations. Pitch pockets should be filled with pourable sealer to the top of the pocket with no cracks in the sealer. Perimeter sheet metal (cap flashing) should be secured to the substrate. Look for loose or missing fasteners.
On ballasted systems, the gravel ballast should be evenly distributed. Pay close attention to high-traffic areas, drainage areas, around roof penetrations and mechanical equipment, and at roof transition points.
If the roof is a shingle system, check for missing or damaged shingles. Damage includes splitting or cracking of the shingles and curling of the edges and loss of aggregate surfacing on asphalt shingles. The exposed flashings at penetrations should be checked to ensure that they are tight against the building element that penetrates the roof surface. Associated metal components, such as ridge vents and hot stacks, should be checked for openings, damage, and surface corrosion.
With metal roof systems, the roof should be checked for openings in the roof at panel seams, loose or missing fasteners, damaged panels, ponding water on the panels, and metal corrosion.
Repair work should be performed by qualified roofing personnel and in accordance with the guidelines established by the roof system manufacturer and the National Roofing Contractors Association (NRCA).
Daniel L. Watkins is an associate with Fairfax, VA-based Facility Engineering Associates PC (www.feapc.com) and specializes in repair and restoration consulting.