Roofs, like all other components of the building envelope, need inspections on a routine basis. We would like to offer some general direction to help building owners and facility managers perform routine roof inspections.
zumBrunnen has found that it is practical to budget a capital expense on a 5-year cycle for roofing system tune-ups, minor repairs, and maintenance. We generally recommend budgeting between $0.05 and $0.15 per gross square foot of roof surface. Routine roof inspections by a qualified roofing contractor and associated minor repairs and tune-ups will extend the lifetime of your roofing system and help avoid system failure.
Common issues to look for on your roofs:
Built-Up Roofs
- Loss of felt surfacing, gravel, aluminum coating, or asphalt surfacing
- Felt erosion, loss of plies
- Membrane aging, alligatoring, and brittleness
- Membrane damage, punctures, or cuts
- Membrane defects, blisters (especially broken blisters), splits, ridges. Blisters are spongy spots that are a result of moisture trapped between the felt plies, which can shorten the life of the roof membrane.
- Flashings aging, splits, open laps, or slippage
- Poorly sealed flashing terminations
- Under-filled pitch pans at penetrations
- Clogged or restricted drainage
- Debris, sharp objects on roof
- Chemical exhaust, particularly oil and solvents (from kitchen vents)
- Collapsed, wet, or damaged roof insulation
- Insufficient fastening of sheet metal copings, gravel stops, counter flashings
- Vegetation growth on roof due to ponding of water and dirt accumulation on roof
Modified Bitumen Roofs
- Blisters, especially at laps
- Loss of surfacing, especially SBS (a rubberized modifier) modified bitumen membranes
- Open laps
- End lap shrinkage (loss of overlap at roll ends)
- Membrane aging, surface crazing, pitting
- Membrane damage, punctures, or cuts
- Flashing defects, blisters, open laps, slippage
A typical modified bitumen roof – check the condition of the pipe support sleepers.
Single-Ply Membrane Roofs
- Membrane damage, punctures, cuts
- Inadequate attachment, ballast, or membrane displacement, shrinkage or wind damage
- Membrane aging, crazing, stiffening, or brittleness
- Flashing defects, open laps, loss of attachment
- Under-filled pitch pans or deterioration and cracking of pitch/sealant in pans
- Clogged/blocked or restricted drainage
- Debris, tools, scrap materials, and sharp objects left on roof by technicians
- Chemical exhaust, particularly oil and solvents (from kitchen vents)
- Collapsed, wet, or damaged roof insulation
- Insufficient fastening of sheet metal copings, gravel stops, counter flashings
- Poorly sealed flashing terminations and loose termination bars
- Check for tenting of base flashings due to membrane shrinkage
- White, high-albedo roofing systems must be washed regularly to maintain their ability to reflect heat from the sun. A dirty roof will not operate as designed
A dirty high-albedo roof will not reflect heat as designed.
Shingle Roofs
- Splits in shingles
- Shingle cupping/curling
- Loose/missing shingles due to blow off
- Improper attic ventilation (causing cooking of shingles)
- Exposed fasteners that are not caulked/sealed
- Loose ridge vents due to improper nailing (nails too short)
- Hail or other physical damage to shingles
- Loss of gravel surfacing on shingles
- Moss/fungus growth on shingles
- Clogged gutters causing rot of decking near perimeters of roof
- Kick-out flashing missing where lower elevation roofs intersect walls
- Excessive layers of previously installed shingles
- Improperly sized crickets at chimneys or mechanical penetrations
Hail damage to shingle roof.
Concrete or Clay Tile Roofs
- Tiles are installed with a 3″ headlap, or 2″ headlap over a sealed 30/90 hot mopped system with mechanical attachments through a strip of asphalt roof cement placed at the nail line. Less than 3″ headlap should occur over no more than 20% of the roof.
- Cracked or broken tiles must not be installed or allowed to remain on the roof. Repairs made with concrete or clay tile roof adhesives are acceptable.
- Tiles should be installed to permit thermal expansion. Tiles at valleys should be trimmed at an angle to prevent irregular pressure at corners.
- Headwalls, hips, and ridges of high-profile tile should be fitted with a weather blocking material such as coated polyurethane foam, mortar, mastic with felt paper, lead, aluminum, or UV-resistant neoprene, plastic, metal, or pressure-sensitive adhesive-backed tape.
Concrete roof tiles will fracture if sufficient room for thermal expansion is not provided during installation.
All Roof Types
- Trees need to be trimmed clear of building roof lines to prevent branches from contacting the roofs. Some trees may need to be removed.
- Beware of cell phone equipment installed on the roof. We have seen improperly supported equipment hung on rooftop penthouses or stair tower brick walls that were causing damage to the walls, improper flashing around steel pipe supports, and structural concerns about the weight of the equipment. Generally, cellphone companies take little or no care of the roof around their equipment. If a facility is considering allowing cell phone or cable company use of a roof, contractual provisions should be considered for roof protection and for repair of damage caused by equipment or its installers.
