Qualified staff should perform routine roof inspections monthly. Remove all debris, leaves, paper, vegetation, and other items that can clog drains and gutters, and clean out roof drains.

The Pennsylvania Green Buildings Operations and Maintenance Manual says, additional inspections should be performed after severe weather (e.g., high winds, heavy snow or ice loads, hail), installation or servicing of rooftop equipment, or building construction. Avoid chopping ice be damaged. After removing vegetation with large roots, patch the holes left in the roof membrane.

Qualified staff should thoroughly inspect the roof twice a year — once in the spring and once in the fall — to identify problems such as split seams, separated layers, failed flashings, clogged drains, and surface punctures. The inspections should include an examination of the building interior areas directly below the roof.

Pay particular attention to rooftop equipment and other roof penetrations, such as skylights, exhaust fans, air handlers, and vent stacks. Grease from exhaust fans, oil leaking from HVAC units, and air pollutants can damage roof materials.

Specialized or extensive roof repairs that are identified during routine inspections may need to be performed by a roofing professional if building staff have not been trained in the proper procedures. The more people who walk on the roof the more potential for damage. Limit roof access to authorized personnel. Keep foot traffic to a minimum.

Consider adding a light-colored reflective coating to the roof to reduce the building energy use (by reducing the solar heat gain in the building) and extend the life of the roof (by reflecting the ultraviolet rays in sunlight that break down many roofing materials).

Reflective, or “cool roofs,” can provide a building with up to 50 percent energy savings and reduce peak cooling demand by 10-15 percent.

Dark-colored roofs can absorb more than 70 percent of the solar energy that  falls on them, making the rooftop temperature as much as 100 degrees F above the ambient air temperature. The heat is absorbed by the roof, radiated upward into the atmosphere, and radiated downward into the building. Also consider specifying white or light color finishes on rooftop equipment. Paint existing equipment with a light-colored paint the next time the equipment requires painting.

When wind damage occurs, primary consideration should be given to removing the damaged, wet or deteriorated materials and making temporary or permanent repairs as quickly as possible.

The permanence of repairs will depend on the nature and extent of damage. Wind can damage roofs in a number of ways. According to the FM Global Property Loss Prevention Data Sheet, “Repair of Wind Damaged Roof Systems,” types of damage include:

• Perimeter flashing components removed or loosened;

• Roof covering and/or insulation removed;

• Roof covering and/or insulation delaminated;

• Roof deck panels dislodged or lifted;

• Roof covering damaged by impact from wind-blown objects;

• Dislodged roof protrusions such as vents and skylights.

In a majority of losses, roof covering wind damage begins at the perimeter flashing. The roof cover edge is rolled back by the wind after the perimeter flashing assembly has failed. Because of this, it is extremely important that all flashing damage be repaired adequately and promptly.

Wind damage to roof insulation and coverings usually begins at or near the windward edge, particularly at the corners, and progresses inward. The damage can take the form of direct uplift or peeling action of the wind working on the unprotected covering after initial damage occurs.

In reroofing design, several factors should be considered in determining whether or not the existing roof system should be left in place. These factors include, but are not limited to:

• Condition of the existing deck and insulation;

• Load capacity of the deck;

• The need for additional insulation; and

• The extent of damage.

Prior to initiating permanent repair procedures, the extent of wet materials should be determined. Wet materials should be removed.

There is some controversy within the roofing industry as to what amount of moisture is excessive within a roof system. One measure is any amount above the equilibrium moisture content. A second measure is that amount of moisture that reduces the thermal resistance of the insulation by 20 percent. Other measures are also used. For the purpose of this data sheet, wet insulation is defined as that which is weakened to the point where wind uplift resistance is deficient or that which will cause or significantly increase the potential for corrosion of the deck or fasteners.

There is no controversy, however, that materials that are obviously wet should be removed. A roofing consultant should be engaged to evaluate the existing conditions.

Flashing Damage

If the perimeter flashing is bent outward from the face of the wall because a hook strip was not installed at the lower edge, but the metal is not severely damaged, it can be pushed back into place and secured with screws and rubber washers. Nails should not be used. If more severe damage is evident, the flashing system should be replaced with an approved system.

Roof Deck Damage

If the existing roof deck shows signs of rotting or similar deterioration due to a damaged roof covering, the defective areas should be removed down to the structural supports, and replaced with properly secured approved materials. If the roof deck is damaged due to the interior environment, the deck should be replaced with a deck material tolerant of the occupancy.

If the above-deck components have been removed, the securement of the deck should be checked for adequacy. If additional deck securement is needed, it should be applied in all areas where necessary to reduce the potential for future damage.

Roof Cover Removed

In some cases, only the roof cover is removed (delaminated) from the insulation. If the existing insulation is dry, in good condition, secure, and has not otherwise been damaged, it can remain in place. A new roof cover can be mechanically fastened through it. As an option, additional insulation can be mechanically secured through the existing insulation and a new roof cover then applied.

If the delaminated roof cover is a single-ply membrane and it has not been severely damaged, it can be refastened through the insulation using mechanical fasteners.

Roof Cover and Insulation Facer Delaminated

If the roof cover and the insulation facer have delaminated, the above-deck components should be replaced or the recover components (new roof cover and/or insulation) should be mechanically fastened through the existing materials to the deck as outlined above. For single-ply covers, refastening may also be acceptable, depending on the membrane condition.

Roof Cover and Insulation Uplifted

If the existing roof cover and insulation have been lifted from the deck, sufficient damage may have been done to warrant removal and replacement of the materials.

When a mechanically fastened base sheet or insulation is removed from a roof deck by wind, it may be due to one of the following deficiencies:

a) Fasteners were improper for deck;

b) Fasteners spaced too far apart;

c) Fastener head/plate too small;

d) Insufficient fasteners at roof perimeter and corners;

e) Fasteners corroded.

Deficiency ‘‘a’’ would be characterized by fasteners pulled out of the deck. Deficiency ‘‘c’’ would be characterized by the insulation or base sheet tearing over the fastener heads. Deficiencies ‘‘b’’ and ‘‘d’’ could be characterized by either or both types of damage. Corrosion, deficiency ‘‘e’,” usually results in ‘‘thinning’’ of the fastener shank and/or broken fasteners.

Except for ‘‘e’’-type damage, the repair should include replacement of the fasteners in the damaged area with the appropriate type and adequate number followed by installation of a new roof cover.

Repair of the existing cover may be possible with certain single-ply membranes.

Corroded fasteners are usually an indication of excessive moisture. If corroded fasteners are found, a moisture survey should be conducted by a roof consultant to determine the extent of wet materials. These should be replaced with proper materials.

Wind damage can also be due to a base sheet or insulation of insufficient strength or thickness. Uplift forces are concentrated at fasteners and a weak base sheet or insulation can fracture around the heads of the fasteners (see ‘‘c’’ above).

This type of deficiency can be corrected by increasing the fastener density, using a stronger base sheet or insulation, or using a larger fastener head or plate. If the original roof system has been improperly secured, the entire system should be refastened, even if only a portion is damaged. This will minimize the possibility of further damage. If the existing construction is dry, the new fasteners can be driven through the existing built-up roof (BUR) into the deck, followed by application of a new roof cover.

If necessary, fastener strength should be checked by actual pull-out tests on fasteners driven into the deck. Pull-out tests should be run on fasteners used with cementitious wood fiber, gypsum or lightweight insulating concrete decks.

Wind damage can occur to roof systems that have been exposed to moisture. Causes of moisture can include leaking roof covering, exposure to moisture prior to application of roof cover, or a high humidity atmosphere below the deck.

Prolonged exposure to moisture can result in deterioration of the deck, insulation and fasteners. These deficiencies may not be apparent until the roof is damaged by wind. If such exposure is suspected, a moisture survey can be conducted by a roofing consultant to determine the potential for problems. These deficiencies should be corrected by replacing the wet or deteriorated materials. ❑