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11.7 Rooftop Inspection
11.7.1 Only after all preliminary evaluations and inspections have been done, can an actual rooftop inspection be made with maximum
effectiveness. To ensure that all information gained during this rooftop inspection can be properly utilized during the decision making process,
the information gathered should be recorded at the time of the inspection. Photographs of the general layout and specific deficiencies of the
existing system may help the inspector refresh his memory at a later date, or illustrate conditions to decision makers who were not present
during the inspection. Annotated roof plans and roof inspection checklists will provide similar assistance. Only after all the information
gathered is considered as a whole can a comprehensive course of action be determined.
11.7.2 If a roof plan is not available before the rooftop inspection is made, one should be made during the inspection. Existing roof plans
should be checked for accuracy, and any additions or demolitions should be so noted. Location of drains, scuppers, expansion joints, rooftop
equipment, deck types, flashing details and slope of roof are just some of the items that should be noted on the roof plan.
11.8 General Overview
11.8.1 The first step of a rooftop inspection is a general overview of the roofing system. The first quick glance around the roof can set the tone
and give direction to the rest of the inspection:
11.8.2 What is the general condition of the roof? Debris, standing water, vegetation, and obvious signs of abuse, in many cases, indicate
long-standing and far-reaching problems which may eliminate roof recover as a viable alternative. Initial impressions, however, must be
followed up with specific inquiries.
11.9 Perimeters
11.9.1 The perimeter of the building should be the first point of inspection, since the majority of roof leaks and related problems occur in this
area. Base flashings should be checked for integrity and watertightness. Counterflashings should be checked to ensure that they are in place,
properly attached, caulked where necessary, and performing their intended function. Metal, stone, concrete and tile coping should be checked
for solid attachment and watertight-ness. A missing piece of coping can allow a significant amount of moisture into the roofing system in a
relatively short period of time. Coping joints should be checked for their integrity. Loose or missing grout, or deteriorated or improperly applied
caulk, can be a source of water entry to an otherwise stable base flashing system. The inside of parapet walls should be checked for cracks,
water stains, moss, and algae that would indicate water entry from a source other than from the base flashing.
11.9.2 The base flashing itself should be checked to see if it has physically deteriorated. Improper nailing along the top of the base flashing
frequently causes the base flashing to either sag below the level of the counterflashing or to fall off the wall entirely. Blisters behind the base
flashing can indicate water entry. Diagonal wrinkling, or "tenting" of the base flashing material, is a classic sign of differential movement
between the wall and the deck. "Bridging" flashing materials can indicate differential movement or membrane shrinkage. Splits in BUR or
modified bitumen flashing materials are normally a clear indication of differential movement within the structure. Laps in the base flashing
material should be checked to see if they are solidly adhered. Lightning arrestor systems, sign and antenna support systems, and conduits are
frequently attached to a parapet wall after the completion of a roofing system. Those attachments may be a source of water entry if improperly
flashed or maintained.
11.9.3 Gutters should be checked for rusting of metal and clogged downspouts. The stripping at joints in the gravel stop should be carefully
scrutinized, since leaks caused by splits at this location are common. A gravel stop whose profile contributes to ponded water can create
problems for the rest of the roofing system, as well as being a source of leaks in itself.
11.10 Field of Roof
11.10.1 After a thorough inspection of the roof perimeter has been completed, attention should focus on the main body of the roof. Areas of
ponded water can be a result of inadequate slope in the original design, deflection of the structural deck, improper installation of the original
roof insulation, or deterioration of the insulation. The actual cause should be determined and noted on the roof plan. Ponded water is one of
the most harmful conditions for any type of roofing system, whether existing or new. If ponded water is not present at the time of inspection, the
inspector should look for signs that would indicate its presence during periods of precipitation. Stains on the surfacing and vegetation growth
are common indicators. Vegetation growth is harmful, not only because it indicates a condition of ponded water, but also because the roots of
the vegetation can penetrate the membrane and allow for infiltration of moisture into the system.
11.10.2 Obvious signs of abuse, such as discarded lumber, masonry blocks, steel, and other construction items, should be noted, and the
membrane checked for possible damage. Vandalism, such as bullet holes, arrows, and welding rods which have been intentionally embedded
in the roof, should also be noted.
11.10.3 The surfacing of the membrane should be inspected to determine its condition. Wind scouring of gravel surfaces is a common
problem, particularly at corners which face the prevailing winds. Excessive gravel may be a problem in that it not only places too much weight
upon the structure, but also allows an accumulation of dirt and debris, which may foster ponded water and vegetation growth. Excessive
surfacing of any type may promote membrane slippage in steep slope applications. Too little gravel can promote premature aging of the
membrane, due to lack of protection from ultraviolet attack. Roof coatings, such as Hypalon on single ply membranes, and aluminum roof
coatings on built-up membranes, should be checked to see that they are present in quantities sufficient to perform their intended function. In
extreme cases, "alligatoring" of asphalt coatings can literally tear open the membrane. Industrial residue, oils, animal fats, or other chemical
contaminants should be identified and eliminated at the source.
