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 ROOFING
Built-up roof-Continued
Bituminous
Splits
Tears
Punctures
Absence of protective coatings
Separation from vertical surfaces
n Bare spots - Bare spots expose the plies directly to the elements which
can accelerate deterioration. Check for:
Alligatoring
Deteriorated felt
n Blisters - Blisters are an indication of moisture or gas between roof plies.
Do not apply enough pressure to rupture blisters as this will allow water
intrusion. Blisters do not necessarily indicate roof system failure. Check
for:
Punctures
Splits
Water - by gently touching to see if water will come out of blister
n Pitch pockets
Shrinkage
Absence of bitumen
Deterioration of perimeter metal
n Ponding water - Ponding around roof penetrations will result in leaks.
Ponding of a large area could indicate a possible structural defect.
Stopped up roof drain will cause ponding. Check for:
Location
Percentage of roof surface which displays ponding
n Penetrations - The majority of roof failures begin in areas near
penetrations. Check for:
Proper flashings
Ponding of water near penetration
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