Roofing nails secure both shingles and flashing. These nails are specifically made with a large head to secure the nail tightly as it holds down the shingle; the large head covers the nail hole completely to provide a nonleaking seal. Nails sometimes pop up when a severe storm lifts the shingle or an improper nail is used during roof installation. Popped nails eventually leak and must be repaired as soon as they are noticed.
Improper Nailing Technique
Nails that are not driven straight in may pop or slightly pull out due to normal roof movement. Remove any improperly driven nails -- a pry bar works best, but the claw on a claw hammer will suffice. Fill the holes with roofing cement or an exterior roofing adhesive, and drive another roofing nail in next to the original one. Cover the new nail head with roofing cement or adhesive.
Damaged shingles may occur from situations such as severe weather, fallen tree branches or even items like balls being thrown up onto the roof. In these cases, the shingles flex and have a tendency to pop up the nails that are holding them down. The popped-up nails must be removed and replaced with brand new nails. If the shingles are broken, cracked or torn, they must also be replaced. Drive the new nails in straight and fill in the old nail holes with roofing cement or exterior roofing adhesive.
In areas that are prone to storms, popped-up nails may occur because the singles have not been secured properly to the roof. Most shingling requires four nails per shingle. Storm nailing requires six nails per shingle. If storm nailing has not been done in areas where storms or high wind are common, popped-up nails occur when the shingles flex violently during a storm. If a roof has not been storm-nailed in places where storms or high winds are prevalent, all of the popped-up nails must be removed, the holes filled with roofing cement or exterior-grade roofing adhesive, and the entire roof area renailed with six nails per shingle to prevent popped-up nails in the future.
Flashing is a metal collar that goes around such things as chimneys, roof vents and skylights. When the collars flex during normal roof movement, a nail may inadvertently pop up. The chances are also great that if the nail has popped up, the flashing has also popped up or has become slightly bent upward. When a nail holding flashing pops up, the nail must be replaced with another nail alongside. Fill the original nail hole with roofing cement or an exterior-grade roofing adhesive. Then cover the area with roofing cement that is applied liberally. Check the joints where the flashing edge meets the roof. Repair any cracks or worn sealant using roofing cement applied with a putty knife.
Nails that are not made for roofing jobs (like those that have small heads), are not long enough to penetrate the roof sheathing or have smooth shanks will pop up. Improper roofing nails are most likely used for roofing repairs, patches or for additions like vents or skylights. If they pop up, replace them with a genuine roofing nail driven off to the side of the original hole and seal the hole where the improper nail came from.
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