When it comes to the factors that can determine the life expectancy of a roof, the major components such the shingles, deck and underlayment tend to get the most attention. However, one of the most important aspects on a roof may be one of the smallest; the nails used to fasten the shingles. Here are 4 ways that their improper use can affect the performance and the service life of a roof.
Exposing
the nail heads - Nails that are put in at a location on shingles that is too
low to be covered by the next row higher will be exposed to direct sunlight and
moisture, which will speed the process of corrosion. These exposed nail heads
are referred to as "shiners" because of their tendency to reflect
sunlight. Constant exposure to the elements will eventually weaken the nail
head to the point where it breaks off, leaving shingles unattached and creating
the potential for tiny leaks across the roofing system. If you notice exposed
nail heads after the installation of a new roof or a repair, call the installer
to have the shingles replaced and re-fastened properly.
Nailing
near the top of the shingles - This may be the result of over-compensating to
avoid shiners, but any time nails are hammered in too high, they may not reach
the underlying shingle or, if they do, the penetration will be too shallow to
make a firm connection. These weak or non-existent connections between shingles
make the entire roofing system prone to being blown off by high winds.
Over-driven
nails - Nails that are driven too far in to the shingles can go through the
protective outer layer and expose the inside of the shingle, which can lead to
a faster deterioration process. In addition to penetrating the outer layer, the
tiny recesses can trap moisture, which can corrode nail heads and saturate the
unprotected areas of each shingle. To make matters worse, over driven nails can
void the manufacturer's warranty on materials.
Using
the wrong length - Nails that are too short will not fasten the shingles tight
enough to provide full protection. On the other hand, nails that are too long
can fully penetrate the roof deck, eventually leading to numerous small leaks
across the roofing system.
The best way to avoid these issues is to hire a roofing company that has
their installers receive training directly from roofing material manufacturers.
Installers that demonstrate expertise after comprehensive training can be
designated as “Certified Master Roofers”. With an installation performed by
Certified Master Roofers, the issues listed above are extremely unlikely to
occur.