Three-inch self-tapping roofing screws are most frequently used to secure metal roofing, with the exception of the one-inch roofing screws which can sometimes be sufficient to attach the first edges of metal roofing sections. If, however, a metal roof is being installed on top of an existing asphalt roof, the first edges of each of its sections will have to be secured with three-inch roofing screws.
Self-tapping roofing screws are essential for simplifying metal roofing installation which has neither been factory pre-drilled nor dimple, because they are both faster to secure and reduce the risk of injury from snapped screws.
Sealing Metal Roofing
Because metal roofing has nothing in it which will seal the holes around roofing screws in the way asphalt roofing materials seal the holes around roofing nails, roofing screws manufacturers make two types of roofing screws. The first will have a sealer cap of metal which is seated directly on the roofing material and secured by the screw itself. The second will have washers of plastic or rubber integrated into their bodies, which automatically seal the holes in the roofing as they are inserted.
Roofing Screw Gun Alternatives
Metal roofing should not be hand-installed, because it demands that roofing screws be separated by no more than two feet. Driving this number of roofing screws by hand would quickly exhaust the hand and arm strength of the roofing crew, and relying on the rechargeable roofing screw guns now available would mean to switch to fresh batteries at hourly intervals. Because most rechargeable roofing screw gun batteries require a charging time of one hour, each roofing crew member would need four batteries to complete an eight hour shift!
One solution would be to use an electrically powered roofing screw gun which can operate without interruption for an entire day. Most of these screw guns are manufactured with adjustable power levels, enabling their users to select just the right amount of force to use when installing the roofing screws.
Roofing screws which are driven too deeply into a roof can either damage the roof itself or have their heaps snapped off, making them very difficult to remove. The disadvantage of using an electrically powered roofing screw gun is that it rewires the use of a long extension cord, which can be a hazard for those working on the rooftop.
The third alternative for installing roofing screws is the pneumatic screw gun, which is powered by an air compressor. The pneumatic patio roofing screw gun is attached to its air compressor by a long air hose, which like the extension cord on an electrical screw gun can be a real encumbrance when it is dragged around on the roof.
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