Roofing with a nail gun or hand nailing, which is a better way to install a roof? The simple answer is. . . . It all depends on the person holding the hammer or air gun.
Most DIY’ers will buy shingles and not know how to fasten them to the roof. Most professionals use pneumatic nail guns and air compressors. There must be a reason why. It is speed? A nail gun is a tool that has a tray that stores the fasteners (nails). One by one these fasteners are driven through the asphalt shingle and into the roof deck by air pressure. The fasteners should have enough power to drive a nail into the roof deck 3/4 of an inch or through it to meet manufactures specifications and local codes.
Speed without experience is not good thing. Using a fast nail gun can be dangerous and does not insure a good roof installation. It is seen all the time. Nails not placed correctly WILL cause roof failures and this is very common with nail guns.
Hand nailing can be fast but the same man, at the same skill level, doing the same job will perform faster using a gun and compressor. There just are not many roofers have the skill level to keep up with a man with a gun.
"Under pressured" will leave the nails high causing the shingle above to be lifted and suspect to wind blow offs. Some shingles after roof traffic will cut through the upper shingle leaving an exposed nail head. Hand nailer can tell better if a nail is high and will give it another hit.
"Over pressured" tools drive nails too deep cutting the mat and loose holding down power needed to withstand high winds, or in some cases becoming dislodged and slide down the roof. The hammer head is larger than the driver in a nail gun so overdrive nail is rare for the hand nailer because the hammer stops at the surface of the roof.
These are just a few problems nailing to fast with a gun. By slowing down and placing the nails in the proper nail zone and having the proper air pressure, nail guns can be very helpful with getting the job done faster and without the fatigue of hand nailing.
Now I know there are a few old school roofers that sell ” hand nailing is the best” and that’s fine. Using a nail stripper and a roofing hammer is a great way to install a roof.
However, having well trained and skilled craftsmen using nail guns that can produce very good roofs . . . . that meet and exceed requirements of building officials and manufactures specifications. Again, it is not the tool but the one using it, that makes a good roof.
So what’s the answer? Both are approved ways to install shingles. It is all about timing, skill level and money. Overall, there is less chance of error with hand nailing.