Pneumatic hails are struck by a driver blade that is the same size as the nail head. If the wood under the roofing is harder because a rafter or lathe is under the deck, the nail might not set flush and the roofer won't know it until the homeowner looks up and sees the fish mouth in the roof. The hand nailing roofer feels what happens through his connectedness with his tool. He feels and hears if the hatched hit solid wood.
More likely the nail of a gun will be over driven whereas the hand driven nail can only be set flush because the hatchet is larger than the nail. Over driven nails hold onto nothing.
The operator of a nail gun often crosses the gun across him so the nail goes in at an angle. If the hand nailer does this you'll hear Spanish profanity.
The air nailing dude has to protect and maintenance his heavy and expensive compressor, guns, and hoses. Every morning he must load up his truck or risk theft, unload at the job site, string out the equipment, find electricity, and repair the tools as he goes along during the day. The hand nailer gets his hatchet out of the truck. There is no air hose dragging across the new but not sun sealed roofing.
The air guy has to load up his stuff if it didn't get stolen during lunch and then unload it at the house. The hand man throws his hatchet in the truck bed.
What if a breaker is thrown while the air man is using your electricity? Do you have to come home from work? Will the roofer quit and go home because he's not proficient with a hatchet or doesn't have one?
The gun roofers might start the day fine but as the sun heats up the roofing it changes consistency. Freshly opened bundles are stiffer than the buttery ones that have been open for a while. Cold shingles shatter under the thump of a gun. Think of a karate punch. The strength comes from speed times weight giving the punch its force but the black belt also makes his fist smaller by using two strong knuckles instead of spreading out his power on four. The nail gun compresses the force in an area no bigger than the nail allowing for countersinking. .
With traveling to the job, tearing off, cleaning up, paper installing, loading the heavy roofing, flashing, painting, trimming edges, going to the dump, and more cleaning up, what percentage of the job is actually nailing? Isn't it the one most important factor in a roof? How the roofing is attached is without a doubt the numero uno item on a good roof job. All other things pale in comparison. Do you have a roof or did it slide off?
Now imagine a group of men about to roof your house. If they pull out their hatchets and get after it like banshees on steroids then you know. you got your roofers. The rookies need the air tools to make up for their rookieness.
Lastly, hand nailing is green. Less electricity, manufacturing, transportation, and a better job. The government ought to give a tax credit for it.
Those are most of the reasons Jon Wright Roofing hand nails it's composition roofs. That's all an expert would use. Some of the better roofing companies in Dallas and Fort Worth get it but at a recent seminar there were a lot of snickers coming from the newbys when I gave an enlightening discourse on hand nailing. A few of these guys made comments much later about how I was still selling hand nailing.
As long as these guys are out there, there will be a lot of roof repairs to be performed in Dallas and Fort Worth.
A kid would eat ivy too, wouldn't you? They eat old shingles.