Nail guns... when and why?

Nail guns have made certain parts of building a house faster, no doubt about it. But there's certain times I prefer to pre-drill and hand-nail, and I'll explain why.

These days, on most houses everything tends to be gun-nailed: it has to be, for price constraint.

There are two big problems with gun nails. Firstly, the placement of the nail. It's just the nature of using a nail gun that you don't get each nail in an optimal position every time, and sometimes your timber can move in the process. The second issue is splitting the timbers you wish to join. Gun nails are driven forcibly into the timber which, depending on the type of timber and the position of the nail, can cause it to split. In laminated beams, this can act like a wedge and cause the sheets to split.

'Nominal Nailing' is a term which  specifies the number and type of nails required at any part of a building. By definition, if some of the nails you're using can't do their job in an effective way (because the timbers have been split in the process) then your 'Nominal Nailing' isn't as specified. Look at many building sites and you'll see that someone has split a timber and then nailed around it to try and hold it, which often just adds to the problem by weakening the join further. Engineers do mandate secondary tie-down methods in their specifications. These fasteners add strength to joins and are not designed to be the sole point of connection.

I still insist on pre-drilling and hand-nailing critical structural elements: bearers to joists: rafters to top-plates and beams. Like this:

Rafter to veranda beam join on 25 Chapman Place.

This kind of clean join just isn't achieveable using a nail gun. You can see that the nails are positioned neatly, the beam hasn't moved, and that the laminated timbers haven't split. The holes were pre-drilled and the galvanised nails (using galvanised nails helps prevent corrosion when used with this type of treated timber) were hammered in by hand.

Yes... it takes longer. It's old-school, but it's a better method and gives me a great sense of satisfaction!