What about splitting?
I was told by a shop teacher years ago that screws will make wood split more readily than nails. I have driven tens of thousands of screws (always drilling pilot holes first), but I can’t remember the last time I drove a nail with a hammer. So I don’t really have enough data for a comparison.
I would guess that the shop teacher was right, but only when considering driving screws without pilot holes.
Not to pile on, but I worked on a crew that put up two to three houses a week, with the sole purpose of detonating a 500 pound ANFO car bomb next to them. I participated in over 100 houses, and the carpenter shop supervisor must have worked on at least 2,500. The motto of the crew was often, “They’re going to blow it up, anyway,” so many things were done haphazardly. We still used screws to hang the drywall. We did get one of those neat “machine guns”, as we called them, right before I left the crew.
And the self feeding cordless screw gun made that obsolute. Imagine holding a piece of drywall up to a ceiling and as fast as you can squeeze the trigger you’re driving a screw into it. Attaching a screw every 2 seconds makes the job go considerably faster.
Maybe for the fancy belt-fed ones, but you can get a 25lb bucket of drywall screws for $60.00 and 25lbs of drywall nails for $50.00. And 25 lb of screws will put up a heap o’ drywall. So I’d be surprised if you even used $300.00 (125 lb) worth in your average house, much less the 750 lbs of screws you’d need to see a $300 difference.
When I hang drywall, the supporting members are glued before the rock is pressed into place. Then I use a few screws per sheet, just enough to meet code, because the adhesive is going to do the job after it sets. No fastener pops, and no callbacks.
Yeah, that’s what you get when a source doesn’t explain the math or assumptions going into their figures. Of course, I could have misremembered…don’t think so, but could be.
However, your figures make me even more :mad: at the lengths contractors will go to save a nickel here. From prior posts, this doesn’t seem to be the case everywhere, fortunately.
This would be true with a machine screw (where the threads are cut into the shaft making a constant “V” shape intended to mate up with female threads) but on a wood screw or drywall screw the threads are formed on the shaft by rolling and are spaced far enough apart that there is essentially a solid shaft between them and no significant stress concentration area. The other thing to bear in mind is that while machine screws are (or at least should be) held in place via a preload which places the threaded area in tension that is opposed by the facing surfaces of the bolt head and nut, a wood screw typically has little or no preload, and instead remains in place purely by local, untensioned friction between the threads and the wood. So a wood screw should have essentially the same strength as a nail of the same minor diameter, and in fact it is rare to see a wood screw fail in pure shear except under high impact situations; more often, either the head pops off or the wood media itself fails first.
Your point, however, is entirely valid for machine screws, which should never be placed in shear across the threaded area for precisely the reasons you mention.
Stranger
What happens in twenty years when the glue dries out, the wood studs warp a bit, and the drywall starts separating from the studs? Fewer screws means a little bit less patching and sanding (I never can seem to get rid of the screw holes entirely, especially if the wall is given a gloss finish) but I’d rather that than have drywall panels suddenly popping free of the wall.
Then again, I foxing hate gypsum board. The stuff is an anathema to my calm disposition.
Stranger
If you’ve ever done demo on a properly glued wall, you’ll note that the glued areas remain firmly attached to the studs, with part of the drywall stuck on the opposing face. Within a week or so of application, the adhesive has cured-there’s no long term drying out. Assuming the framing lumber wasn’t fresh from a swamp, it will be close to even with the ambient RH. Drywall is also somewhat flexible, such that it will move along with the framing. NOT using adhesive is what leads to future problems with drywall and fastener failure.
Dopers have the coolest jobs…
Former construction manager here. Nails are much stronger in shear than screws. Wood screws are typically hardened, which makes them much more brittle than a framing nail of equal diameter. Screws are great for decking and drywall, but not for structural use. Also, a good drywall crew is amazingly fast with hammer and nails and labor costs trump material cost just about every time. Not to mention a drywall hammer cost about $15 and a fancy automatic screwgun runs more like $150. And hammers rarely wear out.
Pretty much - a lot depends on the type of nails, the timber, etc. One trick to prevent splitting I was shown was to deliberately blunt a nail by clipping the end off with wire cutters or a cold chisel - the nail then tends to cut through the wood fibres rather than parting them - or that’s the theory.
Oh, one situation where nails are more appropriate than screws: Dovetail nailing - where nails are deliberately driven in at an angle so as to prevent the whole joint pulling apart - not really possible with most normal countersunk screws, as they need to be driven perpendicular to the surface.
Dovetail nailing is particularly useful when fixing into endgrain (which, coincidentally, screws are pretty poor at)
I’m glad there is no drywall or wood in my home here. After living in the Mid East and Europe, my first time back in an American home was shocking - it felt very, very cheap and the hollow sound of walls was a bit unnerving. I know in the Western US, the wood/drywall serves a purpose related to earthquake survival, but it still feels cheap.
At least now I know screws are used nowdays. 
Heck, that was just the entry-level position. 
On average, nails are more cost-effective for most wood framing than are screws, and that’s the overwhelming reason they are used, particularly in a typical stick-built wood-framed house. Not only are they cheaper and easier to place (with either a hammer or a nail gun); they are cheaper and easier to remove if a minor on-the-spot adjustment needs to be made. A few seconds per fastener adds up when thousands of fasteners need to be applied.
Nails have some specific advantages. They are usually made of drawn wire which is stronger in shear* strength than a screw of the same outside dimension. Screws, as mentioned above, are typically more brittle. If you were to compare a 3 1/2" drywall screw to a 16d nail you would see a substantial difference in shear strength. The screw has a shaft narrower than the nail, and the material is much more brittle. Of course you can get screws that are much stronger than drywall screws, but as the material changes, the cost rises rapidly. (Note that such a “drywall screw” is a description of the type of screw and not a description of its use; screws used for drywall are much shorter.) A nailed joint can also be tweaked into position with a hammer. Nails are usually constructed of bendable metals (much more generous electrons, I assume; ask Stranger) and the resulting malleability is quite useful. A screwed joint is well… screwed if it’s even marginally out of position. The screw will snap or the wood will split if you start tapping around a screwed joint because screws are not usually made of very deformable metals.
Any framed home could be built entirely with screws, and if the right screws were chosen it would be stronger assuming they were placed with expertise. And there’s another rub. Most homes are built by crews who work under a crew boss who works for a sub-contractor who bids out to the general contractor–and there is no requirement that any of them have any formal training. Licenses, yes. But most framers do their job a certain way because that’s how they were taught. Screws over here; nails over there. Neither the workers themselves nor even contractors are a good source of information on why and how a particular solution is better.
Because stick-built houses assume certain materials will be used, construction standards tend to reflect the available cost-effective materials rather than reinventing the basic framing techniques. As an example, a nailing plate or hurricane tie (or adhesive) might be used where an alternate method such as screws or bolts could in theory provide an equivalent binding strength.
A joist is best and most easily secured into a box beam with nails, even if lag screws would work. A big old nail has a lot of shear strength; doesn’t split the wood without pre-drilling, and sits flush for the sheathing. And it’s cheaper by a wide margin. Binding strength is not an issue because the decking nailed on top of the box beam and the joists will bind the joist/box joint. Drywall is best and relatively easily glued and screwed. Subflooring? Almost always nailed (along with adhesive) but definitely better screwed if you don’t trust the adhesive over time and you don’t want squeaky floors.
On average, I’d say, nails are over-used and used poorly. On the other hand, most construction codes over-build for typical loads. We don’t see too many houses falling over. They just sorta loosen up and crack here and there. The quality of the craftsmanship and materials is usually more of a factor than the choice of fastener.
*Probably not technically shear, but perpendicular stress…