I have now borne witness to and participated in three buildings being constructed.
1. One with nails only.
2. One with mostly nails and some screws.
3. One with all screws.
Partial List Of Pros & Cons Of Nails
Cheaper.Thicker, thus stronger under certain conditions.
Faster to install for the average person.
Don't require a power tool (impact driver or drill)
Bend easily if not struck flush. Thus potentially creates waste.
Harder to remove, thus usually damages the nail and the wood.
Make corrections harder.
Will pull out of wood when that wood is directly exposed to weather. This can weaken the structure and requires additional time to hammer back in. There are special nails to address some of this, such as spiral nails for decks and ringshank nails for subfloors. This might require a little more planning, researching or finding the right person in the hardware store.
Have less holding power under certain kinds of forces and stresses
Partial List Of Pros & Cons Of Screws
Are thinner due to the threads on the screws which are created by cutting out a portion of the metal.Expensive
Are slower to install until you get used to it, which is the same learning curve when using nails.
Require power tools, cords and/or batteries.
Do not bend easily when installing.
Are susceptible to being “stripped” by the power tool, thus making the screw unusable.
Easy to remove and make corrections, thus does not damage wood.
Do not pull out of wood when that wood is directly exposed to weather.
Have less holding power under certain kinds of stresses.
Misconception
Based on videos on Youtube that compare screws versus nails, those stress tests seem faulty for the following main reason.Those tests usually consist of a screw and nail partially inserted in a piece of wood and then one at a time, the nail and screw are struck from the side with a hammer. This is not a real world test of stress on nails and screws.
Here are some reasons why not.
A screw or nail under stress will be fully seated all the way into the wood.
The screw or nail will not be encountering the stress as a single item, but also in conjunction with multiple other screws or nails.
All components that are joined and constructed are working together. Thus they all encounter the stress and that stress is spread out among the wood and the fasteners. Bottom line: The most important basic difference from my point of view is that screws hold two items together more securely to prevent them from pulling apart or separating from each other. On the other hand, nails provide greater strength against lateral side-to-side force. So the optimal solution is to use a combination of screws and nails when constructing a building So then the decision to use screws or nails in a certain situation, comes down to the situation and your preference, thus also understanding some of the pros and cons and the few slight adjustments that must be made to the process. A nail is a smooth screw.
A screw is drill nail or a nail that bores.
Thus a screw and a nail are forms of each other.
Thus, like all such things that are forms of each other, there are times when they are used alone and times when used together.
Take the simple example of water in liquid and solid form. Sometimes we drink water without ice, sometimes with ice and sometimes we eat ice by itself. So, just like our ancestors taught us through African Deep Thought, everything in the universe is all good when understood when not to and when we should.
On Further Thought, 11.23.19 Update
Let me go back to the stress test mentioned above that anyone can view by searching videos for “the difference between nails and screws.” Most of these tests tell us nails are stronger than screws because screws will break or snap into two pieces much more quickly than nails. Truth is, any force capable of bending or snapping off screws, will cause significant structural damage and likely partial or complete failure of that structure and also have the same effect on the same structure if built with nails. Even though nails might not break as quickly, the structure will still be weakened because the structure will be out of balance due to nails bending. This imbalance will likely result in partial or complete failure of the structure. A building's strength also depends on its balance and equal distribution of weight and other forces. This balance being largely determined by square, level and plumb.Two buildings side by side, one built of screws and one of nails, will both fail under the same forces if nails and screws are the only difference between the two buildings. Some of those forces being water or snow on the roof, earthquake, hurricane, tornado. The only difference might be the failure of one building might happen slightly sooner in some instances such as the downward force of weight on a roof or the upward force on a roof due to wind. In the first instance, the nailed roof might last a little longer and in the second instance the screwed roof might last a little longer. In both instances, if one roof is damaged or fails, it is highly likely the other roof will at least be damaged. This is why extra building measures are used to combat and offset certain forces in areas where those forces are above average. For instance, in heavy snow areas, extra strengthening measures must be used. In high wind areas, extra strengthening measures must be used.
Screws and nails are simply one component of a building, many other components and choices made in how the building is constructed also affect the building's structural integrity. This includes, but is not limited to number, size and type of screws and nails used (more is not always better), type of construction material, quality of construction material, dimensions of the material, spacing of the material, quality of how properly those materials are joined and so on (this includes using the proper practices and making adjustments for the geographic area). So once again when considering whether to use screws or nails, if you focus mainly on how strong a screw or nail is, your analysis will be very incomplete as to the difference that makes when constructing a building. Why? Because there are many other factors involved that must also be taken into consideration. Therefore the premise and the question “screws versus nails” is faulty.
