Field note
Basics of Sheetrock Screws and Drywall Screws
Sheetrock screws, also known as drywall screws, are the industry standard for fastening drywall sheets to ceiling joists or wall studs. Between the threads, lengths, numbers, gauges, heads, and points, deciphering what type of drywall screws to use may seem impossible.
In reality, the wide array of sheetrock screws available for purchase can be narrowed down to a few options that cover most drywall screw uses. A basic understanding of the main features and specific purposes of drywall screws will provide enough know-how to get started on any drywall-fastening project. These main features are the drywall screw length, drywall screw threads, and drywall screw gauges.
Sheetrock Screw Length
The first factor to consider when purchasing sheetrock screws is the screw length. The correct drywall screw length depends on the type of material being used. For general construction, screws can be up to 8 inches long for use in thicker materials. Since drywall is so thin, 8-inch screws won’t be used, but the thickness of the drywall still determines drywall screw length. The rule of thumb for screw length is:
For ¼ inch drywall, use 1-inch to 1 ¼-inch sheetrock screws.
For ½-inch drywall, use 1 ¼-inch to 1 ⅝-inch sheetrock screws.
For ⅝-inch drywall, use 1 ⅝-inch to 2-inch sheetrock screws.
Different thicknesses of drywall panels serve different purposes, so purchase a longer drywall screw in lengths appropriate for your project.
The most common drywall thickness for residential housing is ½-inch, which can be used for most purposes. ⅝-inch drywall is used for increased soundproofing and for meeting certain fire codes in commercial buildings, as ⅝-inch thick type-x drywall stunts fire spread. Thicker drywall requires different sheetrock screws, so be sure you know the drywall thickness prior to buying your screws.
¼-inch drywall is thin and flexible and therefore often used to cover curved areas like dish-shaped ceilings. Another option is to use drywall nails, but of course, you would need to be sure these are allowable for your application.
Sheetrock Screw Threads
Drywall screw threads can be broken down into two types, each of which serves different purposes: coarse and fine.
Coarse Thread Sheetrock Screws
Coarse thread drywall screws, or w-type screws, are best used when fastening drywall to wood studs. The wider, deeper threads get a better grip on the wood grain, allowing for a more secure pull on the drywall against the wood stud.
However, be forewarned. Since the coarse-thread screws have wider threads, the larger burrs are sharp and can embed themselves into fingers. It’s best practice to wear gloves when working with coarse thread wood screws and drywall screws.
Fine Thread Sheetrock Screws
Fine thread drywall screws are used primarily when working with metal studs. These screws are self-threading, meaning the sharp threads surrounding the screw are able to efficiently cut their own secure path into the material (in this case, metal).
Fine thread sheetrock drywall screws, or s-type screws, are used for metal studs as opposed to coarse-threaded ones because the coarser threads less effectively drill into metal, oftentimes chewing it up, resulting in a weaker hold.
On the other hand, the finer threads on these screws mean they have less surface area to grip wood grains, which is why coarse threads work better when working with wood studs.
Drywall Screw Gauges
The third main factor when determining which type of screw to purchase is the drywall screw gauge.
Gauge is a fancy word that simply refers to the diameter of the sheetrock screw.
For the majority of applications, #6 or #8 drywall screws are going to be used. It’s important to keep in mind that, unlike some other construction materials, drywall screws get thicker when the numbers get higher. Therefore, a #8 drywall screw is thicker than a #6.
The actual diameters of the screws are:
- 0.138 inches for #6 screws
- 0.164 inches for #8 screws
Different gauges are used for different-sized studs. In the case of drywall screws though, it should be fine to use either #6 or #8 screws in most applications.
When looking to purchase sheetrock screws, the gauge is often listed as a number after the screw length. For instance, a 1 ¼-inch screw with a #8 gauge might be listed as “1 ¼-inch x 8.”
Another option for drywall and sheetrock screws is to use stainless steel. These screws are much tougher because of their high tensile strength and high corrosion resistance. Stainless steel sheetrock screws also have high creep rupture strength because of the added chromium and nickel to the allow. This additional strength might make stainless steel sheetrock screws a better choice.
There are also black drywall and sheetrock screws, which have a black phosphate coating that keeps the wet drywall compound from rusting the screw head.
Other Drywall Screw Terminology
The above three factors are the main pieces of terminology that you’d likely run into when learning about sheetrock screws.
Delving into the terminology and features of drywall fastening can be overwhelming at first, but as shown above, understanding drywall screws isn’t too complicated.
However, you may have seen some other terms like “sharp point” and “bugle head” which are just as easy to understand.
Bugle Head Sheetrock Screws
Drywall screws called “bugle screws” or “bugle head screws” refer to the shape of the screw’s head which is specifically designed for drywall application.
The bugle head design distributes stress over a much wider area than flat-head screws are able to by creating its own countersunk hole when screwed in.
Basically, the bugle head is great at securing the screw in place without tearing up the drywall paper and is great at being screwed flush with the material itself.
Sharp Point
“Sharp point” can seem like a redundant term for a screw since most do come to, well, a sharp point.
However, screws that specify they have a sharp point refer to their ability to self-tap. “Tapping” or a self-drilling drywall screw refers to initially piercing a material, like a wood stud, to give a screw a starting point to drill into.
Sharp point and self-tapping, or self-drilling screws have sharper points, making it much easier to stab into the drywall and get started for a quicker and more secure connection.
Using Sheetrock Screws
With a rudimentary understanding of the features of drywall screws locked down, the struggle now is understanding what type of drywall screws are used when and how many screws are needed for use.
The majority of drywall is sold in 4×8, 4×10, or 4×12 foot panels or sheets which are then secured into wooden or metal studs. Wall studs in homes are usually set 12 to 16-inches apart, so for securing a 4×8 drywall sheet against wall studs, you’d need on average 28 screws. You will always want to refer to your local building code for proper screw patterns and requirements, along with the project’s specifications.
How Many Drywall Screws to Purchase
Because you need a specific amount of screws to safely and securely fasten drywall to studs, purchasing the correct amount of screws is key. However, it can be frustrating to figure out how many drywall screws to buy since they are often sold by the pound.
When purchasing by the pound, the exact number of screws contained is never explicitly said, but there are decent estimates out there:
- For 1 ⅝-inch coarse thread #6 screws, there are about 200 screws per pound.
- For 1 ¼-inch coarse thread #6 screws, there are about 238 screws per pound.
A general rule of thumb is that screws get heavier the longer they are and the higher the gauge they have. Longer, higher gauge screws will have fewer screws per pound, so make sure you get enough drywall screws.
What Kind of Drywall Screws to Use
Different types of sheetrock screws are better utilized in different places. As noted above, coarse-thread screws are best used when working with wooden studs. Fine thread drywall screws work best with light metal studs.
Depending on the type of project, either ½-inch drywall or 5/8″ drywall sheets are used so 1 ¼ or 1 ⅝-inch sheetrock screws should be used. These lengths can safely and securely tap through ½-inch or 5/8″ thick drywall with plenty of room to secure themselves inside a wall stud.
The longer the screw or fastener is, the more secure the hold, but the harder it is to drive into the wall. The 1 ⅝-inch sheetrock screw may be a difficult screw to embed since over an inch remains after going through the initial ½-inch of drywall.
The last ¼-inch to ⅛-inch of a drive is critical since the head of the drywall screw needs to crease the drywall paper and embed itself flush. The shorter the drywall screw, the easier it is to align this final drive. But if you drive the screw into the drywall too deep, it will fail to stay securely fastened to the wall.
When To Use and Not Use Drywall Screws
Drywall screws are mainly used when screwing sheets of drywall into wall studs. In this setting, sheetrock screws have become the primary fastener. However, drywall screws have a narrow range of functionality and should only be used for certain projects.
Drywall screws work great with softwood studs, coarse threads granting great grip to the wood grain. Drywall screws can be used for lighter building projects like building cabinets, so long as safety is not a big factor.
Safety being a factor is critically important because drywall screws are relatively brittle compared to other types of construction screws. While other regular screws and nails tend to bend, drywall screws are liable to snap. The heads of drywall screws are especially prone to this. While it’s possible to extract bent nails or screws, there’s no way to remove a snapped-off drywall screw shaft from wood boards without pliers, or cutting the screw.
For this reason, drywall screws should never be used for heavy or even moderate building tasks. They should not be exposed to the elements like water or snow, critically never to be used when making outdoor projects like decks or fences. You will want to use a specifically designed deck screw or fence screw for those tasks. Don’t use drywall screws for handrails or stairs as these are weight-bearing functions for which sheetrock screws are not designed.