Drywall, or gypsum board or wallboard, is a building material used to construct walls and ceilings in residential and commercial buildings. It is made of gypsum, a soft sulfate mineral composed of calcium sulfate dihydrate sandwiched between two sheets of heavy paper or fibreglass. Drywall is widely used because of its ease of installation, durability, and fire resistance. It is available in different thicknesses, from 9mm to 25mm. The main benefit of drywall is that it is relatively cheap and easy to install. It can be cut to size using a utility knife and attached to wood or metal framing using drywall screws. Unfortunately, there are loads of different types of drywall screws, so in this blog, we are going to try to explain the difference between them so you know which ones to use on your next job!
Zinc Coated Drywall Screws versus Black Phosphate Drywall Screws
Zinc-coated drywall screws (often referred to as BZP drywall screws) are screws that have been coated with a layer of zinc to protect them from rust and corrosion. Black phosphate drywall screws are screws that have been coated with a black phosphate finish.
The main difference between the two is the type of coating used. Zinc coating provides a higher level of corrosion resistance than black phosphate coating, but black phosphate coating provides a better grip and can be more visually appealing. Additionally, black phosphate coating is generally less expensive than zinc coating.
Why use Black Phosphate drywall screws
Black phosphate drywall screws are used for a variety of reasons, including:
- Aesthetics: The black colour of the screws can blend in better with the surrounding surface, making them less noticeable.
- Grip: The black phosphate coating provides a better grip than zinc coating, which can make it easier to drive the screws into the drywall.
- Cost: Black phosphate coating is generally less expensive than zinc coating, making it a more cost-effective option.
- Resistance: The black phosphate coating provides a moderate level of resistance to corrosion, making it suitable for indoor use.
- Compatibility: Black phosphate coating is compatible with various materials and substrates, making it versatile.
Why use Zinc Coated Drywall Screws
Zinc-coated drywall screws are used for a variety of reasons, including:
- Corrosion resistance: Zinc coating provides a higher level of corrosion resistance than black phosphate coating, making it a better option for outdoor or high-moisture environments.
- Durability: Zinc coating is known to be more durable than black phosphate coating, which can make the screws last longer.
- Aesthetics: Zinc coating can be used to match the colour of the surrounding surface, making the screws less noticeable.
- Compatibility: Zinc coating is compatible with various materials and substrates, making it versatile.
- Cost-effectiveness: Although zinc coating is more expensive than black phosphate coating, it can be considered a cost-effective solution in the long run because of its corrosion resistance and durability.
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Screw spacing guide
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Fine thread Drywall screws versus coarse thread drywall screws
Fine thread and coarse thread drywall screws are different in terms of the thread pitch, which is the distance between the threads on the screw. Coarse thread drywall screws have a wider thread pitch, meaning the threads are farther apart. This makes them better for gripping into softer materials like drywall, and they are typically used for attaching drywall to wood studs. Fine thread drywall screws have a narrower thread pitch, meaning the threads are closer together. This makes them better for gripping into harder materials like metal studs, and they are typically used for attaching drywall to metal studs or other harder surfaces.
In general, coarse thread drywall screws are considered to be stronger than fine thread screws, and they can provide a more secure grip in wood. On the other hand, fine thread drywall screws are considered to be more precise and accurate, and they can be less likely to damage the material they are being driven into. In summary, the choice between fine or coarse thread drywall screws depends on the type of material you will be attaching the drywall to and the level of precision and grip you require.
What is a Bugle Drywall Screw?
A bugle drywall screw is a type of drywall screw that has a unique head shape known as a "bugle head." The bugle head has a wider, flatter surface than a traditional drywall screw, which allows it to sit flush against the surface of the drywall. This design helps to prevent the drywall from cracking or splitting when the screw is driven in and allows for a smoother finish.
Bugle head drywall screws are typically used in conjunction with drywall anchors and are inserted into the drywall, and then the anchor is inserted into the hole created by the screw. The screw is tightened, pulling the anchor flush against the back of the drywall. This creates a strong and secure hold without locating a stud.
Another advantage of using bugle head drywall screws is that the bugle head provides a larger bearing surface, which distributes the clamping force over a larger area and reduces the chance of the drywall cracking or breaking.
In summary, bugle head drywall screws are used to attach drywall to wood or metal studs or to other materials using anchors. They are designed to sit flush against the surface of the drywall, preventing cracking and providing a smooth finish.
What are Collated Drywall Screws?
Collated drywall screws are attached to a strip or sheet of material, known as a collation. The collation keeps the screws in a specific order and spacing, making them easier to handle and use. Collated drywall screws are typically used in conjunction with a collated screw gun, which is a power tool that automatically feeds the screws from the collation into the gun, allowing the user to drive the screws quickly and easily into the drywall. This can be especially useful for large drywall installation projects where many screws need to be inserted in a short period of time.
Collated drywall screws come in a variety of lengths, thread types, and head types. They are available in various packaging, like strips, coils, or plastic cases. They are also available in different types of collation, like paper, plastic, or wire coil.
The main advantage of collated drywall screws is that they allow for faster and more efficient installation of drywall, as the user does not need to manually handle and place each individual screw. Additionally, collated drywall screws are less prone to dropping or losing screws, which can save time and reduce the risk of injury. In summary, collated drywall screws are attached to a strip or sheet of material called a collation, designed to be used with a collated screw gun. They allow for faster and more efficient installation of drywall and reduce the risk of losing or dropping screws.
Optimum Length of Drywall screws
The optimum length for a drywall screw in millimetres (mm) depends on several factors, including the thickness of the drywall, the type of material the drywall is being attached to, and the desired level of grip.
For attaching 12.5mm (1/2") drywall to wood studs, a 32mm to 38mm long drywall screw is generally considered to be the best choice. This length allows the screw to grip securely into the stud while not penetrating through the other side of the drywall.
For attaching 15.9mm (5/8") drywall to wood studs, a 44mm to 51mm long drywall screw is generally considered to be the best choice.
For attaching drywall to metal studs, a 32mm to 38mm long drywall screw is generally considered to be the best choice.
When using drywall anchors, it is recommended to use 32mm to 38mm long drywall screws. As a reminder, it is always better to use slightly longer screws than shorter screws, as longer screws provide a better grip and are less likely to pull out over time.