What are self-tapping screws used for? BDN Fasteners shall explain 2 different types of self-tapping metal screws and what are self-tapping screws used for.

What is a Self-tapping Screw? What are Self-tapping screws used for?

To begin with, self-tapping screws, as its name suggests, is a screw capable of tapping threads and securing various types of materials such as wood, metal, plastics, drywall, bricks, cement and so on and so forth.

 

It is not to be confused with self-drilling screw in that self-tapping screws usually come with a pointed tip instead of an integrated drill bit, meaning that while being able to drill through thin gauged metal sheets, though on thicker material, it normally requires pre-drilling a pilot hole.

 

 

2 Different Types of Self-Tapping Screws

Self-tapping screw threads come in two different types: forming or cutting.

 

Thread-forming means that threads are formed over the course of drilling into the material, with softer materials such as plastics being the most common.

 

Thread-cutting types are mostly used on metal, wood, bricks; which requires threads to “cut” into the harder material for an adequate fix.

 

As with all screws, especially ones that self-tap threads onto material, it is imperative to not apply too much pressure during the process, and take extra care to follow the same track when disassembling or re-assembling the screws to avoid stripping.

 

What are Self-tapping screws used for?

What are self-tapping screws used for you may ask? Although self-tapping screws usage varies from country to country, they are mainly used for securing single or double layers of thin gauge sheet metal (which is the reason why people also call it sheet metal screws), fixing brackets into wood, fastening aluminum sections to each other, drilling into plastic housings or plastic plugs.

 

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In light of recent rumors from certain companies declaring affiliation

with Tai-One Enterprise or BDN Fasteners®, we hereby announce:

• Tai-One Company is the sole authorized agent and distributor of BDN Fasteners® in Thailand and in no way affiliated with other brands and products.

 

• BDN Fasteners® is a trademarked brand in both Taiwan and Thailand.

 

• All of the BDN Fasteners® branded products sold by Tai-One Enterprise are manufactured, packed, quality checked, and imported directly from our factory in Taiwan.  BDN Fasteners® Taiwan holds all of the patents, intellectual property rights and export records to be provided upon request should the need arise.

 

• All BDN Fasteners® goods imported by Tai-One Enterprise are legally compliant with the Thailand import rules and regulations; while all sales and services are VAT invoiced and provided to customers.

 

We thank you for the trust and support of Tai-One Enterprise and BDN Fasteners®. Kindly call us for more information and verification should you hear any rumors that differ from this announcement.

 

Tai-One Enterprise & BDN Fasteners® hereby declare the above information are true and correct.

 

Tai-One Enterprise & BDN Fasteners – DECLARATION

Rust, the most feared phenomenon and common enemy among builders and owners alike of any building structure, especially ones that are exposed to the elements.  For coastal areas, salt haze formed by evaporation of sea spray corrodes and weakens the structure and also roofing screws.  In other areas, corrosion may result from acids spread from industry, vapors from agricultural fertilizers or pesticides, fumes from petrochemical sites, UV ray exposure, and humidity. Metal roof screws rusting will have negative impact on buildings regardless of its root cause of failure.

 

The cause and effect of metal roof screws rusting.

When it comes to metal roofing and wall cladding, manufacturers have put in lots of effort in the development of coatings and layering technologies to enhance weathering resistance; some even have up to five layers of coatings, each with its own unique properties to cope with severe environment, and warranted up to 50 years.

 

A very important aspect that the majority fail to realize is, these roofing sheets will live up to its projected life expectancy only if the screws and accessories used alongside them performs equally well. The overall lifespan of the metal roof covered area depends on whether there are metal roof screws rusting or not. One of the main reasons oftentimes we see really high-tech metal roofing sheets that are fixed with screws that offer little to no weathering resistance at all, which totally negates the purpose of using these high corrosion-resistant sheets in the first place.  A responsible roofing sheet salesperson should specify the type of screw with matching weathering resistance when making sales.

 

The majority of metal roofs are fixed with exposed fasteners, as opposed to concealed fixings roof where the fasteners are covered against the elements; being exposed means that fixings are the first thing that comes into sight when looking over rooftop, and any sign of rust awfully visible, though it is generally overlooked and often not dealt with until it’s too late and damage has spread to the roof sheet or even inside the building.

 

How to prevent building damage caused by metal roof screws rusting?

We suggest biennial inspections in coastal, high humidity, or highly polluted industrial areas, and quinquennial inspections in rural, less polluted areas.  Have an experienced builder or technician examine the site in question alongside you, as they should provide expert opinion on whether the rust is an immediate threat that requires replacement of the fasteners asap, or could be held off until the next season or renovation.

 

Since having metal roof screws rusting or not is detrimental to the safety and life expectancy of the building, if upon inspection, the roofing screws are really rusty, and the threat of damage imminent requiring immediate action; the following steps will guide you to choosing the correct corrosion resistant screw category for the job.

• Understand your environment. For example, areas close to the coast will be at high risk to corrosion due to high salt content in the atmosphere compared to the inland, and therefore would require high weathering resistant fasteners on structures.
• There are multiple choices on the market when it comes to corrosion resistant coatings, and products are normally priced according its service life and warranty terms and conditions.
• Since it is impossible to tell from the naked eye how effective the coatings really are, a reputable company will provide accredited 3^rd party test lab reports as proof of compliance.

 

 

For more information on metal roof screws rusting, corrosion resistance and service life in relation to the environment the fasteners are used in, kindly contact your local BDN Fasteners distributor or salesperson, or simply click on Choosing the correct screws for metal roofing sheets installation to understand the scope of warranty for our products and the environment category classification they are base upon. Choose the correct screws to prevent the building impact from metal roof screws rusting.

 

Learn more about roofing screws >>
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5 types of metal roofing: type, structure, environment. It is important to understand before selecting screws for your type of metal roof installation.

The majority of BDN self-drilling screws are designed for either metal roofing or wall cladding installations, with the exception of proprietary designs for specific purposes such as PolyXpand™ for plastic skylight fixings, or TRUSS-Tite™ for joining truss components on steel framing.

 

Common issues we see on high quality, expensive metal roofing sheets fixings are:

1. Incorrect selection of screws, with issues ranging from length, drilling capacity, thread type, gasket, and more.
2. Poor quality screws which are unfit for the location and environment installed in.
3. Improper screws for metal roof installation – the majority of issues stem from insufficient knowledge of the product, not following installation guides and instructions, and most of all, carelessness. Don’t forget that choosing the correct tool for the job also plays an important part in proper installation.

 

 

How to choose screws for metal roof installation properly?

Before any installation, understand the type of structure, material, and environment we are dealing with. Since we are talking about screws for metal roof installation, determining the type of metal roof will be first priority.

 

1. Is it a single sheet insulated panel?
2. Are there any skylight panels installed in between sheets, and if so, what type of material are the skylights?
3. What is the thickness of the sheet, and how thick is the insulated portion underneath?
4. Color of the sheet and should the screws have to come with matching head colors?

 

Understanding the type of metal roofing and structure type

Upon determining the type of sheet used, we then have to understand the type of structure it is affixed to.

1. Are the purlins steel or timber?
2. Thickness of the steel purlins?
3. Are there any trusses involved?

 

Introduction to the 5 environmental classifications

We should then determine the kind of environment the building structure is built on.  Here at BDN Fasteners, we have categorized the kind of environments to the following based on its characteristics.  Scope of warranty for our products are also based on the category the environment is classified to.

Dry, Rural Areas –

• Areas remote from the coast and sources of pollution; as well as all of the areas listed below.

Mild Urban or Rural Areas –

• Areas with little to no chemical pollution, including but not limited to natural chemicals such as ammonia from livestock or carbon monoxide from log-fire.
• Areas far from the coast with no impact from salt water spray.
• Areas at least 2 kilometers away from any type of industry, light or heavy.

Light Industrial or Urban Areas –

• Light industrial zones, light manufacturing, warehousing, distribution, or limited light intensity activity areas.
• Built up areas constituted of high human population and infrastructures.
• Areas at least 1~2 kilometers away from light industrial or urban areas.

Small Industrial Zones –

• Areas located in or adjacent to small industrial zones.

Coastal Areas –

• Areas located approximately 2 kilometers from the coast.

 

 

Lastly, choosing the correct screws for metal roof installation is only half the job done, and it all comes down to how the installer completes the final touch, as an improperly installed screw is worse than none installed at all.

 

Above are basic guidelines for the novice builder or contractor to follow when making the correct fastener selection.   Since building sites differ from one another, additional factors may be required to take into consideration; it is best to contact an experienced salesperson or technician for on-site checks before making final decisions.

 

Learn more about BDN Fasteners >>
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Self-Tapping and Self-Drilling screws are the bread and butter of our business and the most commonly known and used for fastening two different kinds of material, be it steel, timber, or plastic, and the list goes on.

BDN Fasteners offers TIMBER-Tite™ and TRUSS-Tite™ self-tapping screws.

TIMBER-Tite™ screws are designed for fixing metal roofing sheets or wall claddings to timber, whereas TRUSS-Tite™ is designed to fix steel roofs and floor trusses. Basically, all self-drilling and self-tapping screws are able to tap threads, where the main difference is that self-tapping screws normally come with either a blunt head, sharp point, or a reduced drill point.

 

Blunt headed screws such as the TRUSS-Tite™ is designed for truss components assembly, fixing into steel. These types of steel normally come with pre-punched or pre-drilled holes, and the blunt, slightly tapered leading threads makes it easier to fix the sheets down.

 

Our sharp pointed TIMBER-Tite™ are designed for fixing roof sheeting to timber. The longer versions such as the T17CG1265C3N or T17CG1250C3N are designed for crest fixing and shorter versions such as the T17H1020C3N are designed for valley fixing. People ask why screws should be fixed down on the crest but not the valley. The main reason being water runs by gravity and flows to the lowest point, and if fixed on the valleys on rooftops, might increase the risk of water pooling around the screws and with time, cause rust.

Shorter self-tapping screws which come with what we call a “reduced” drilling point, provides the same function as a sharp drilling point, but drills faster through thin metal sheeting, and is much more effective at clearing off excess swarf, as it is difficult if impossible to add flutes on smaller sharp pointed screws to due manufacturing limitations.

 

For roofing sheet fixing screws, always check if they come with a knurled, fluted, or slotted shank, and if the upper threads are larger in diameter compared to the lower threads. You might notice that the majority of BDN self-drilling and self tapping screws for metal are equipped with both. The larger diameter upper threads provide good pullout strength for the whole setup under high winds and the slotted Scratshank design clears out excess swarf which might damage EPDM washers if leftover, which could result in leaks.

 

Learn more about BDN Fasteners >>

Internal Roof Insulation Installation with Self-Drilling Fasteners
How to use self tapping screws for metal?