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FAQ – Questions and answers
The most common questions in construction
BDN FASTENERS® Exclusive dealer, distributor and sales offices – Worldwide.
BDN FASTENERS® Exclusive dealer, distributor and sales offices – Worldwide.
BDN Fasteners® Building Fasteners Product application
BDN Building Fasteners Product Series
BN3™ Corrosion Resistance Class 3: SST 1000 hrs + Kesternich 7 cycles
– Dual-Edge® METAL-Tite™ Self-Drilling Screws Series
– TIMBER-Tite™ Self-Tapping Screws Series
– Framing Screws Series
– Polycarbonate Roof Fasteners Series
C3 & C4 Surface Coating Corrosion Warranty
C3 & C4 Surface Coating Corrosion Warranty
The below table is an indication of the warranty period based on the corrosivity of your location and is to be used as a guide only. To determine the appropriate ISO 9223 category for your environment, please contact your local representative. Environmental conditions and category is complex and can be influenced by a wide range of factors. Note that in certain instances, corrosion zones can extend out further to what is stated above.
BDN Fasteners® has aligned the warranty period for its products to be consistent with the warranty period of major roofing material suppliers. AS3566.2 Outdoor Exposure testing results indicate the lifespan of our products to extend beyond the warranty period.
Fastener Corrosion Resistance Classification
- CLASS 3: Withstand 1000hrs Salt-Spray Test (SST) + 15 Kesternich Cycles [Condensing the atmosphere containing Sulphur dioxide (SO2) at level SW 2.0 S – Simulates acid rain or industrial chemical exposure to evaluate the relative corrosion resistance.]
- Class 4: Minimum Porosity Rating of 8 (Micrograph comparison). 45 um of 98% Zinc composition on hot-dipped galvanized coating. 25~30% of Tin balance zinc composition on Mechanical Zinc-Tin plating.
POLY-FAST Polycarbonate Fasteners Installation Procedure
POLY-FAST Polycarbonate Fasteners Installation Procedure
POLY-FAST™ roofing fasteners feature a Thermal Expansion Hole Cutter that creates a much-required thermal expansion hole on plastic profiled roofing panels, The panels are then securely fastened onto the purlin support underneath in onego.
A nominal 11mm diameter hole is created by the Thermal Expansion Hole Cutter during the process. When mated with the Thermal Expansion Hole Cutter, with the Depth Stop Knurls acts as a stopper, the height at where it stops upon coming in contact with the purlins; enough so that it prevents screw over-run or over-drive, provide a perfect seal to the enlarged hole, but not deform the corrugations. BDN Fasteners polycarbonate roof fasteners are designed to create precise thermal expansion holes for fixing polycarbonate roof sheets.
Fast Plastic Roofing Fasteners (For Timber)
Fast Plastic Roofing Fasteners ( For Steel)
4 common causes of metal roof leaks around screws
4 common causes of metal roof leaks around screws
Below is a list of common causes of metal roof leaks.
1. Choosing an incorrect screw
2. Over–driven screws
3. Under-driven screws
4. Misaligned or skewed drilling
Some screws have extra features built in to enhance performance; oftentimes poor choice of fixings become the weakest link in a seemingly strong building structure. BDN Metal-Tite® series roofing screws come with an enlarged hex washer flange, anti-static EPDM washer, double thread, Scratshank, and Ruspert anti-corrosive coating.
- The large washer flange is designed so that the EPDM washer will remain fully covered after compressed.
- Anti-static EPDM washers prevent galvanic corrosion.
- The larger diameter upper thread close to the hex washer flange increases pullout values on thin metal sheets.
- Scratshank clears out excess swarf, smooths out the drilled hole, and prevents damages to the EPDM.
- Ruspert anti-corrosive coating fully protects the screw from weathering and extends the lifespan of the screw and the sheets it is affixed to.
Eco-BDN, Green EPDM Washer Installation Guide
Eco-BDN, Green EPDM Washer Installation Guide
Building it right to make it watertight
Eco-BDN, Green EPDM Washer provide an excellent waterproof seal— even under the most severe weather conditions— if properly installed.
- The trick is not to overdrive or underdrive the screws.
- If the screw is not tightened enough, moisture leaks around the washer. An overtightened screw squishes the washer too thin, which can also result in leaks.
- Important Tip: Replace worn sockets immediately if they cause the screw to wobble during installation. Crookedly driven screws can cause water leaks.
BDN POLYXPAND™ BAZ EPDM Washer Installation Instructions
BDN POLYXPAND™ BAZ EPDM Washer Installation Instructions
BAZ EPDM washers are the ideal washers to be used on polycarbonate sheets, especially corrugated ones. With a large diameter to fully cover expansion holes to provide the perfect sea and flexibility to conform to the curvature of the skylight, but at the same time, providing enough strength against high wind situations.
However, it is absolutely critical to not drive the screw to the point that the washer is squished, which will result in the washer losing its flexibility, and a gaping hole gouged out by the hex washer flange.
Self-Tapping vs. Self-Drilling Screws: Do You Know the Difference?
Self-Tapping vs. Self-Drilling Screws:
Do You Know the Difference?
- Self-Drilling Screw – Steel Sheet / Steel Purlins
Trident Drill Point
✔ Improved Drill Performance
✔ Time Saving
- Self-Tapping Screw – Timber
Type 17 Sharp Point
✔ Reduce Splitting
Patented Trident Drill Point
Patented Trident Drill Point
The patented Trident Drill Point provides fast and
steady drill performance, effectively clears swarf,
and drills through 6mm thick steel.
“S” Swirl: Creates a larger area of engagement from the initial drill drive.
Improved “Cutting Edge” Design: Larger, curved cutting blade edge lower manual load required.
Incorrect screws create stress cracks and thus leakage on Polycarbonate or other Plastic Sheets
Incorrect screws create stress cracks and thus leakage on Polycarbonate or other Plastic Sheets
BDN Fasteners® POLYXPAND™ (Skylight Fixing Fasteners)
True Australian AS3566 Standard Hex Washer Flanged Head:
Separate EPDM steel bonded washer NOT required. (No risk of leakage)
Thermoset 100% EPDM BAZ washer:
☑Weathering Resistant (UV / Ozone / Acid)
☑100% Leak proof sealing
☑Perfect fit under hex washer flange
☑Optional metal washer add-on
☑Shock absorbing (for high wind areas)
Creates a 10mm dia:
Thermal expansion hole for plastics.
Winged Drilling Tip:
Wings break off once in contact with the steel purlins,
keeping the plastics sheets securely fastened.
BDN Fasteners Surface Coating Class
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.
BDN Fasteners – Surface Coating Class
Corrosion Resistance
- Class2 – SST 500hrs + Kesternich 5 Cycles
- Class3 – SST 1000hrs + Kesternich 7 Cycles & 15 Cycles
- Class4 – SST 2000hrs + Kesternich 15 Cycles
✓ Australian AS3566 Standard
✓ SGS Certified
True Australian Standard-AS3566
The BDN Comparison-AS3566
BDN Fasteners
True Australian Standard-AS3566
Washer Diameter=13.97-14.78mm
Scratshank
SCRATSHANK FEATURES
- Cutting / Break out the metal filings
- Remain free of damage to sealing washer during installation
- Weatherseal
Double Scratshank: Swarf Free
Double Scratshank: Swarf Free
BDN Fasteners – Dual-Tite™ (Roofing Screw Duofix 2 IN 1)
Double Scratshank: Removes sealing washer damaging swarf during installation.
Harpoon Thread: Anti-stripping, roof fixing threads
Harpoon Thread: Anti-stripping, roof fixing threads
BDN Fsateners – Dual-Tite™ (Roofing Screw Duofix 2 IN 1)
Harpoon Thread: Anti-stripping, roof fixing threads
BDN Fasteners 100% Weather Sealed
DEKS Dekseal® Trueblue® 100% Weather Sealed
BDN Fasteners – B//> Series: Silver Blue / SST 5000hrs / Kesternich 5 Cycles
- Hex Washer Flange: True Australian Standard-AS3566
- DEKS Dekseal® Trueblue® 100% Weather Sealed
- 100% Made In Taiwan
BN3 Series - DEKS Dekseal® Trueblue® 100% Leak proof sealing
BN3 Series – DEKS Dekseal® Trueblue® 100% Leak proof sealing
BDN Fasteners – BN3 Series: Silver Grey / SST1000hrs / Kesternich 7 Cycles
- DEKS Dekseal® Trueblue®: 100% Weather Sealed
- Hex Washer Flange: True Australian Standard-AS3566
- 100% Made In Taiwan
BDN Fasteners
BDN Fasteners (Broaden Worldwide Co., Ltd) is an ISO-9001 Certified Quality Supplier-Manufacturer of Australian Standard AS3566 self-drilling and self-tapping screws in various coatings for steel to steel and steel to timber applications. Our headquarters are in Taiwan and we operate sales and marketing offices in India and Thailand.
Founded in 2009.
Impact of metal roof screws rusting & how to prevent the damage
NewsRust, 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.
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 >>
Internal Roof Insulation Installation with Self-Drilling Fasteners
How to use self tapping screws for metal?
What screws for metal roofing? Tips on choosing roofing screws types
News5 Types of Metal Roofing: Type, Structure, Environment
News5 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:
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.
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.
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 –
Mild Urban or Rural Areas –
Light Industrial or Urban Areas –
Small Industrial Zones –
Coastal Areas –
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 >>
Internal Roof Insulation Installation with Self-Drilling Fasteners
How to use self tapping screws for metal?