• design • material • conductivity • traceability • tear strength • warranty
In Australia, New Zealand, South East Asia and Europe, Deks quality roofing washers are chosen by major fastening suppliers to ensure their fastening suppliers to ensure their fasteners provide a weathertight seal against wind, rain, heat and sunlight.
But aren't all washers the same? an expensive assumption!
Because washers are small and relatively inexpensive, their importance in a roofing project is sometimes overlooked. However, a poor quality washer can result in enormous costs if it is badly designed or made of inferior material.
 With 4.5 fasteners per square metre of roofing sheet, washers play a significant role in any roofing project.
Early breakdown of the washers will result in, at best, the replacement of all screws and seals across the entire roof, and at worst, considerable water damage to the building. The washer is vital in maintaining the integrity of the roofing system.
DEKS washer design ensures sealing at ALL points of contact between screw and roofing sheet. The illustration below shows how the DEKS metal backed washer range, Dekfast® Multi-Seal™ has a clear advantage over conventional washer designs.
Dekfast Multi-Seal
Protects and seals under the head (1), against the shank (2), against the roof sheet (3) and around the perimeter (4). |
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Non-DEKS bonded metal washer
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Normally hidden from sight, a cross section shows how basic washers rely on ineffective metal to metal contact, which can never guarantee100% effective waterproofing. |
The least costly product can be the most expensive if it fails
Although washers tend to look the same , chemical analysis shows that their performance differs dramatically. Only a premium EPDM compound is suitable for use on metal roofs, particularly if the washer and fastener are powder coated and baked after assembly.
All black washers are NOT the same - even when they look identical.
Carbon black added to the washer material provides important qualities such as UV and ozone resistance, but too much can create corrosion problems by creating an electrical pathway between the roofing sheet and the screw. Carbon black is often over-used in EPDM compounds by manufacturers because it is cheap. DEKS have achieved just the right threshold level of carbon black that eliminates conductivity in their Dekseal® TrueBlue® range. Dekfast® Multi-Seal™ washers are supplied non-conductive as standard, but conductive formulations are available when electrostatic powder coating processes require it.
Bluescope Steel - Setting the Benchmark for Best Practice Roofing
Bluescope’s TB-16 warns that the quantity of carbon black in a washer is critical, as it can form a ‘corrosion’ pathway, particularly on ZINCALUME® zinc/aluminium alloy coated and COLORBOND® prepainted steel products.
We have found that DEKS black EPDM washers exhibit exceptional levels of performance and provide complete compatibility with BHP Colorbond and Zincalume coated steels. ..... a controlled level of carbon in this product provides
Udo Buecher, Senior Principal Research Engineer. BHP Research
DEKS is the only manufacturer with the confidence in their products to offer full traceability across their entire washer range. According to the Australian Standard AS3566:2002-1, fasteners of size 4.8mm diameter and larger are required to carry a ‘unique identification mark’ that denotes a) the class of coating and b) the manufacturer. This allows all roofing fasteners to be recognised as carrying a certain level of corrosion resistance and in the event of a problem, traced back to the manufacturer.
Your only assurance of a quality product is the ability to trace it back to the manufacturer.
The right balance of hardness, tear strength and compression performance determines how well a cut washer assembles, compresses and resists the tearing effects of swarf, and keeps the screw sealed throughout its life on the roof.
Washer Integrity and Exposure to Heat
Washers from materials other than EPDM will quickly breakdown on the roof as temperatures climb in the heat of the day. Research shows that on a 23 degrees C (73 degrees F) day a metal roof temperature can climb to 85 degrees C (185 degrees F).
It is important to realise that high heat affects tear strength.
If a washer has been through a powder coating process it will have been exposed to temperatures of 220 degrees C (428 degrees F) for 20 minutes or more. The table below demonstrates the impact on different brands of cut washer as we simulate a typical powder coating process.
Every DEKS washer carries a 20-year warranty, is traceable and meets the rigorous metal roofing standards established in conjunction with companies such as Bluescope Steel, Corus and Butler. DEKS recommends that consumers and fastener manufacturers ensure that the washer they purchase complies with industry standards and supports the life and integrity of the roofing system. A further assurance of quality comes from our IS0 9001 Benchmark certification.
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