Fasteners

Fastener assembly and designation

Designation

Designation example 14 – 10 x 20 HG means 14 gauge, 10 threads per inch and 20 mm in length measured from the underside of the head to the point of the screw. Screws to have HiGrip thread.
Note: Screws can be specified with or without the HiGrip thread option.

Buildex® Metal Teks

Fixing Roofing and Wall Cladding to Metal

TEKS® self-drilling screws have a hardened drill point that will drill and thread in structural steel and mild steel.

To choose the correct fastener it is necessary to select one where the length of the drill point is equal to or greater than the total thickness of the material to be drilled, and the table below gives the thickness limitations for each screw. The length should allow three threads to protrude beyond the metal being fastened to.

Taptites® require pre-drilled holes into which the fastener will thread.

Buildex® Type 17

Fixing Roofing and Wall Cladding to Timber, or Stitching Sheetmetal

Type 17’s are self-drilling screws for fixing into timber and thin metal thicknesses up to 0.6mm. To use the correct fastener, the screw length should be chosen to achieve the minimum amount of embedment given in the table below.

Buildex® Roofzips

Roofzips® are a revolutionary self drilling roof fastener that can be used into all types of timber, and steel purlins up to 1.5mm thick. Its improved drill tip starts quicker into the metal, overcomes skidding and scratching of the screw, as well as reduces washer damage. Incorporates HiGrip, to stop the roof moving down the screw shank, and ShankGuard to protect the fastener shank from scratching during fixing. Only available in the superior Climaseal 4® coating for use in moist areas up to Severe Marine.

Material Grades

Buildex® fasteners are available in a finish that complies with AS3566, and are made to a high standard of quality backed by strict inspection and testing procedures endorsed to ISO 9002.

Climaseal 4®

Climaseal 4® fasteners meet and exceed the AS3566 Class 4 specifications. Climaseal 4® is a unique coating system comprising of an alloy combination which gives exceptional galvanic protection. The coating thickness exceeds 50 m, which is twice the thickness of a lesser Class 3 product.

1. A mechanically deposited zinc alloy coating giving excellent galvanic protection.
2. A chromate conversion coating to passivate the zinc alloy, further inhibiting coating loss.
   
3. An aluminium filled polyester coating with good all-round corrosion and long-term weathering resistance.

Climaseal 4® should be used in all areas including coastal areas where salt, wind, UV and moisture are prevalent, in tropical zones, in industrial zones subject to acid rain fall-out, where agricultural spraying is carried out, or anywhere high-performance cladding material is specified.

Effective sealing of roofing sheets/cladding and reduced corrosion with an improved black non-conductive EPDM seal. The black seal remains elastic in temperature extremes, and will not break down and allow water entry.

It is particularly recommended for use in moderate and severe marine environments.

Category 5 screws

Extra coating applied to the screw offering superior corrosion performance with increased durability allowing for use in a category class 5 severe marine in accordance with ISO9223: 2012.

Available only on a few of the screw range and sizes.

Buildex® Stainless Steel

Buildex® has a comprehensive range of stainless steel fasteners available in the following grades:

Grade 304

This is the basic composition of Austenitic Stainless Steel. Overall corrosion resistance is rated Excellent. Has the ability to withstand ordinary rusting, resists nitric acid well, sulphur acids moderately and halogen acids poorly. The Buildex® range consists of:

Type 17’s

Developed to self-drill through long-life corrosion resistant panels into timber where a highly corrosive environment exists. The drilling point is designed to drill its own hole through various aluminium and steel roofing and cladding sheets and secure into timber in one simple operation.
Available in a Hexagon Head or a Countersunk Head where a flush finish is required.

Taptites

Thread rolled fasteners for fixing long-life roofing and cladding sheets to steel or aluminium. Ideal for jobs where the thickness of material prevents the use of self-drilling fasteners. Taptites produce their own mating threads to ensure greater contact and a tighter fit.

Stitch Screw

Ideal for joining light gauge metal such as gable trim and parapet flashing.

Grade 316

An Austenitic Stainless Steel, commonly known as marine grade, is required where submergence in salt water, or direct contact in severe environments will occur.

Buildex® Type 17’s and Taptites are available in Grade 316 – but only made to order (minimum quantities may apply).

Alutite Aluminium Type 17 Hex Head Screws

Designed for fixing aluminium roofing and cladding into timber in severe marine environments. Supplied with neo seals only or a 14mm diameter aluminium and an EPDM bonded washer, which is compatible with aluminium roofing and cladding. Material: AA 2024 Aluminium (SS 4338).

Buildex® HiGrip

HiGrip from Buildex® is a revolutionary design in roof fasteners that overcomes the traditional problems with crest fixing metal roofing to steel or timber.

When roofing screws are placed on the top of the roofing profile prior to installation, an indent area sometimes forms around the screw due to the operator forcing down heavily before drilling commencement. When the profile is fixed down with a non- HiGrip fastener this indentation remains around the fastener, causing water entry.

HiGrip is a secondary thread located at the top of the shank under the washer face. During installation the thread of the HiGrip is carrying the roof profile in an upward motion while the washer face is carrying the fastener in the downward motion. The upward pressure at the HiGrip tends to straighten or reverse the indent made by the initial penetration, therefore preventing the possibility of water entry.

For strength properties see section 2.2.3.1.4 of Technical Manual

Washers

Profiled washers match the rib shape and fit over the ribs of the roofing profile. They are used for two purposes.

1. To provide an acceptable area of seal around the oversize holes drilled in the sheet material to allow for thermal expansion of the sheet (refer Section 2.1.3.4).
   2. To provide load-spreading capability at the fastener point when sheet material is used under high load or long span conditions that cause the load per fastener point to exceed guidelines given on the profile.
   
   

To fulfil either or both of these functions the recommended washer components are:

• Dimond profiled metal washer – pressed from 0.95mm Zincalume® or 1.2mm aluminium and painted for colour match and corrosion resistance if required. Each sheet profile has a specific profiled washer.
• EPDM (ethylene propylene diene monomer) seal washer – round seal used to fit all sheet profiles. Available in 19mm, 25mm and 36mm diameters for use under profiled washers. Manufactured from EPDM type rubber. It is important for the long term durability of the Zincalume substrate that the carbon black fillers in the sealing washers and neo seals contain less than 15% by volume or 25% by weight of carbon. All washers and neo seals supplied by Dimond meet this requirement.

Use of other washer components may be satisfactory, but their suitability for use must be checked against the two criteria above.

Round Washers

Dekfast round embossed washers (with the seal incorporated with the washer) are primarily used on wall cladding to provide:

1. An acceptable area of seal around the fixing screw to allow for thermal expansion of the sheet where fixed in the cladding pin.
2. Load spreading capability at the fastener point of the cladding material when fixed in the pan under high load.
3. Available in 19mm and 25mm diameter.

Decking Clips - Double

Used to secure decking profiles such as Dimondek 300 and Dimondek 400 by pushing the profile down onto it until it clicks into place. The clip is fixed onto the roof structure with either 2 wafer head screws or 2 nails. Refer Section 2.1.4.7 (b) of Technical Manual.

The double clip is designed to fix over the previously laid male under rib and centre rib of the sheet to be laid.

Clip Material

Usually manufactured from either

1. As standard unpainted 1.15mm thick coil with galvanised coating to 275 g/m2. Or;
2. Coated for increased durability. Nylon coated over galvanised. Colour may vary between Bright blue or light grey depending on supply. During a salt fog test after 2000 hours this coat showed no sign of degradation. Must be used with Aluminum roofing. Or;
3. Other material, such as brass clips to suit a copper roof, can be manufactured to customer order. The brass is 1.2mm thick
   and is 1/2 hard brass.

Continuous Clips

The innovative continuous metal strip with plastic clip is 1 sheet wide and holds 3 ribs of Dimondek 630 down.
It is interlocked with the previously laid clip, thereby controlling the sheet creep and avoiding an increase in profile cover width.

The Dimondek 630 perimeter clip must always be used over the last rib and clip on the last laid sheet, or on any part of the roof where wind loads exceed 1.6 kPa.

Used only with the Dimondek 630 profile, the clip is screw fixed onto the roof structure after laying and interlocking with the previous clip. This also allows the building paper to be secured, prior to the laying of the roof. The roof profile is then fully pushed down and locked on to the clip and previously laid sheet.

Available as standard: unpainted AZ150g/m2 Zincalume coated steel base with black glass reinforced nylon plastic clip.

Tee Bolt Assembly

Used for fixing Dimondek 300 and Dimondek 400 to the underside of the structural roof members. Typically Universal Beams.

Components

1. A stainless steel Tee bolt; produced from 5mm diameter stainless steel rod welded to form a Tee shape. The longer vertical leg is threaded for approximately 30mm.
2. A stainless steel 3mm thick strap x 25mm wide with 6mm diameter hole, used to secure bolt to the roof structure.
3. One 5mm diameter stainless steel locking nut and washer.
4. Two neo seals to fit over Tee bolt used to seal between the roofing and strap.