TEKS

Self Drill and Tap Screws

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 The self drill & tap screw name of Tek came from the Buildex company's name for their own brand of self drill and tap screws, which has now become the generic name for them.

These fix in the valley screws with their ease of fixing were a revolution in the roofing industry and have now almost totally replaced the traditional bang a big nail through the top of the profile brigade. With them have come many variations to meet the particular requirements of different  materials and circumstances.

Early Tek screws were made with a 3/8 head (10mm). The use of this size has now almost ceased in favour of the small 5/16 head (8mm).

FIXING The screws must be fixed at a 90% angle to the sheet and tightened down until the fibre washer shows slight bulging, over tightening can be as bad as under tightening. Large contractors use specialist equipment for fixing these screws. On small contracts electric drills with a socket attachment are used. They MUST have a speed control and a torque control is also advisable for both correct tightness and safety, otherwise sprained or broken wrists are likely to be incurred. Specialist tek guns (electric drills) can be hired from good tool hire companies.

IMPORTANT. If fixing Aluminium or Stainless Steel sheets, Stainless Steel Teks MUST BE USED. In coastal regions subject to salt spray and industrial corrosive environments, the use of Stainless Steel Teks is also advisable.

The quality of tek screws can vary between makes. SLE Cladding Ltd only stock and supply screws from well known quality manufacturers. Below we illustrate some of the many types that we stock and their usage.

For fixing profile metal sheets to timber purlins. Popular sizes are 25mm and 40mm long. The 40mm is normally recommended for secure fixing. Other sizes are available to order.

For fixing profile metal sheets to timber purlins. The gash point makes the initial penetration of the metal sheet slightly easier than with the type AB above. Popular sizes are 25mm and 40mm long. The 40mm is normally recommended for secure fixing. Other sizes are available to order

For fixing profile metal sheets to cold rolled galvanised Z purlins or other relatively soft metal structures. Note the drill bit point and the course threads. Popular size is the 51mm length. Other sizes are available to order.

For fixing profile metal sheets to thicker steel structures, such as angle iron, box iron and H beams. Note the better quality long point drill bit and the finer securing threads. Popular sizes are 32 and 51mm lengths. Other sizes are available to order.

 NOTE. All angle iron is not of the same quality (particularly old angle iron). Some contain more nickel than others and is thus a harder steel. This may occasionally result in the head shearing off the screw before it has drilled through the angle iron. The only time consuming  remedy is to pre-drill with a smaller sized conventional metal drill bit.

For fixing profile metal sheets to timber purlins through insulation materials including composite panels.

Note the threads immediately beneath the fibre washer, these are designed to pickup and hold the top sheet in position, otherwise under snow, wind or other loading, the top sheet may slide down the fixing as the insulation compresses under the pressure, breaking the seal. Available in a range of sizes to meet varying insulation thicknesses

For fixing profile metal sheets to cold rolled galvanised Z purlins or other relatively soft metal structures. through insulation materials including composite panels.

Note the threads immediately beneath the fibre washer, these are designed to pickup and hold the top sheet in position, otherwise under snow, wind or other loading, the top sheet may slide down the fixing as the insulation compresses under the pressure, breaking the seal. Available in a range of sizes to meet varying insulation thicknesses

For fixing profile metal sheets to thicker steel structures, such as angle iron, box iron and H beams through insulation materials including composite panels. Note the better quality long point drill bit bit and the finer drilling threads.

Note the threads  immediately beneath the fibre washer, these are designed to pickup and hold the top sheet in position, otherwise under snow, wind or other loading, the sheet may slide down the fixing as the insulation compresses under the pressure, breaking the seal. Available in a range of sizes to meet varying insulation thicknesses

STANDARD TEKS FOR FIBRE-CEMENT SHEETING

Illustrated is the standard point for use with cold rolled Z purlins.

Also available as type AB for timber purlins and as "Stand Off"  in various lengths for use with insulation materials.

These large tek screws are expensive to purchase, but the vast amount of time and labour cost they save when compared with the use of the traditional Hook or Crook Bolts makes for a considerable cost saving overall.

 Mini Tek screws with a standard drill point, for side stitching profiled sheets and attaching Ridge Sheets, Barge Sheets and Flashings to profiled sheets etc. 5/16mm head, (8mm) 16 mm washer, length 20mm

For side stitching GRP Rooflights in exposed areas they are available with the larger 29  mm washer.

The standard point without a washer is used mainly when sheeting box iron doors and tubular gates as well as any other fixing application where a watertight seal is not required.

Used for any application involving wood where a watertight seal is not required. Example fixing gutter brackets to timber Eaves Beams.

These early type B Teks with a blunt end require a predrilled 4.8mm hole and are little used these days. They are mainly used in circumstances were the steel girder etc is too thick or to hard for a conventional self drill tek to drill.

SLE Cladding Ltd has a small stock of these in various lengths, both with and without washers. They are available at very low prices on the CLEARANCE PAGE of this website. Click below to access the Clearance page.     CLICK HERE

For all tek screws. Whilst 19mm is our standard stock sizes fitted to the above screws, 16mm & 29 mm washers can be ordered as separate washers or fitted to most of the above screws. The 29mm washer is particularly useful for fixing rooflights in exposed areas. 

 Available in 5/16" (8mm) hexagon head to suit 16mm, 19mm, & 29mm washers. Stock items are the 12 BS standard colours in 5/16 (8mm) head with 19mm washer.   Other BS. and RAL colours are available to order. Please specify BS. or Ral. number. CLICK HERE to see 12 BS colours

    To fit any electric drill. Both 3/8 and 5/16 heads available. Drill MUST have a speed & a torque control for both correct tightness and safety (To avoid sprained or broken  wrists) A Tek Gun (electric drill) can be hired from any good tool hire firm.

THE COWBOY'S  WAY OF FIXING TEKS.

With the Type AB Tek for wood, some people use them as nails, driving the Tek home with a hammer.

This method risks the tek screw not being at a right angle to the sheet and thus not sealing. Using the thicker 0.55 and 0.7 mm thick sheets there are risks of the screws forming depressions in the sheets were the washers will sit before penetrating the sheet and thus not producing a watertight seal or a waterlogged seal.

Only consider using a hammer were a watertight seal is not needed. If you have to use teks as a nails on say a small emergency repair, see that the tek is at a right angle to the surface and  finish tightening the teks with a socket on a ratchet spanner to the correct tension.

Properly inserted Teks don't leak.