NONOX decking screw (DIN 7505 type A countersunk head Torx decking screw)

Nowadays wooden decking is fashionable. This is no accident. Wood decking is natural, it radiates warmth, while at the same time being hard-wearing and decorative, and it is ideal for surfacing the walking area around a pool, or garden paths. In my article I do not wish to cover all the phases of decking, only to focus on the screwing of the boards. Many people make the mistake of not paying sufficient attention to the use of the appropriate decking screw. It is a fact that the boards can also be fixed to the joist with simple wood screws, but if you want a perfect and, above all, long-term solution, then use screws developed expressly for decking. This is especially recommended in the case of hardwood decking.

How does the NONOX decking screw differ from a traditional wood screw?

1. Outdoors, decking screws are exposed to the vagaries of the weather. I imagine it needs no explanation if I say use only a screw that is stainless in its material, of austenitic A2 grade. Zinc-coated screws may be damaged during driving, and at the site of this damage rust spots appear within a year or two. And rust is not worthy of a deck made of quality wood. The NONOX decking screw featured in the article is made of hardened, martensitic stainless steel, which has been reinforced under the head section, and the thread has been provided with a coating that eases driving.
2. The point of decking screws is made with a cutting edge, which cuts the wood in continuous ribbons. This makes driving without pre-drilling possible, with which a great deal of working time can be saved.
3. Thanks to the wavy thread design of the decking screw, it grips so strongly in the joist that the joint can essentially be regarded as self-locking.
4. Above the thread there is a hole-enlarging rib, which removes the thread from the board, so the thread holds only in the joist, not in the board. Thanks to this the screw head draws the board tightly to the joist, so the gap between the two is in principle eliminated.
5. The smaller head diameter and the self-countersinking cutting edges under the head make perfect countersinking possible, and because of this a further operation, pre-countersinking, can be saved.
6. A Torx drive helps us to transfer the torque from the tool to the screw as securely as possible.

How many screws will be needed for the deck?

The thickness of the boards determines the joist density. In the case of 21 mm thick board, support is needed every 50 centimetres. In the case of thicker, e.g. 28 millimetre boarding, joists every 70 centimetres are already sufficient. Every board must be fixed with two screws at every support point.

The screwing procedure

Place the boards at least 5 mm apart from one another! To keep the joint spacing even, use a tile spacer, or small pieces of wood! For marking out the position of the screws it is worth making a template. Fix the boards first at the two end points! After this there is still the opportunity to straighten any bent boards with a parquet clamp or a ratchet strap. After this, fix the boards at every connection point with two decking screws each! The minimum fixing depth is four times the diameter, but depending on the wood species it is optimal to reach eight times the diameter in fixing depth. It is advisable to carry out trial fixings!

Summary of the advantageous properties

1. Stainless (it does not rust);
2. Hardened (excellently suitable for hardwood too);
3. Reinforced head (the head does not break off);
4. Driving-easing coating (faster driving);
5. Self-tapping point (no need to pre-drill, it does not bind in the wood);
6. Wavy thread (it reduces the stress);
7. Hole-enlarging rib (it draws the layers together, and furthermore the resistance on driving is reduced by 30-40%);
8. Smaller head diameter (less head resistance);
9. Self-countersinking cutting edges under the head (another saved operation: no need to pre-countersink);
10. Torx drive (much better force transmission)

Sizes

ø	Total length	Thread length	TX	pcs / pack
5.0	40	26	25	100
	50	36	25	100
	60	40	25	100
	70	50	25	100
	80	50	25	100