Deck-Tite Plus A4 Countersunk Screw - 4.5 x 57mm - Silver

A4 stainless steel, also known as 316 grade, contains molybdenum, which significantly enhances its resistance to corrosion, particularly against chlorides and acids. This makes it superior to A2 (304) grade in marine and highly polluted environments.

The square drive (Robertson drive) is known for its excellent torque transmission and resistance to cam-out (the driver bit 'climbing' out of the screw head recess). This reduces the risk of damaging the screw recess and stripping the head, especially during high-torque applications with impact drivers.

TDCA DeckMark+ is an accreditation by the Timber Decking Association signifying that the product meets rigorous standards for quality, performance, and durability in decking applications.

Yes, these screws are suitable for use with treated timber, offering protection against the corrosive elements often found in treated wood preservatives.

The spiral point is a self-drilling feature that helps the screw to start easily and penetrate the material quickly without requiring a large pilot hole, reducing the effort needed for installation.

The unthreaded portion near the head allows the top piece of timber (e.g., the deck board) to be pulled down firmly against the lower piece (e.g., the joist) without the unthreaded shank pushing the top piece upwards, ensuring a tight and secure joint.

Ensure you are using the correct size and type of square drive bit. Reduce the torque setting on your impact driver if it is too high, or consider pre-drilling a pilot hole.

This is usually due to the thread pulling the timber too quickly. Ensure the part thread is engaging correctly with the joist. If the issue persists, a slightly larger pilot hole in the deck board might help, or ensure the timber is adequately clamped down.

Pre-drill a pilot hole that is slightly smaller than the screw's core diameter. Ensure your power tool has sufficient power and torque.

While A4 stainless steel is highly resistant, contamination during installation or exposure to extremely aggressive chemicals can cause superficial staining. Clean the affected area with a non-abrasive cleaner. If extensive corrosion occurs, the grade of stainless steel may not have been suitable for the specific micro-environment.