10Gx40 Modwood Metal Decking Screw 410SS

What is the 10Gx40 Modwood Metal Decking Screw designed for?
These screws are specifically designed for attaching Modwood decking to steel and aluminium substructures. They're suitable for grooved and solid boards, steps, screening and fascia applications.

Do I need to pre-drill the metal substructure before installing Modwood metal deck screws?
No — the #3 drill point is designed to bore through steel and aluminium framing up to 4mm without pre-drilling the substructure. However, if you're installing Modwood Xtreme Guard decking, you must pre-drill the board itself using a 4.8mm drill bit before driving the screw.

What steel gauges are these screws compatible with?
Modwood 410SS screws are designed for steel gauges 18 through 12, as well as two doubled-up 14 gauge joists — covering the most common steel substructure configurations used in residential and commercial decking builds.

How do I know the screw has engaged properly in the metal frame?
The screw should not move at all if the screw has properly sheared through the metal joist. If the screw lifts or moves, then it hasnt engaged the joist properly.

What do the wings on the screw actually do?
The wings sit just below the screw thead and serve two purposes. They increase the speed and effectiveness of the drill point as it penetrates the metal, and they prevent mushrooming of the board surface during installation. Once the screw clears the metal framing, the wings shear off cleanly so the screw can seat flush.

How do I get a consistent flush finish on the screw head?
The Modwood Deck Screw Depth Setter is the easiest way to achieve a consistent flush finish across the whole deck. It removes the guesswork from seating depth and helps avoid over or under-driving, which is particularly important on composite decking where surface damage can't be sanded back.

Are these screws suitable for coastal or poolside installations?
The 410SS grade offers good general corrosion resistance thanks to its design, but for installations exposed to salt air, near large bodies of salt water or around swimming pools, grade 316 stainless steel fasteners are recommended for a higher level of protection.

What's the difference between the 410SS metal screw and the 305SS or 316SS timber screws?
The key difference is the tip design and intended substructure installation. The 410SS is engineered to penetrate metal framing, while the 305SS and 316SS are designed for timber substructures. Using the wrong screw for your substructure type will affect both installation performance and long-term holding power.

Can I use these screws with any Modwood decking product?
These screws are suitable for attaching any 23mm thick Modwood decking boards to steel and aluminium substructures generally, but if you're installing Modwood Xtreme Guard specifically, pre-drilling the board with a 4.8mm bit is mandatory before driving the screw.