The "Gold Standard" for Screw Selection
Based on our guidelines, we recommend the following types of screws:
Material: 304 or 316 stainless steel
304 Stainless Steel: explains that this option is the most versatile. Stainless steel has chromium and nickel. these elements form a protective layer which makes the stanless steel more resistant to corrosion. 304 stainless steel works for most areas that are away from the coasts and high salinity sites.
316 stainless steel: The 316 stainless steel alloy is best for near-ocean or salt applications. The alloy has molybdenum which enhances the corrosion resistance of alloys to chlorides. A 316 alloy is a solid long-term investment.
Avoid: Do not use anodized, common steel or aluminum screws because the galvanized coating may rapidly deteriorate in the alkaline setting of cement fiberboard and rust. Also, aluminum screws may be soft and corrode easily.
Threads: Fine-tooth, high-thread design
Fiber cement board is dense and brittle. Standard wood screws with large threads can cause stress and cracking. Instead, use fine-tooth, high-thread screws made for fiber cement. This design offers:
Low cutting resistance: It allows for easy entry, reducing edge chipping.
Large engagement area: Dense threads create a stronger grip, reducing loosening.
Stress dispersion: It eases expansion pressure during tightening.
Drill Bits: The self-drilling function is crucial.
Choose screws with built-in hard tungsten carbide drill bits. These penetrate fiber cement with ease without pre-drilling. This improves efficiency and keeps screws aligned. Pre-drilling can take time and may cause large holes, affecting stability.
Screw head: trumpet head or flat head with a washer.
Trumpet head: This common choice has a tapered design that sinks into the board for a clean look.
Flat head with washer: Regardless of the type, a rigid washer is essential. It serves two key purposes:
Distributing pressure: It spreads the screw's force in an even manner. This helps prevent damage to the board edges.
It fits tightly against the board. This creates a waterproof barrier that prevents moisture from entering the screw hole.
Key Installation Precautions
Choosing the right screw is vital, but proper installation is key.
Keep a vertical orientation: Always push screws directly into the board. Do not insert screws at an angle-doing so, may weaken the grip and destroy the hole.
Tighten screw lightly: Tighten the screw until the washer is flat against the board. Over-tightening the screw can crush the board and break the waterproof seal.
Allow for thermal expansion and contraction: Boards will expand and contract with temperature. Always leave a gap between boards and fixed edges as instructed in our installation directions.