The gap between deck boards isn't just for looks—it allows water to drain and debris to fall through. Without it, your deck will rot faster than you can say "barbecue."
The 1/8 Inch Rule (Usually)
The standard gap is **1/8 inch**. This is roughly the width of a 16d nail (a common spacer tool). However, wood moves.
- Wet Pressure-Treated Wood: Install it TIGHT. As it dries in the sun, it will shrink, creating a perfect 1/8 to 1/4 inch gap naturally.
- Kiln-Dried / Composite: Install with the EXACT gap (usually 1/4 inch). It won't shrink much.
Screws: Stainless vs Coated
Modern pressure-treated lumber (ACQ) is full of copper, which eats aluminum and standard steel.
- Polymer Coated (Green/Tan): Good standard choice. Cheap and effective.
- Stainless Steel (305 or 316): Expensive but mandatory if you live near the ocean (salt air).
Hidden Fasteners?
Camo systems or clip systems look great but are harder to replace if a board rots. Face-screwing is traditional and easiest to maintain.