Proper spacing between deck boards is essential for structural integrity and longevity. Typically, a gap of 1/8″ to 3/16″ is recommended for pressure-treated lumber to allow for expansion and contraction due to moisture. Wider gaps, up to 1/4″, may be suitable for composite or other materials less prone to swelling. This space accommodates seasonal changes and prevents the deck from buckling or warping.
Correct spacing facilitates proper drainage, preventing water accumulation that can lead to rot, mildew, and premature deterioration. Historically, gaps were often determined based on the natural shrinking and swelling properties of green lumber. Modern practices, using kiln-dried and treated lumber, require more precise spacing guidelines for optimal performance and aesthetic appeal.