Wood Movement Explained: Why Boards Expand and Contract

Why Wood Moves

Wood absorbs and releases moisture. Expansion and contraction follow humidity. Movement occurs across grain primarily. Along-grain movement minimal.

Planning for Movement

Allow expansion in panel designs. Use slots for tabletop attachment. Breadboard ends require special joinery. Cross-grain construction fails.

Seasonal Changes

Wood wider in humid summer. Contracts in dry winter. Finish slows but does not prevent movement. Climate control reduces extremes.

Design Solutions

Frame and panel accommodates movement. Floating panels in grooves standard. Elongated holes allow fastener movement. Proper design prevents cracking.