The most common building material in Fortnite is wood.
Fortnite Battle Royale lets players gather three standard construction materials: wood, stone or brick, and metal. Wood is generally the easiest and quickest material to collect because trees, fences, wooden buildings, and many other objects can be harvested across the island. That abundance makes it the material players most commonly have available, especially early in a match.
Wood is also the fastest material to build with, which makes it useful for emergency walls, ramps, edits, and quick protection during a fight. Its trade-off is durability: wood has the lowest starting strength of the main materials and is more vulnerable to damage than brick or metal. Newly placed wooden structures can therefore be destroyed quickly if an opponent focuses fire on them.
Stone or brick is stronger, while metal provides the greatest durability once fully built, but both take longer to gather or build effectively. “Most common” does not mean “best in every situation”; experienced players switch materials depending on available resources, incoming damage, and how long they expect a structure to survive.