Building

Building is a gameplay mechanic in Fortnite and is a key component of Battle Royale, Save the World and some parts of Creative. It was introduced with the launch of Save the World, and has existed in every version of the game.

Basics
Building in Fortnite is achieved with four main structures: Walls, Floors, Stairs and Pyramids. Each of these structures can be edited to create new shapes. Each structure takes up a 1x1x1 place on the building grid, aside from walls which lie on the boundaries of each piece. The length of a tile is 5.12 meters. Each piece has several areas in which it can be edited to remove or raise elements of the structure. Doing so will rebuild it into the shape you have selected. There are a limited number of shapes for each piece, aside from the Pyramid which can function in any configuration.

Buildings must connect to the floor or a wall in some way, failure to do so will cause the structure to collapse, or it cannot be created at all. When a structure loses its connection to the floor, it will gradually collapse, destroying all 1x1x1 tiles surrounding it in quick succession, until each tile not connected to the floor is destroyed. There is no other mechanic aside from this relating to acceptable structures, as long as a single point connects to the floor or wall, the structure will remain.Each element of a build can be edited in several ways. Walls and Floors have a 3x3 grid which allows for the removal or inclusion of various shapes to create new structures. Stairs have a specific direction based grid to create thinner or angled staircases. Pyramids can have each corner raised in a 2x2 grid to make ramps and larger pyramids. Each structure can be created and swapped between using the specific binds. Console users are able to instantly build specific structures without a targeted placement, albeit less accurately.

Structures are made out of Wood, Stone or Metal. Each material has its own properties, with Wood being fast to build but weak, Metal being slow to build but strong, and Stone being a compromise between them. Structures are destroyed differently depending on game mode. Each structure costs 10 resources to build, and are free to edit. When weakened, these structures can be repaired for an amount relative to the damage they have taken as a percentage (If a structure is damaged 90%, it will take 9 resources to repair). Repairing takes a similar amount of time to building, but is quicker due to the structure already being placed and it needing to repair less HP than to build it.

In Save the World
Building in Save the World is used to create structures which stop husks from destroying Key Objectives in the Mission. Structures are also used to place traps, lead monsters down a specific path, or generally block enemies from attacking you. Most structures are not permanent, but those built in a Storm Shield Defense will remain indefinitely or until destroyed.

Upgrading
In Save the World, Structures can be upgraded, consuming more materials for each upgrade done. As such, Structures have three levels to them. The first level is the level at which they are constructed, having the least HP and taking the least time to build. The next level increases HP but increased build time. The third level repeats this at a larger increment. Each upgrade costs progressively more materials. A single structure costs 10 resources to create, the first upgrade costs 20 resources, and the third 30. This means a fully upgraded structure costs 60 resources. Upgraded structures can be repaired and destroyed the same as low tier ones. Adding XP points into the player's appropriate Skill nodes will allow the character to build better and stronger structures that have more health and will endure more damage before being destroyed.

Destroying
Structures can only be destroyed by the player, other players or by monsters. Players can only destroy structures with their harvesting tool, or by editing them in such a way they are no longer connected to the floor and are destroyed. Players cannot shoot or attack structures with anything but the harvesting tool. Monsters will progressively damage structures, with Mist Monsters dealing the highest damage. Certain traps or upgrades will decrease the monsters abilities to destroy structures, such as the B.A.S.E ability.

In Battle Royale
Building in Battle Royale is used to create structures which can aid you against other players, or protect you from enemy attacks. Unlike Save the World, structures can be attacked with weapons other than the Harvesting Tool and anyone can attack your structures regardless of team affiliation, with squad members only being able to use the aforementioned tool. Only squad members may edit your structures, or in the case of larger team modes like Team Rumble, teammates may edit them. You cannot place a Trap on an enemy structure. Structures in Battle Royale cannot be upgrade, but editing works the same way, as well as repairing.

Building in Battle Royale is much more fast paced and tactical, unlike Save the World. Whilst the latter requires patience and careful planning, the former does not rely on building bases or protecting an objective. In Battle Royale, building is a mobility tool, allowing for players to run across gaps by continuously building or gaining vertical height by continuously building stairs and floors. Building in Battle Royale is also used to protect you and your teammates, in order to allow for them to regain health, or revive a squad member. As such, building is much more tactical and harder to master than in Save the World, and has a much different general use.

In Classic Battle Royale modes (eg. Solo, Duo, Squads), the limit for all materials is 999 (297 pieces).

In Arena, the limit for all materials is 500 (150 pieces).

Trivia

 * Building to the height limit is known as a Sky Base.
 * Building a Stone Wall has a very small chance to add a Gnome in-between the bricks.