This article is considered accurate for the current version (1.56) of the game.
A Bunker is a player-built structure partly-dug into the ground with a Shovel. It can be upgraded for more Health and better Resistance and transformed with various Modifications. It can be connected to other Bunkers and Trenches.
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An underground shelter that serve as foundation for permanent fortifications. Connects to other Bunker and Trenches.
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— In-game description
Construction
A Tier 1 Bunker is built with a Shovel. It can be connected to other Bunkers by their sides and to Trenches by their ends or their center (hold Shift to deactivate auto-snapping). It can't be built on Beaches, paved areas, ice, roads, or steep slopes.
If you directly join two bunkers together, the wall between them disappears and the two sections become one single bunker complex with shared health. If one of the parts gets destroyed, they all get destroyed.
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An underground shelter that serve as foundation for permanent fortifications. Connects to other Bunker and Trenches.
„
— In-game description
Construction
A Tier 2 Bunker is built by upgrading a Tier 1 Bunker with a Hammer and 75 Basic Materials.
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An underground shelter that serve as foundation for permanent fortifications. Connects to other Bunker and Trenches.
„
— In-game description
Construction
A Tier 3 Bunker is built by upgrading a Tier 2 Bunker with a Hammer and 15 Concrete Materials. However it needs to be connected (by trench or bunker) to a Bunker Base with the Concrete Structures upgrade. The Concrete Materials used takes 24 hours to dry, during which the Bunker is more vulnerable.
Structural Integrity
A Bunker complex with 3 pieces: a Tier 2 AT Gun Garrison, a Tier 2 Bunker, and a Tier 2 Rifle Garrison.
A large bunker complex can be built by joining together multiple bunkers, pooling together their health. However a complex with more bunkers has a lower Structural Integrity. The health of a bunker complex is equal to the sum of the health of each bunker piece multiplied by its Structural Integrity. With a Hammer in "Upgrade Mode" (F), you can see a bunker complex's approximate Structural Integrity in text: High(0.75-1), Medium(0.5-0.75), Low(0.25-0.5), Critical(0-0.25).
Each bunker piece inside the complex has a multiplier that affects the Structural Integrity. It depends on the piece's tier and nature (Structure Upgrade installed):
A bunker complex's Structural Integrity is equal to the product of the multiplier of each individual bunker pieces that compose it.
When modifying a bunker, each upgrade's description mention a "Structural Integrity Rating" to indicate their relative impact on the Structural Integrity of the bunker complex. "High - High" means a relatively low impact whereas "High - Low" means a very significant decrease in structural integrity.
Bunker Complexes should never reach "Critical integrity" as their health and repair cost would greatly suffer. Reaching "Low" is not advised, adding more pieces past "Low" integrity never give more health to the complex.
As a rule of thumb, a Tier 1 bunker complex should have 4 or fewer pieces and never more than 7. A Tier 2 complex should have 12 or fewer pieces and never more than 20. Tier 3 complexes are such that the number of pieces is virtually not an issue.
Modifications
Modifications can be added to a Bunker with a Hammer in "Upgrade" mode (switch with F), press E to open the upgrade menu.
Small Modifications
Adding a Small Modification makes your character perform a short construction animation after which the modification appears. The materials will automatically be taken from your inventory. Use Mouse Wheel to select the orientation and position of the Small Modification when relevant. They can be removed by pressing Right Click on their icon option in the upgrade menu instead of Left Click.
Name
Icon
Description
Cost
Removal Cost
Doorway
Provides entry into this Bunker.
20
10
Firing Port
Allows infantry weapons to be fired from the safety of this bunker. However heavy weapons (Machine Guns, etc...) can't be rested on the firing port ledge.
20
10
Pipes
Provides power connections from Engine Rooms to Storm Cannons and other powered bunker pieces, such as garrisons.
30
15
Interior Firing Port
Provides cover against enemies that have entered this Bunker. Tier 3 only.
10
5
Stairs
Allows easy access to the roof of this bunker. Only Tier 2 and 3.
30
15
Ladder
Permits access into this Bunker from the roof. Only Tier 2 and 3.
20
10
Sandbags
Bunker Sandbags gives a secure firing position on the roof while preventing enemies from climbing onto your bunker.
1
20
Infrastructure Modifications
An Infrastructure Modification can be installed inside a Bunker if it's connected to a Bunker Base. Each cost 50 and give different bonuses to the connected bunkers depending on their Infrastructure Type. Removing them cost is 25 . They contribute to the Infrastructure requirement to unlock the Base Upgrades at all the connected Bunker Base nearby.
Some infrastructure modifications only become available after a certain amount of infrastructure modifications of the same infrastructure type have already been built.
The Infrastructure bonuses are no longer applied to a particular bunker if its trench/bunker connection is severed.
Garrison Infrastructures
They are needed to unlock Infantry Garrisons (4), AT Gun Garrison (12), and Howitzer Garrison (24).
+1% chance for a soldier not to consume Soldier Supplies upon respawning (max 10%)
None
Latrine
+1% chance for a soldier not to consume Soldier Supplies upon respawning (max 10%)
5
Wash Station
+3.33% fire rate to AT Gun Garrisons and Howitzer Garrisons (max 66.6%)
10
Kitchen
+3.33% fire rate to AT Gun Garrisons and Howitzer Garrisons (max 66.6%)
15
Pantry
+3.33% fire rate to AT Gun Garrisons and Howitzer Garrisons (max 66.6%)
15
Command Infrastructures
They are needed to unlock Observation Bunkers (6), Concrete Structures (12), Deployment Point (24), and Advanced Bunkers (40).
Name
Icon
Bonus Type
Required Modifications
Workstation
-1% power cost of Storm Cannons or Intelligence centers ( max 20%)
None
Computer Module
-1% power cost of Storm Cannons or Intelligence centers ( max 20%)
None
Radio Station
+1% range to Observation bunkers (max 20%)
10
Chalk Board
+1% range to Observation bunkers (max 20%) (Not shown on the intel circle size on the map)
10
Strategic Map
+1% range to Observation bunkers (max 20%) (Not shown on the intel circle size on the map)
15
Structure Upgrades
A Bunker can be modified into various specialised structures. Only one Structure Upgrade can be installed and it cannot be removed once built. It deletes all Small Modifications and Infrastructure Modifications that are in conflict with it (e.g. sandbags & ladder add-ons removed when placing a bunker garrison, or infrastructure modification removed when placing an engine room).
Most Structure Upgrades require that the Bunker is connected (by trench or bunker) to a Bunker Base with certain base upgrades unlocked.
A radio bunker that provides intel to friendly units about the surrounding area. Reinforced with wood, it can withstand more punishment than a standard radio tower, and therefore is capable of increased effectiveness.
Observation Bunkers
Only on Tier 2 and Tier 3 bunkers.
Cannot be adjacent to another garrison Upgrade, even diagonally.
A high-tech listening post designed to intercept and decode enemy transmissions. The intelligence Center can target distant locations and will continue to decipher sensitive transmissions over a sustained period.
Advanced Bunkers
Only on Tier 3 bunkers.
Cannot be adjacent to another garrison Upgrade, even diagonally.
Requires a 3 by 3 bunker complex.
Bunker Husk
When a bunker is destroyed, it leaves behind a husk. The bunker can be rebuilt from the husk by using the hammer in upgrade mode and pressing E. This will replace the husk with a bunker blueprint at the tier it used to have, for the cost of that tier (e.g. shoveling for Tier 1, Hammer and 75 bmats for Tier 2). If the bunker had a Structure Upgrade modification (Rifle Garrison, Bunker Corner, etc...) then rebuilding it won't restore any of the previously installed modifications, they'll have to be reinstalled at normal cost after bunker reconstruction. However if the bunker had no Structure Upgrade modification then all small modifications and infrastructure modifications are restored when the bunker is rebuilt.
Unlike trench husks, bunker husks cannot be filled in with a shovel.
The husk can be destroyed with explosives, to make space for different structures for example. The bunker husk has the same max health as the bunker it comes from. Or you can wait for decay to destroy it. Husk decay cannot be prevented and is usually the same speed as the decay near region borders.
A Bunker husk still spreads Bunker Base upgrades to connected trenches and bunkers.
Interactions
Interactions are available in the bunker's upgrade menu:
The original builder can instantly demolish it if it was built less than 3 hours ago (initial materials refunded but not the upgrade costs).
The bunker can be reserved for a Squad to prevent non-members from modifying it (however the stockpile access is not restricted).
The list of all special actions done to the bunker can be viewed with the "View Action Logs" button .
Tips
Upgrading T1 Rifle Garrison to T2, T3 Rifle Garrison is cheaper than build T2, T3 bunker first and upgrading to Rifle Garrison. Upgrading T1 Rifle Garrison to T2 costs 75 Basic Materials and T2 Rifle Garrison to T3 costs 30 Concrete Materials like normal bunker does.
You can hold shift while placing bunker blueprints to prevent them from automatically connecting to another bunker or trench.
"Nearby" on Infrastructure Modifications refers to trench/bunker distance not linear distance, this being within 40 unit pieces of the infrastructure modification.
When a bunker is destroyed every infantry in it dies. Even vehicles that touch the bunker might be instantly destroyed.
Infrastructure Modifications can be placed on bunker pieces who already have a bunker garrison upgrade (Rifle Garrison, etc).
Gallery
Howitzer Garrison
Bunker Blueprint, Shovel required to build
Storm Cannon
Engine Room
Various upgrades: (in order) Tier 1 Garrison, Tier 2 Machinegun, Tier 3 AT, Engine room; Firing Ports, Doorway, Trenches with Barbed Wire, a Trench Bridge, and Pipes
Engine room adversely affects integrity
Trench's length is equal to two connected bunker's length
Tier 1 Trench and Bunker husks
Bunker upgrade descriptions list Structural Integrity Rating, construction requirements, power consumption, and building cost
A Tier 3 Bunker with Ladder and Stairs add-ons
A Tier 2 Bunker with Ladder, Stairs, and Sandbags add-ons
A Bunker complex with 3 pieces: a Tier 2 AT Gun Garrison, a Tier 2 Bunker, and a Tier 2 Rifle Garrison.
