Construction
Constructions are fixed assets that may be built in states or provinces that are constructed using civilian factories.
State buildings[edit | edit source]
![]() |
This is a community maintained wiki. If you spot a mistake then you are welcome to fix it. |
These buildings are built on a state level. Control of state resources or buildings requires controlling provinces worth at least 50% of the VP of that state, even if that does not include the province where the building icon is located. Airbases will appear, but do not become usable, unless the player also controls the province containing the airbase.
Name | Cost | Maximum level | Effect | |
---|---|---|---|---|
![]() |
Infrastructure | 6000[1] | 5[1] | Increases supply and supply throughput. Increases the movement speed of land units. Affects the organization recovery rate of land units. Resources output is increased by +20%[2] per level. Increases construction speed of ![]() |
![]() |
Air base | 1250[1] | 10[1] | Bases and repairs air units. Each air base level can host 200[3] aircraft. |
![]() |
Anti-air | 2500[1] | 5[1] | Damages attacking air units and reduces damage from bombing. See state anti-air. |
![]() |
Radar station | 3375[1] | 6 (depends on technology)[1] | Detects enemy forces, especially incoming aircraft. Radars also help detect enemy ships at sea and can increase intelligence in other nations. |
[edit | edit source]
![]() |
This is a community maintained wiki. If you spot a mistake then you are welcome to fix it. |
Like state buildings, shared buildings are built on a state level; however, they share a limited number of slots. This is perhaps the most important category of constructions, since it contains the factories necessary for production. Refineries have a hard cap of up to 3 refineries per state.
Name | Base Cost | Maximum level | Effect | |
---|---|---|---|---|
![]() |
Civilian factory | 10800[1] | 20[1] | Produces consumer goods and constructions, or can be used for trade, or can be used to create and upgrade intelligence agencies. Base output is 5[4] (per day). |
![]() |
Military factory | 7200[1] | 20[1] | Produces equipment (includes weapons, planes, vehicles). Base output is 4.50[5] (per day). |
![]() |
Naval dockyard | 6400[1] | 20[1] | Produces and repairs ships. Base output is 2.5[6] (per day). |
![]() |
Synthetic refinery | 14500[1] | 3[1] | Produces 48-168 fuel and ![]() |
![]() |
Fuel silo | 5000[1] | 3[7] | Stores fuel (+100 000 per silo)[1]. |
![]() |
Rocket site | 6400[1] | 2[8] | Produces (and can launch) one rocket per day per site. Max storage capacity is 100[9] rockets per rocket site level. Therefore a level 2 rocket site has a maximum capacity of 200 rockets. Rockets are also known as guided missiles. |
![]() |
Nuclear reactor | 30000[1] | 1[1] | Produces nuclear bombs at a rate of 1[10] per year (365 days). |
Infrastructure effects[edit | edit source]
Construction speed of all buildings depends on the level of infrastructure in the state. Construction speed is multiplied by
Where the INFRA_MAX_CONSTRUCTION_COST_EFFECT in /Hearts of Iron IV/common/defines/00_defines.lua defaults to 1, and Maximum Infrastructure Level defaults to 5 in /Hearts of Iron IV/common/buildings/00_buildings.txt.
So for example ×1.6 at 3/5 infrastructure. In the Construction UI, this bonus is displayed for each State as a colored percentage next to an Infrastructure road icon. This bonus is applied after bonuses from tech, advisors, and national spirits, making 1 level of infrastructure a more powerful bonus than e.g. a War Industrialist. This encourages players to concentrate industry in central, high-infrastructure areas, although this must be balanced against the increased vulnerability of having all of one's industry in one place.
Given the above formula and values and the lost production points from forgone civilian factories during the time of infrastructure production (uncompounded opportunity cost), the following table shows the minimum number of open slots for civilian factories to break even on the increased cost of infrastructure. One might infer that it is rarely advantageous to add more than two levels of infrastructure for construction speed alone.
End | Start at 0 | Start at 1 | Start at 2 | Start at 3 | Start at 4 |
---|---|---|---|---|---|
1 | 4 | ||||
2 | 7 | 4 | |||
3 | 12 | 8 | 5 | ||
4 | 16 | 13 | 9 | 5 | |
5 | 22 | 18 | 15 | 10 | 6 |
Note that the returns don't diminish as much as one might expect because of reduced opportunity cost (days of lost infrastructure production from fractional factories) when moving from higher versus lower starting infrastructure and producing civilian factories. Returns for construction other than civilian factories diminish faster because other infrastructure does not return production points and, thus, has no opportunity cost beyond the break-even level. For example, a close approximation of the break-even number of open slots for military factories is the number in the table * (1.125 + (0.05 * end_infrastructure_level)).
The total amount of resources can also be increased by building infrastructure. Each level of infrastructure gives a resource increase of +20%[11] to the total of all extracted resources (except those resources produced by a synthetic refinery or resources acquired via trade) in a state. There are five (5) levels of infrastructure; building all of them will give a +100% bonus to the extracted resources total.
The infrastructure level also affects land unit organization recovery rates per the following table:
Infrastructure level | 5 | 4 | 3 | 2 | 1 |
---|---|---|---|---|---|
Organization recovery rate | +25% | +15% | +5% | -5% | -15% |
Once a state's Infrastructure reaches maximum (level 5), a building slot can be added to that state using a Decision called “Region-wide Industrial Integration” that costs 100 PP.
Diminishing Returns[edit | edit source]
Infrastructure provides diminishing returns to build times.
Note: this is now out of date for the current version which has 5 levels of Infrastructure instead of 10.
Changing a province's infrastructure from 0 to 1 would require 5 military factories or 3 civilian factories to break even, 1 to 2 is 6 military or 4 civilian, all the way up to 9 to 10 which requires 16 military or 11 civilian.
It is generally not economical to build more infrastructure solely for the purpose of increasing construction speed. Infrastructure is a relatively better deal in states with many empty slots; when planning to build civilian factories, refineries or reactors as they cost more; and at the start with countries with bad economy laws like the USA, as infrastructure construction isn't penalized like factory construction is.
Reconstructing[edit | edit source]
It is possible to deconstruct shared buildings from the state tab by hovering over the building icon and pressing the X that appears in the lower right corner of the icon. During wartime, each state can only deconstruct one building per 30[12] days.
Slot count[edit | edit source]
Each state has a category, which then decides the base number of shared slots. Various technologies give percentage bonuses to how many slots a state can have. Various National Focuses may give additional bonus slots. The total number of slots is capped at 25[13].
Category | Default number of slots[14] | Name in source files | Example State |
---|---|---|---|
Megalopolis Region | 12 | megalopolis | Greater London Area |
Metropolis Region | 10 | metropolis | New England |
Dense Urban Region | 8 | large_city | Southern Ontario |
Urban Region | 6 | city | Svealand |
Sparse Urban Region | 5 | large_town | Nebraska |
Developed Rural Region | 4 | town | Sardinia |
Rural Region | 2 | rural | Madagascar |
Pastoral Region | 1 | pastoral | Hejaz |
Small Island | 1 | small_island | Iwo Jima |
Enclave | 0 | enclave | Gibraltar |
Tiny Island | 0 | tiny_island | Midway Island |
Wasteland | 0 | wasteland | Libyan Desert |
Province buildings[edit | edit source]
![]() |
This is a community maintained wiki. If you spot a mistake then you are welcome to fix it. |
These buildings are built on a province level. Unlike state or shared buildings, these buildings benefit whoever controls the province they are in regardless of overall control of the state.
Name | Cost | Maximum level | Effect | |
---|---|---|---|---|
![]() |
Naval base | 5000 + 1000 * current level[1] | 10[1] | Stations naval fleets, and can send and receive supplies and resources via convoys. Each naval base level increases supply capacity, supply throughput and the number of local ship repairs[15]. |
![]() |
Land fort | 500 + 500 * current level[1] | 10[1] | Inflicts an attack penalty of -15%[16] for each fort level on the attacker in combat. Attacking from multiple directions will reduce forts effect. |
![]() |
Coastal fort | 500 + 500 * current level[1] | 10[1] | Inflicts an attack penalty of -15%[16] for each fort level on the attacker in naval invasion and 'strait crossing' combat. |
![]() |
Railway | 170 + 130 * current level[1] | 5[17] | Transports supplies from the capital to supply sources like cities, ports or supply hubs. |
![]() |
Supply hub | 20000[1] | 1[1] | Distributes supplies from railways. |
Civilian factories[edit | edit source]
![]() |
This is a community maintained wiki. If you spot a mistake then you are welcome to fix it. |
Civilian factories make all the improvements to a territory and are necessary to build any of the constructions listed under the Construction tab . All nations start with a certain number of civilian factories and a percentage will be used for consumer goods, depending on the economy law and national spirits that are currently in place.
Civilian factories that are not used to produce consumer goods can be used for trade or to complete or repair the construction queued in the Construction tab. It's possible to increase the number of civilian factories by building more, but this is limited by the number of shared buildings slots available in each state
Consumer goods[edit | edit source]
Depending on economic laws, national spirits and stability, a number of civilian factories will be occupied by producing consumer goods and are unavailable for construction or trade. This number is computed as a percentage of the total number of factories, including military factories and factories received by trade. Factories are counted even when they are damaged and can't produce anything. The number of consumer goods factories is always rounded down.
![]() |
Universal | Country-specific |
---|---|---|
−20% | ![]() ![]() | |
−15% |
| |
−10% |
| |
−9% | ![]() | |
−8% |
| |
−7% | ||
−6% |
| |
−5% | Having 100% stability
(−1% from each 10% of stability over 50%) |
|
−4% | ![]() | |
−3% |
| |
−2% |
| |
−1% |
| |
+2% |
| |
+3% |
| |
+4% |
| |
+5% |
| |
+8% |
| |
+10% | ![]() |
|
+15% |
| |
+17.5 | ![]() | |
+20% | ![]() |
|
+25% | ![]() |
|
+30% | ![]() |
![]() ![]() |
+35% | ![]() |
![]() ![]() |
+50% | ![]() ![]() |
South Africa can gain -3% consumer goods at
Total Mobilization with its spirits, but will not gain additional factories by this.
- Example
Suppose the civilian economy law is enabled (requiring 30% of civilian and military factories dedicated to consumer goods) and no other modifiers apply. A country has 50 military factories, 50 civilian ones and 20 Dockyards. It will then have 30 (civilian) factories dedicated to consumer goods.
Output[edit | edit source]
The Factory Output of each civilian factory employed in construction is 5[4] per day. Construction Speed modifies the output for the building of all constructions.
![]() |
Universal | Country Specific |
---|---|---|
+15% | ![]() |
|
+10% |
| |
+5% | ![]() |
|
−10% | ![]() |
|
−30% | ![]() |
|
−40% | ![]() |
There are also modifiers which only affect a single type of building. These are, primarily, the political advisors (Captain of Industry, Fortification Engineer, Quartermaster General and War Industrialist) but can also be one of many other national spirits activated by national focuses or events.
Efficiency of additional Civilian Factories[edit | edit source]
The return on investment of building an additional Civilian Factory will depend on the Construction Speed bonus as well the Economy Law currently in place, or expected in the future. The higher the Construction Speed bonus is, the more Output will be done by the newly built Civilian Factory and the faster it will accumulate an Output equal to its cost, 10800. This variable is the time, in days, required to recover the cost of building the factory, or payback time.
The Economy Law will dictate what ratio of Civilian Factories are used for Consumer Goods and Output/Trade. The higher this ratio is, the longer the payback time of the newly built Civilian Factory will be. The payback time of a new Civilian Factory is given by the following formula:
The construction speed modifiers range between -70% and +65% and except for the lowest two modifiers, they all have multiple combinations to be achieved. In fact, there are 320 possible combinations of variables affecting Civilian Factory construction speed outside of national spirits and unique laws.
Economy Law | Construction Speed | |||
---|---|---|---|---|
Minimum (-70%) | 0% | Maximum (+65%) | ||
Payback Time
(Days) |
Undisturbed Isolation | 8000 | 2400 | 2087 |
Isolation | 5539 | 2216 | 1773 | |
Civilian Economy | 4115 | 2058 | 1524 | |
Early Mobilization | 2743 | 1920 | 1239 | |
Partial Mobilization | 2250 | 1800 | 1091 | |
War Economy | 2218 | 1695 | 1027 | |
Total Mobilization | 2000 | 1600 | 970 |
Minimal Construction Speed is -70% for Undisturbed Isolation and goes up to -20% with Partial Mobilization. Maximum Speed is 15% for Undisturbed Isolation and 65% with Partial Mobilization. All Values are rounded up to full days.
Additionally, because it's possible to assign up to 15 Civilian Factories (when available) to the construction of a new Civilian Factory, the number of days it will take to build a new one is given by the following formula:
Factory conversion[edit | edit source]
![]() |
This is a community maintained wiki. If you spot a mistake then you are welcome to fix it. |
Civilian Factories can be converted into Military Factories for 4000[1]. Military Factories can be converted into Civilian Factories for 9000[1]. The base cost is modified by several national spirits and political advisors. To convert a factory simply click on the corresponding state, and hover over the factory that shall be converted. The game will ask for confirmation. After confirmation the conversion now appears in the construction tab, just like any other building project.
Damage and repair[edit | edit source]
![]() |
This is a community maintained wiki. If you spot a mistake then you are welcome to fix it. |
Each building level has 100[18] HP. They may get damaged by port strikes (naval bases), land combat (infrastructure, forts), resistance (factories), strategic bombing, or explicit events (like the Soviet Union's decision to move factories to the Urals). Nuclear bombs can destroy multiple or all levels of a building at once, for details see nuclear bomb effects.
The damage from land combat (against infrastructure) and strategic bombing gets scaled by the building's damage factor (air base and radar: 0.5, anti-air: 0.1, 1 otherwise) and the squared ratio of the currently undamaged building levels to the maximum level. For example, a level-3 anti-air building (maximum level 5) where one level is already partially damaged only receives
of incoming damage from strategic bombing.A single military factory in a state (or in other words a level-1 military factory) receives
while 15 military factories receive . High-level factories and infrastructure will generally get damaged much more quickly from these two damage sources than lower levels.Anti-air provides damage resistance from bomber-type attacks (port strikes and strategic bombing) depending on the level of anti-air in the containing state and researched anti-air technologies. Dispersed Industry provides an alternative source of damage resistance but only for factories and not stacking with anti-air. The maximum of the two is used for factories.
All damaged buildings appear in the construction list. The speed of factories assigned to a repair line gets a bonus of +100% plus any Factory Repair Speed bonuses (e.g. from Construction technologies and Construction Repair continuous focus). Even when no factories are assigned, the speed of the line is 0.3[19].
The resulting daily repair progress is
, rounded to the nearest full percent. So when assigning no factories, repairs will still progress by 1% per day. Assigning just a few factories to repair an expensive building may also produce just 1% progress per day, effectively wasting the factory output.Politics | Ideology • Faction • National focus • Ideas • Government • Puppet • Diplomacy • World tension • Civil war • Occupation • Intelligence agency |
Production | Trade • Production • Construction • Equipment • Fuel |
Research and technology | Research • Infantry technology • Support Companies technology • Armor technology • Artillery technology • Land doctrine • Naval technology • Naval doctrine • Air technology • Air doctrine • Engineering technology • Industry technology |
Military and warfare | Warfare • Land units • Land warfare • Division designer • Tank design • Army planner • Command group • Commander • Battle plan • Combat tactics • Ship • Naval warfare • Aircraft • Air warfare • Experience • Officer corps • Attrition and accidents • Logistics • Manpower • Nuclear bomb |
Map | Map • Province • Terrain • Weather • State |
Events and Decisions | Events • Decisions |
- ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 1.12 1.13 1.14 1.15 1.16 1.17 1.18 1.19 1.20 1.21 1.22 1.23 1.24 1.25 1.26 1.27 1.28 1.29 1.30 1.31 from game file \Hearts of Iron IV\common\buildings\00_buildings.txt
- ↑ Defines NBuilding INFRASTRUCTURE_RESOURCE_BONUS = 0.2
- ↑ Defines NBuilding AIRBASE_CAPACITY_MULT = 200
- ↑ 4.0 4.1 Defines NProduction BASE_FACTORY_SPEED = 5
- ↑ Defines NProduction BASE_FACTORY_SPEED_MIL = 4.50
- ↑ Defines NProduction BASE_FACTORY_SPEED_NAV = 2.5
- ↑ from game file \Hearts of Iron IV\common\technologies\industry.txt
- ↑ from game file \Hearts of Iron IV\common\technologies\electronic_mechanical_engineering.txt
- ↑ Defines NBuilding ROCKETSITE_CAPACITY_MULT = 100
- ↑ Defines NCountry NUCLEAR_PRODUCTION_SCALE = 365
- ↑ Defines NBuilding INFRASTRUCTURE_RESOURCE_BONUS = 0.2
- ↑ Defines NBuilding DESTRUCTION_COOLDOWN_IN_WAR = 30
- ↑ Defines NBuilding MAX_SHARED_SLOTS = 25
- ↑ from files in folder \Hearts of Iron IV\common\state_category
- ↑ Local ship repair limitationsforum:1119095
- ↑ 16.0 16.1 Defines NMilitary BASE_FORT_PENALTY = -0.15
- ↑ Defines NSupply MAX_RAILWAY_LEVEL = 5
- ↑ confirmed by in-game testing using console command "building_health".
- ↑ This is not increased by the Construction Repair continuous focus forum:1251943