Hearts of Iron IV – Construction & Buildings

Throughout Hearts of Iron IV, the player is bound to construct something at some point. Whether its repairing vital infrastructure or expanding your production capacity, construction is a vital mechanic to utilize throughout your campaigns.

What is Construction?

Construction is a mechanic in Hearts of Iron IV that is responsible for the building and repairing of buildings within your states and provinces. It is driven by the number of civilian factories in your country, as these determine how fast construction occurs. A maximum of 15 civilian factories can be assigned to a construction project at once, with any excess factories being free to assign to other projects.

Provincial Buildings

Within each state are a number of provinces in Hearts of Iron IV. While most buildings are constructed at a state level, some are constructed within individual provinces.

Railways and Supply Hubs

Introduced in No Step Back, railways and supply hubs are vital for maintaining an efficient supply network. Supply hubs function as depots, supplying nearby divisions and moving supply to the next stop in your network if no divisions are nearby. Railways are cheap to build and distribute supply to hubs around your country. It’s important to make sure you have a steady supply of trains, otherwise railways won’t function.

Additionally, bottlenecking is a concern for both railways and supply hubs. Your supply network is only as strong as the weakest link, so if you have a series of level 3 railways with one level 1 railway between two hubs, only the lowest amount of supply will be provided

Fortifications

Forts are excellent for shoring up the defenses on your borders or preparing fallback lines if you are being invaded. Two types of forts exist in the game, land forts and coastal forts. They each provide a 15 percent combat bonus for each level of fort in a province, with a maximum level of 10. These are invaluable if you are a minor power near a major, or if you share a tiny border with a potential enemy.

Naval Bases

The other type of provincial buildings are naval bases. These bases increase the supply to an area and house your fleets when they are not on missions. Building these should be a priority if you plan to rapidly expand your fleet. They should also be built when you are doing an extensive naval invasion, such as one of North America. Without a high level naval base, it is possible your troops run out of supplies and your invasion gets stalled.

State Buildings

These buildings provide benefits throughout an entire state instead of the single province. State buildings can provide bonuses related to both projecting power and defending your land.

Air Base

Without air bases, you might as well not have an air force. Each level of air base provides an additional 200 capacity for planes, and these also extend where you can deploy your air force. Bases placed close to an enemy border can be risky, but they will let your planes fly further into their territory.

Anti-Air

If somebody has multiple air bases near your border, you should consider investing into some anti-air guns. These will damage any enemy planes flying over the state and reduce the effectiveness of bombing runs.

Radar Station

Radar stations are invaluable for collecting intelligence. With them you can expect more knowledge of enemy land forces, better effectiveness at countering aerial attacks, and increased knowledge of any enemy ships at sea.

Infrastructure

Both in Hearts of Iron IV and real life, infrastructure is the backbone of any country. High level infrastructure increases the supply available to nearby units and improves their movement speed in the entire state. In addition to those benefits, it will increase the building speed of our next category, shared buildings.

Shared Buildings

The most impactful buildings in the game have to be shared buildings. These include your production buildings, oil storage, and missile silos. Shared buildings get their names due to them sharing the same building slots in a state. For example, if a state has a maximum of 8 buildings, then you can have a total of 8 of the buildings below.

Production

Production buildings are responsible for construction, creating weapons, and building ships for your navy. These include civilian factories, military factories, and naval dockyards. They all have a maximum level of 20, but you realistically will have a hard time getting close to that with the building limits of states.

Civilian factories are unique as production buildings because they are responsible for building the other production buildings. In addition to this, they are used for intelligence agencies and trading. Thanks to the extensive uses of civilian factories, you should prioritize building these before other buildings in a state.

Oil Buildings

This category includes your synthetic refineries and your fuel silos. Synthetic refineries produce fuel and rubber, which are very valuable for waging war. Refineries are critical to use if you don’t have easy access to natural oil. They can also be very helpful if your having fuel problems from having a large navy or air force. Fuel silos store the fuel, with each one increasing your countries maximum fuel storage capacity. Location does not matter with either of these, as the benefits are felt throughout your entire country.

Rocket Sites and Nuclear Bombs

Towards the end of the game, players unlock the ability to build both guided missiles and nuclear bombs. Rocket sites will produce one rocket per day, while nuclear reactors will slowly create nuclear bombs. Due to how late in the game these are unlocked, they usually have limited use, especially for experienced players.

Rockets function as planes, so they have limited range and building sites on the border of potential enemies is crucial. You will need multiple nuclear reactors to efficiently construct bombs, as well as a powerful air force to escort them to their target.

Overview

To successfully dominate in Hearts of Iron IV, utilizing every building type will be essential. Knowledge of buildings will help when you have inactive civilian factories, and when you are prioritizing targets in your next invasion.