A base without a lock is just a building anyone can walk into. Doors and locks are cheap, non-negotiable, and the first thing to get right before worrying about wall tiers.

Doors

There are three door types you will use regularly. Wood for early wipe when metal is scarce, sheet metal once you have a furnace running, armoured for TC rooms and high-value loot rooms later in the wipe.

Wood Door
Wood Door
200 wood
Fine at the start of a wipe when most players do not have the resources to raid. Vulnerable to satchels, beancans, shotgun shells, and fire. Replace with sheet metal as soon as the frags are available.
Sheet Metal Door
Sheet Metal Door
150 metal fragments
The standard door for most of the wipe. Significantly tougher than wood. Requires explosives to raid properly. Get both airlock doors to sheet metal before anything else.
Armoured Door
Armoured Door
5 gears + 20 HQM
The toughest door in the game. Expensive and overkill for most doors in the base. Worth it on the TC room and the innermost loot room once you have HQM to spare.
Double Door
Double Door
200 wood or 300 metal frags (sheet)
Two doors in a wider frame. Opens from the centre outward. Useful for garage entrances and vehicle bays. The wider gap when open is worth knowing about before placing on a main entrance.
Garage Door
Garage Door
300 metal fragments
Rolls up vertically instead of swinging. No gap when open. Commonly used as an outer layer on a main entrance or for vehicle storage. Requires a garage door frame rather than a standard door frame.

Door Health and Raid Cost

Doors are often the cheapest part of a base to raid. Two satchels will deal with a wood door. A sheet metal door takes more but is still cheaper than going through a stone wall. Knowing the rough raid cost of each door helps you decide where to spend on upgrades.

DoorHealthApproximate raid cost
Wood door2002 satchels / 1 rocket / fire / beancans / shotgun shells
Sheet metal door2504 satchels / 1 rocket / 1 C4
Garage door6009 satchels / 3 rockets / 2 C4
Armoured door80012 satchels / 3 rockets / 2 C4
Doors vs walls A stone wall costs significantly more to raid than a sheet metal door. Upgrade your walls before spending HQM on armoured doors unless the door is specifically protecting the TC room.

Locks

A door without a lock can be opened by anyone. There are two lock types. Use code locks. Key locks are slower to use and create a key that can be looted from your body.

Code Lock
Code Lock
100 metal fragments
Set a 4-digit code. Anyone who knows the code can open the door. Share the code with teammates, not the key. You can set a guest code for temporary access. Change the code if you suspect it has been compromised.
Key Lock
Key Lock
75 wood
Creates a physical key that must be crafted and carried. If someone loots the key from your body they can enter your base. Avoid on anything important. Fine for storage boxes or outer gates where security is not critical.
Lock every door immediately after placing it An unlocked door is an open door. The five-minute window after placing a door is when most people forget to add a lock. Code lock goes on before you walk away.

Placement and Hinge Direction

Doors open toward whoever placed them. An inner door placed from inside the base swings inward. This determines whether the open door leaves a gap facing inside or outside.

Which way the gap faces when the door is open depends on which side you placed it from.

For an airlock, this is the whole mechanic. For a standalone door, think about whether an open door gap faces toward outside where enemies can exploit it. See the airlock guide for how hinge direction is used deliberately.

You have five minutes after placing a door to pick it back up and re-place it. Door frames can be rotated with a hammer at any building tier. Fix wrong-facing doors before the window closes.

Upgrade Priority

Not every door in the base needs to be armoured. Spend on what matters first.

Airlock doors first. Both of them, sheet metal as soon as possible. They are the first thing a raider encounters and wood doors on an airlock are a quick entry for anyone with a handful of satchels.

TC room door second. This is the door a raider reaches if they get through your airlock without fully raiding. Armoured door here is worth the HQM later in the wipe.

Inner base doors last. Doors between rooms inside the base can stay at sheet metal for most of the wipe. Only upgrade to armoured when you have HQM to burn and the base is fully stocked.