Base Facilities (EU)

There are several types of base facilities that you can place in your installations. Some of these are available from the beginning of the game, others are gained through research. With the exception of the Access Lift, and the facilites you start the game with, all require an amount of time to be built and will charge you a monthly maintenance fee on top of the initial construction costs.

You can remove old unwanted facilities that you no longer use if they are empty, but if you do you should note their is a known bug that means that it is very expensive to keep around empty squares that used to be occupied.

All base facilities must be linked, either directly or via other base facilities, to the Access Lift. While you cannot dismantle a base facility that is in use or is linking other facilities to the Access Lift, it can be destroyed in the process of a Base Defense mission. If a base facility is destroyed in this way, any other base facilities that were relying on that facility as a link to the Access Lift will also be destroyed. Any pieces of equipment, craft, or personal will, however, remain in the base (despite the lack of room).

Initial vs. Researched Facilities

Initial Base Facilities:

Researchable Base Facilities:

Quick Cost Reference

Structure	Construction Cost	Maintenance Cost *	Construction Time	Stackable?
Access Lift **	$300,000	$4,000	1 day	No
Living Quarters	$400,000	$10,000	16 days	Yes
Laboratory	$750,000	$30,000	26 days	Yes
Workshop	$800,000	$35,000	32 days	Yes
General Stores	$150,000	$5,000	10 days	Yes
Alien Containment	$400,000	$15,000	18 days	Yes
Hangar	$200,000	$25,000	25 days	Yes
Small Radar	$500,000	$10,000	12 days	No
Large Radar	$800,000	$15,000	25 days	No
Missile Defenses	$200,000	$5,000	16 days	Yes
Psionic Laboratory	$750,000	$16,000	24 days	Yes
Hyper-Wave Decoder	$1,400,000	$35,000	26 days	No
Laser Defenses	$400,000	$10,000	24 days	Yes
Plasma Defenses	$600,000	$12,000	34 days	Yes
Fusion Defenses	$800,000	$14,000	34 days	Yes
Mind Shield	$1,300,000	$5,000	33 days	No
Grav Shield	$1,200,000	$15,000	38 days	No

* These are the maintenance costs listed in the game, but in fact these are all incorrect. They depend solely on placement in the base. See the Maintenance Cost Bug, below.
** GEOSCAPE.EXE says the Access Lift takes 1 day to build and costs $300k, but in fact it is constructed instantaneously, and its cost varies depending the region of Earth where you choose to place it.

Caveat re: Single Use Facilities

Normally, the more base facilities you have, the more you are able to do with them. This is not so for certain facilities, even though it isn't obvious in the game. For these, only the first facility provides any benefit to the base. They are: The Small Radar, Large Radar, Hyper-Wave Decoder, Grav Shield, and the Mind Shield. It is also possible that you only need one Alien Containment; this needs more testing.

The above facilities work with other facilities, but any duplicates won't provide any additional benefits (while still costing maintenance). This is especially important for the Grav Shield and for Radar. The Grav Shield will only repel attackers once per base, no matter how many you have (so one is all you need). Likewise, a second Large Radar doesn't provide any additional large-radar functionality, but a single Large Radar and a Small Radar will stack and combine their scanning abilities.

While the base information screen does list how many radars you have, that's all it effectively does - It does not represent your base's actual scanning ability. Further, once you have a Hyper-Wave Decoder, you do not need any Small or Large Radars, and can dismantle any you have. The Decoder has a wider range and always detects alien craft immediately, unlike either Radar. (But watch out for Paying For Dirt when you dismantle radar.)

The only reason to build multiples from the above single-use list would be for strategic base defence reasons, as each module provides a different lower corridor layout.

Facility Maintenance Cost Bug

XCOM has an interesting bug: When tallying maintenance costs, the code erroneously passes on the row number of the base that the facility is found in, instead of the record number for the facility. As seen in BASE.DAT (and as evidenced by, e.g., their order in the in-game UFOpaedia), the first six base facilities are:

Record  Facility           Maintenance
  00    Access Lift            4k
  01    Living Quarters       10k
  02    Laboratory            30k
  03    Workshop              35k
  04    Small Radar System    10k
  05    Large Radar System    15k

Due to the bug, this leads to base facilities costing you monthly maintenance depending on their placement, as follows:

	C1	C2	C3	C4	C5	C6
R1	4	4	4	4	4	4
R2	10	10	10	10	10	10
R3	30	30	30	30	30	30
R4	35	35	35	35	35	35
R5	10	10	10	10	10	10
R6	15	15	15	15	15	15

Hangars are only charged once, for their upper right (upper left?) square. So a Hangar along the "bottom" of your base would cost $10k/month.

Due to the bug, all the maintenance costs listed in the UFOpaedia are effectively wrong. However, the Geo finance Graph does get the total correct.

If you are looking to save money, clearly it's cheapest to have a strategy that puts a defensive buffer along the third or fourth row:

The above layout costs $329k/month: The hangars on the bottom are 3*10, the lift is 35, and the rest is 6 * (30+10+4). Replace all the Psi with whatever you like, it's irrelevant. Also, the Lift could be anywhere on its row.

This layout costs $402k/month, $73k more expensive than the first one, despite having precisely the same facilities.

So a design with hangars along the bottom is the most cost effective for a "full" base. Small outpost bases have more options available.

Note: This bug has the dubious honor of being a fairly straightforward, important one which went unnoticed for a dozen years until Sfnhltb caught it in February 2007. For more info, see this page's Discussion.

Paying For Dirt Bug

If you take down a facility and leave bare dirt, you will continue to pay maintenance on it. But not at the old rate; filling the hole back with dirt means it needs special attention at all times by specialists. In fact for every square of dirt you have that used to be a facility you will pay $80k/month. Thats $320k per hangar you take down.

There are only two known ways to stop paying this premium: 1) completely dismantle the base, or 2) build over all the spaces that you have vacated. In fact as soon as you start building the new facility you stop paying the premium, as well as not having to pay the cost of the new facility until it is complete.

Note: If you start a facility and change your mind before it is complete, after the time it would have completed you will start paying this $80k premium!

Base Construction Quick Notes

Destruction of base facilities through combat and the domino collapse effect - To Do
Base Disjoint Bug - in progress

For More Information

A number of topics involving bases are discussed elsewhere. See:

Xcom_and_Alien_Bases#XCom_Base for images of all base facilities.
Base_Layout_Strategy discusses base defense tactics. X-Com_Base_Terrain addes a few more thoughts.
Base_Defense describes base defense at a more strategic level.
The UFO_Base_Kit, for designing your own base layouts!