Support Cap is a standard resource available to all races. Often named Vehicle Cap (though the technical name is Support Cap), this resource is essential to requisitioning some of the toughest and most powerful units in a race's arsenal, ready for destruction. It is represented by .
Each time a Support unit is requisitioned, it requires a certain amount of Support Cap. That number is seen in the description of the unit. It is impossible to go over the Support Cap limit, however. Every race has a maximum Support Cap limit of 20. This means that the combined value of all Support units cannot surpass 20.
Support Cap can be increased with the use of research (for human races) or buildings. If a building is required to build Support Cap, this will be written in the description; for example, the Kauyon and Mont'ka Command Posts both used by the Tau Empire are used to increase both Squad Cap and Support Cap.
In some rare occasions, for example when the Eldar use the Avatar, the Support Cap will go beyond its limit. However when an event like this happens, the requirements to keep the new limit constant MUST be fulfilled - in this case, the Avatar must remain on the field. If the Avatar is killed, the player will keep all units that were built, but can build no more units if Support Cap limit has been exceeded.