An umbrella base is typically a cylindrical object that lies under a patio table and has a recess or hole in which the pole from a umbrella is held and secured. It is typically heavy enough to keep the patio umbrella from being disheveled or lifted away by the wind.
Some of these bases are plastic and hollow, which enable the owners to fill them with water or sand in order to weight them down for this purpose. Others are made of heavier materials such as iron or cement.
It is important that the umbrella base has a wide enough circumference to allow it to adequately hold the patio umbrella in place without the danger of allowing it to rock back and forth. Additionally, the umbrella cannot be so wide that it hinders the movement of the patio furniture chairs under the table.
Typically, an umbrella base will be two or three feet wide if it is an empty plastic or resin base that is hollow enough to fill with sand or water. Cast iron or steel patio umbrella bases can be smaller as long as they are hefty enough to stop the patio umbrella from swaying.