How much terrace space does an umbrella base take up?

Enough that the base should be set out on the plan rather than discovered on site. Our footprints by type:

• Resin centre pole bases: 42.5 cm, 44.5 cm, 50 cm and 53.5 cm diameter, with heights from 8 cm to 34 cm
• Steel-plated concrete centre pole base: 55 cm diameter and 45 cm high
• HDPE interlocking cross base: 50 x 50 x 7.5 cm
• HDPE square fillable bases: 85 x 85 x 17 cm and 97 x 97 x 19 cm
• HDPE base with handle: 90 x 90 x 21 cm
• Welded marble base: 145 x 120 x 20 cm

A square or cross base at 85 to 97 cm per side is roughly the footprint of a cafe table, so where tables are set 60 to 80 cm apart a base of that size changes the seating spacing. The low resin bases, at 50 cm diameter and 8 cm high, are the ones to choose when the base has to disappear under a table.