The short answer
If your living room comfortably fits eight children sitting down, it fits a pamper party. Around 16ft by 16ft is the comfortable size. Below that it still works, we just spread one or two activities into a nearby room so nobody is on top of anybody else.
What you actually need
Somewhere for the girls to sit with their feet down for the foot spas: a sofa, dining chairs, or the floor. Plug sockets. Access to water, because the foot spas need filling and emptying. And a room that can be aired, since eight children and a room full of activity gets warm quickly.
Tables
A dining table is useful but not required. We carry small fold-out tables that sit at floor height, which the younger ones tend to prefer anyway.
What you do not need to do
Move your sofa. Clear the room. Cover the carpet. Buy anything. We work around what is there, and we put it back.
Flats and smaller homes
Both are fine. Tell us about stairs, lifts or parking when you book so we can plan the unload, and we will make it work.