A foldable support base for a foldable furniture with a flexible user support platform, in which a support frame has two side frame members, each pivotally connected to a load pivot joint along a load member with a load section extending beyond the load pivot joint which is pivotable about the first load pivot joint towards a center of the support frame. The load sections of the load members are configured for removably attaching a flexible user support platform therebetween. A load on the flexible user support platform results in a force component pulling on the load sections of the load members to cause the load members to pivot about the respective load pivot joints in a direction towards the flexible user support platform, thereby biasing to keep the side frame members to be spaced apart to maintain the support base in an extended configuration.