Is it illegal to put containers on the rooftop?

This is an illegal building. You need to go through the relevant formalities at the housing management office.

Legal basis:

Measures for the Administration of Residential Interior Decoration Article 5 The following acts are prohibited in residential interior decoration activities:

(a) without the consent of the original design unit or the design unit with corresponding qualification grade, changing the main body and load-bearing structure of the building without authorization;

(2) Changing rooms or balconies without waterproof requirements into bathrooms and kitchens;

(3) expanding the original size of doors and windows of the load-bearing wall and removing the brick-concrete wall connected with the balcony;

(four) damage to the original energy-saving facilities of the house, reducing the energy-saving effect;

(five) other acts that affect the safety of building structure and use.

The term "building subject" as mentioned in these Measures refers to the structural structure of building entities, including roofs, floors, beams, columns, supports, walls, connecting nodes and foundations.

The term "load-bearing structure" as mentioned in these Measures refers to the main structural members and their connecting nodes that directly transfer their own weight and various external forces to the foundation, including load-bearing walls, uprights, columns, frame columns, piers, floors, beams, roof trusses and suspension cables.