Illegal. Legal basis: Article 5 of the Measures for the Administration of Residential Interior Decoration prohibits the following acts in residential interior decoration activities:

1. Changing the main body and load-bearing structure of the building without the consent of the original design unit or the design unit with corresponding qualification grade.

2. Change rooms or balconies without waterproof requirements into bathrooms and kitchens.

3. Expand the original size of doors and windows of the load-bearing wall and dismantle the brick-concrete wall connecting the balcony.

4. Damage the original energy-saving facilities of the house and reduce the energy-saving effect.

5. Other behaviors that affect the safety of building structure and use.