The garden features a new transparent pavilion with an entrance hall, museum shop and auditorium. This extension has been designed as a contemporary orangery against the monumental garden wall. The orangery is the start of the public route through the galleries in the various historical building sections. The existing listed building has been completely restored and transformed into a museum. The historic structure has been revealed more clearly by removing later additions and restoring original elements such as beamed ceilings, doors and window frames. The Stedelijk Museum is located on the ground floor and in the cellar whilst Museum Henriette Polak is on the first floor. The museums share a wing which contains galleries for temporary exhibitions. The wing has been structurally optimised in order to meet the strict climate and safety requirements for temporary exhibitions. A new staircase has been designed between the two floors, which enables the temporary exhibition space to have its own route.

The main requirements of the transformation project of the City Palace were improvement of the interior climate, enhanced sustainability of the national monument, a reduction in operational costs and excellent security. Climate, light and security systems have been cleverly integrated into the construction . The air ducts have been installed in the structural floors and walls and air is blown in through structural cracks, without grilles. Lighting is fully LED- and sensor-based, and heating is based on a low temperature using heat recovery from ventilation air. The façades have been insulated in the interior and the monumental windows have been fitted with secondary windows. On the exterior, automatically operated shutters have been installed to improve regulation of the museum climate, manage sunlight and optimise security.