One of the outstanding features of the design of Il Redentore is that it achieves an overall unity through a skilful arrangement of autonomous parts. This quality, which can be seen in the layout of the plan, in the harmonious succession of volumes and in the layered composition of the façade, is the result of the fine balance that Palladio achieved in his mature design. Each part has its own compositional root, subordinated to a longitudinal order that makes it possible to achieve a homogeneous space.

The church had its origins in a declaration of the Venetian Senate, which proposed its construction to commemorate, with an annual procession, the end of an epidemic that had killed more than 40,000 Venetians. The building had to harmonise with the slanting view of St Mark's Square offered by the site. For this reason, Palladio was asked to design a central plan, which was discarded because some members of the Church objected to the pagan origin of the shape, and another in the form of a Latin cross, which was finally approved by the authorities. Palladio's project, although following this form, combines a rectangular plan with a central one.

The first part of the building has a rectangular nave with three chapels on each side. There are no side aisles and the chapels open onto the wall through barrel vaults. Palladio rejected the medieval tradition of column supports and adopted a technique from Roman antiquity, supporting the vault with moulded walls. A rhythmic series of Corinthian columns support the continuous cornice, which gives unity to the space. The bases of the columns are lower than usual so as not to obstruct the view and to support the unified character of the nave. Above, windows under the vaults flood the space with light. At the end of the route, a column on either side of the opening reconstructs the rectangular shape of the nave and marks the passage to the next room.

The second bay has the characteristics of a circular space, although it is a triconque structure. It is a transept that supports a dome. The tribune is located in this room. To the left and right of the axis, the wall takes on a semicircular shape. The third side of the triconque is a screen wall made up of four columns that Palladio inserted to limit the space of the choir without breaking the spatial unity of the whole.

The third section, virtually separated from the church, is more modest and enjoys greater privacy. It retains the width of the nave, but is lower. The side walls are joined at the end in a semicircle, maintaining the axial hierarchy of the space.

Externally, the progression of the volumes forms an indissoluble morphological unity. The parts are modelled plastically, avoiding any contrast. The external brick wall is decorated with applied columns. The buttresses that rise above the roofs of the chapels maintain a rhythmic order until they reach the dome, which is supported by two towers on either side to reinforce the unity of the composition.

The façade is a quasi-pictorial composition of superimposed planes. The main façade is set against a rectangular attic. It contains a smaller one framing the entrance door. Behind it, a lower and wider one follows the space of the chapels. On a level behind and below the attic, two half pediments repeat the shape of the buttresses. The entire façade rests on a podium that extends outwards across the width of the nave to open up the transition area.

Palladio designed a building with an unprecedented dynamic tension. The criterion of sequentiality in the volumetric layout, the spatiality of the interior, the layout of the ground plan, the criterion of functionality and the composition of the façade constitute a compositional lesson that distinguishes Palladio's architecture from the rest of his contemporaries.

Marcelo Gardinetti