Architecture office OHLAB has renovated a historical apartment building in Palma de Mallorca introducing contemporary elements including a meandering wooden walkway that contrast with the original features.

Can Santacilia is a 3,300-square-metre residential development containing 15 apartments and common areas distributed across two adjoining buildings in the heart of Palma de Mallorca's old town.

Parts of the existing building appear to date back as far as the 12th or 13th century, although the main building as it stands was erected in the 17th century and was subsequently modified in the 18th and 20th centuries.

Local architecture and design office OHLAB was tasked with overseeing a modernisation project involving repairs to the existing structure, as well as the sensitive restoration of key original features including the main central courtyard.

"The building was abandoned and in a really bad shape with some parts about to collapse, while the best parts did not meet the most basic living conditions," OHLAB directors Paloma Hernaiz and Jaime Oliver told Dezeen.

A carefully conducted restoration process placed emphasis on maintaining the historical integrity of the building whilst adapting it to meet the needs of its new occupants.

"We had to do a thorough and intensive renovation of the whole building," the OHLAB architects explained.

"The distribution was changed and reorganised, new partition walls and layouts were added to accommodate the housing proposal and new installations were required to adapt the apartments to contemporary comfort and energy-efficient standards."

The project preserves the original features that make the building unique, such as the wrought-iron balustrades, stone columns, traditional courtyard and a wooden coffered ceiling that was uncovered during the restoration.

The courtyard was enclosed in the 20th century, with blank walls used to conceal a parking area. Based on other traditional buildings in the city, the architecture studio restored this space to how it might have looked in the early Baroque period.

The courtyard's typical staircase and porched gallery were retained and two arched openings were added – one alongside a new indoor pool and the other in front of the entrance, supported by a pair of ionic columns.

Internally, the common areas of the two buildings are connected by a wooden walkway that mitigates a height difference of approximately 90 centimetres.

The studio said the walkway was designed to take users on a journey, "as if discovering an archaeological ruin", leading them past some of the building's key historic features, including a fireplace, a stone arch, a tiled floor and ornate plaster mouldings on the ceiling.

Architectural interventions were implemented using a material palette that clearly separates them from the existing structure. The walkway was made from light oak that was also used for other circulation areas including a staircase and the lift interiors.

"We added pieces that are always clearly new and contemporary," explained Hernaiz and Oliver, "with shapes and materials that in no case want to imitate or hide the ancient ones."

The contrast between old and new is also evident in the apartments, some of which feature modern mirrored volumes used to partition the existing spaces whilst maintaining their overall proportions.

The mirrored boxes never reach all the way to the ceilings, ensuring the original wood-beam construction or decorative mouldings remain visible and uninterrupted.

"The mirror box disappears in its reflection, giving back the space stolen by its presence and returning a complete image of the room," the OHLAB architects added.

"Only when you get closer, do you realise it's a contemporary partition that lets you enter into another space, made of stone."

One of the most surprising discoveries made while stripping back the dilapidated interiors was an ornate medieval ceiling made from painted wooden beams and coffers, supported by a central stone pillar.

OHLAB claimed that this find prompted the redesign of 40 per cent of the total project, including six of the 15 apartments, in order to persevere the integrity of the coffered ceiling and incorporate it into one of the living spaces.

The palette used throughout the public and private spaces favours natural, local materials chosen to emphasise the building's history and Mediterranean character.

Stone and timber structural elements was combined with plaster and wood mouldings, mortar and lime coatings and floors in ceramic and wood finishes.

High-quality fixtures and details in local stone, bronze, porcelain and textiles including local linen and cotton enhance the premium feel across the interior spaces.

Hernaiz and Oliver originally founded OHLAB in Shanghai in 2007 before moving to Madrid and eventually settling in Palma de Mallorca, where they head up a team of 18 architects, interior designers and engineers.

OHLAB's previous projects include an apartment block in Palma de Mallorca covered with thin wooden slats that shade the interiors, and a standalone villa at a hotel on the island with a window designed to frame a panoramic view of the landscape.

The photography is by José Hevia.