Designed by Parramon + Tahull arquitectes, Casa Hostafrancs in Barcelona, Spain, transforms a dark, compartmentalised attic apartment into a more open and energy-efficient home. The original dwelling had small windows, low ceilings, and limited connections to its terrace and porch. Its roof was also poorly insulated and affected by water leaks, making improvements to the building envelope a central part of the renovation.

The roof was reconstructed while retaining its original single-slope geometry. Thermal insulation was introduced above the timber beams and existing waterproofing problems were resolved. During construction, removing the suspended ceilings revealed damage caused by wood-boring insects, requiring the replacement of the structural beams.

Improving daylight and spatial continuity

Existing openings were enlarged to bring more natural light into the interior and strengthen connections with the outdoor spaces. Internal partitions were limited to those necessary for privacy in the bedrooms and bathroom, allowing greater visual continuity between rooms.

A multicoloured stoneware floor, featuring solid tones and varying joint widths, extends throughout the apartment. Its continuous pattern visually unifies the spaces, while bespoke birch plywood furniture and joinery provide storage and functional elements without introducing unnecessary divisions. The new timber ceiling and beams remain exposed, complemented by lacquered aluminium window frames and traditional wooden roller shades that help control direct sunlight.

Reducing operational energy

The renovation improves thermal performance through additional wall and roof insulation, reducing heating and cooling demand compared with the original poorly insulated envelope. Indoor comfort is supported by steel-plate radiators and a ducted heat-pump air-conditioning system. Ceiling fans provide an additional means of maintaining comfort during transitional seasons, potentially reducing the need for mechanical cooling.