Renovation of Two Historic Houses Between Party Walls | Arqbag

Revitalizing Historic Homes with Sustainable Design

The renovation of two adjacent houses in the urban fabric of Terrassa, Spain, showcases a blend of historic preservation, modern architectural techniques, and sustainable construction. Designed by Arqbag, this project reimagines the potential of connected residences by merging them into a cohesive living space while prioritizing energy efficiency and bioclimatic strategies.

Adaptive Reuse: Merging Two Historic Homes

Originally built in the late 19th and early 20th centuries, these two houses were part of a city expansion effort. The project sought to transform these separate structures into a single integrated residence by utilizing their shared party wall as an architectural advantage. The approach creates a flexible, non-linear living environment that departs from the conventional rectangular home layout.

By introducing new passageways in the shared wall, the layout shifts from a traditional segmented structure to an open matrix of interconnected spaces. This allows for diverse living arrangements, improving both functionality and comfort. The renovation also expands the inner courtyard, enhancing natural light, ventilation, and green space.

Sustainable Materials and Passive Design Strategies

The construction materials were carefully selected to minimize environmental impact while improving indoor comfort. One of the key innovations is the use of compacted earth blocks (BTC) for partition walls, which provide thermal inertia and hygroscopic control, helping regulate indoor humidity levels naturally. Unlike traditional ceramic bricks, BTC enhances moisture absorption and contributes to passive cooling strategies.

Key sustainable features include:

• Enhanced thermal insulation on roofs and facades to reduce heat loss
• Shading systems to control solar gain and prevent overheating
• Natural ventilation strategies, including a chimney effect through a central core
• Optimized daylighting through skylights and motorized roof windows

Bioclimatic Design for Energy Efficiency

The renovation employs bioclimatic architecture principles to reduce energy consumption while maintaining a comfortable indoor environment. Passive strategies such as solar gain from the south facade, thermal inertia, and cross-ventilation systems significantly lower the home's reliance on mechanical heating and cooling.

Additionally, the project improves natural ventilation and lighting by integrating a central core that connects to the roof through motorized skylights. This innovation enhances airflow while allowing natural light to penetrate deep into the home’s interior, addressing the typical ventilation and illumination challenges of historic homes.

Reinforcing Structural and Environmental Performance

The renovation strengthens the existing structure while reducing the building’s carbon footprint. By aggregating the two houses, the design eliminates the need for additional service cores, instead turning the central areas into functional, environmentally-driven spaces. The thermal insulation applied to the roof, facades, and ground slab optimizes energy efficiency, resulting in a 60% reduction in renewable energy consumption compared to standard CTE regulations.

A Vision for the Future of Urban Renovation

This project exemplifies the potential of historic preservation combined with modern sustainable architecture. By rethinking the use of shared party walls, implementing bioclimatic strategies, and using eco-friendly materials, the renovation not only respects the history of the buildings but also enhances their performance and livability. The result is a dynamic, energy-efficient home that sets a precedent for future urban renovations in dense, historic environments.