A few years ago, the Balearic Housing Institute IBAVI initiated a collective laboratory for climate-neutral building by means of a consistent, sustainable housing construction programme. While these buildings provide urgently needed living space, they are also examples of hybrid construction methods. They reflect regional building traditions and reveal the innovative strength within this programme. For instance, for an apartment building in Palma Harquitectes reused material from a demolished building that stood previously on the site. Chunks of stone were cast in lime cement and then cut into blocks to be used for the new building. In contrast, the apartment block by López Rivera in Esporles is reminiscent of traditional mixed construction methods. The layer of loggia-like access decks on the courtyard side and parts of the adjoining building that houses the staircase were built of limestone. Similarly, in Inca Estruch Martorell built a facing layer of natural stone, while for the lintels and the ceiling slabs they used concrete and wood.