For most of architectural history, stone was the structure. Today it is almost always a cladding: a 3 cm veneer hung from a concrete frame. Over the past two years, our research group has been studying whether load-bearing stone can return as a realistic, low-carbon alternative for buildings up to six storeys.

The arguments are compelling. Quarried stone has a fraction of the embodied carbon of concrete or steel. It requires no curing, no formwork and almost no finishing. It lasts for centuries and can be dismantled and reused.

What we tested

Working with two quarries in Portugal and one in Switzerland, we tested compression and shear performance of limestone blocks with dry and lime-mortar joints, and developed a small set of standard block dimensions that can be cut efficiently from typical quarry beds.

The results confirmed what historic buildings already show: for compression-dominated structures, limestone performs well above the requirements of residential and small commercial buildings. The challenges lie elsewhere — in lateral stability, in thermal bridging at the floor slabs, and above all in the lack of contemporary codes and contractors who know how to build in stone.

Quarried stone has a fraction of the embodied carbon of concrete, and it can be taken apart and used again.

Casa Alba and the Stone Exchange are the first studio projects to put this research into practice. Both use load-bearing stone for their primary walls. We will publish the full findings, including costs, in early 2027.