written by: Tanya Davis, AIA
Natural stone has long been a favorite material for both exterior building cladding and interiors for floors, countertops, base and accents. Granite, limestone, slate and marble are all examples of the range of stones commonly specified. VCBO has some fantastic award-winning stone projects: Park City Medical Center Expansion, Montreal Temple, City & County Building, Utah State Capital and the doTerra campus. Whether classical or contemporary, hand carved or stacked, natural stone is a complement to the architecture of the mountain region.
Specifying natural stone is fairly simple, but the journey of a stone from quarry to job site is anything but. On a recent project, I had the opportunity to observe this operation from start to finish and it was an eye-opening look into a multi-faceted process. Typically, as designers, we begin with a finish sample that reflects a particular color palette, approved by the owner. With natural stone, no two samples will ever be the same so a range sample is necessary. We work with the owner and a vendor to identify a range of samples of color, movement, veining and occlusions that would be considered acceptable. These range samples are smaller scale, often 12”x12.” Once a range is approved, it is time to visit the quarry where the stone is extracted.
Our team visited a quarry in Portugal to identify range samples and acceptable limestone blocks. This time the range samples are full size slabs cut from a typical 20-ton block for review. The size and scale of the quarry is hard to describe – it is massive.
The quarry has multiple grades of the stone available within different sections. For the on-site range review, it is vitally important for our team to carefully outline which sections of the slabs are acceptable and which are not. This process narrows down which parts of the quarry are approved for use on our project for block selection. Once approved, the rest of the blocks can be selected from a similar area of the quarry and shipped to the fabricator. These blocks are gigantic, the size can vary greatly but one block can fill an entire shipping container. Here’s a quick video clip of one 40-ton stone getting loaded on a flatbed truck in the quarry, a process which took almost ten minutes to complete.
Two days before we arrived on site, the subcontractor had felled a wall of stone blocks in the quarry onto a bed of stone rubble below. The workers described the sound like a giant thunderclap which vibrates through your entire body. This would have been an amazing sight to see and hear. From the quarry, the stone is shipped across the world sea to fabricators, typically in China or India.
Our team visited a fabricator in China and had the opportunity to see blocks of limestone being cut down into 4cm veneer stone for the face of the buildings as well as cubic stone to wrap the corners and profiles. An entire wall section was laid out on the floor for preliminary review. Below is a video montage of the process of cutting the stone from large blocks to successively smaller pieces.
Even specialty details like decorative carved panels are easy for this team. They start on a CNC machine and finish with a highly skilled team of hand carvers. Finally, the stone is shipped to the project site where it is installed by a masonry craftsman. From creative color palette inspiration to installed stone, it is quite a journey for natural stone, sometimes encompassing an entire trip around the globe. Stay tuned for a future blog post that will explore how those beautiful decorative panels go from sketch to stone.