The search for integrity in the design and building process is paramount. Construction methods and materials are constantly analyzed for their honesty in both respects and, as such, the process of formed concrete as an exposed building material finds its way into much of what we do. Respected for its strength and performance in an active seismic climate, it is equally appreciated for its ability to set a contrasting stage for warmer, more expected counterparts such as fine woods, excavated stone, and integral color plaster.
We typically use what is called "board formed, cast in place concrete" which is constructed by plywood or lumber form walls that hold the concrete in it's desired form while curing and then removed to show an exposed formed structure. The process is extremely labor-intensive, as we require exacting craftsmanship in the formwork -a Japanese sense of materiality if you will. The resulting finish is of high quality and yet still echoes an industrial materiality -desired as it then serves as a stage for other, more precious materials to play protagonist.
With its indefinite service life, concrete also plays a role in our broader environmental agenda as it conserves resources and reduces the need for reconstruction. Its ingredients are cement and readily available natural materials: water, aggregate (sand and gravel or crushed stone). Concrete does not require any CO2 absorbing trees to be cut down and the land required to extract the materials needed to make concrete is only a fraction of that used to harvest forests for lumber. Concrete absorbs CO2 throughout its lifetime through carbonation, helping reduce its carbon footprint. A recent study indicates that in countries with the most favorable recycling practices, it is realistic to assume that approximately 86% of the concrete is carbonated after 100 years. During this time, the concrete will absorb approximately 57% of the CO2 emitted during the original calcination. About 50% of the CO2 is absorbed within a short time after concrete is crushed during recycling operations.
A new environmentally friendly blend of cement known as Portland-limestone cement (PLC) is gaining ground all over the world. It contains up to 15% limestone, rather than the 5% in regular Portland cement and results in 10% less CO2 emissions from production with no impact on product performance. Concrete made with PLC performs similarly to concrete made with regular cement and thus PLC-based concrete can be widely used as a replacement.