Briefly, structural masonry is a construction system in which the walls of the building perform a structural function, using masonry units arranged in a way that is self-supporting and load-bearing. The walls will evenly distribute the load to the foundation and later into the ground.
Stacked in layers, the bricks, blocks, or stones may or may not be connected by a binder (mortar) and steel reinforcements that heavily influence the mechanical properties of the wall, dimensioned to resist active forces.
A course is a continuous row of any masonry unit, such as bricks, concrete or ceramic blocks, running horizontally in a wall. Several courses form a wythe, which is a vertical section of masonry one unit in thickness. A single non-structural wythe of brick is referred to as a masonry veneer. A course can be filled with steel reinforcement and grout to create a lintel, sill, or bond beam, binding and integrating the masonry wall into a stronger unit.
How does it work?
Tradicional column-beam systems use timber formwork built on-site according to the architectural project, forming molds into which steel reinforcement is added and concrete or similar materials are poured. After the concrete sets, the molds are removed leaving a structural skeleton, which is then complemented with walls that can be made of many different materials. This envelope has the sole purpose of enclosing the building and providing thermal and acoustic comfort. Plumbing and electrical systems are normally installed by cutting chases on the finished walls, which is a very inefficient construction process of building up an entire wall only to open it up again for pipes and conduits.
In structural masonry, however, there is no framing, and the courses of units are laid precisely according to the architectural plan. Different types of concrete or ceramic units fulfill specific functions in each project, and they are normally bonded together with cement mortar. Hollow blocks are more common in construction and much more efficient because the vertical holes can be used to carry services such as electrical conduits and pipes, with no need of chasing, and U-shaped units, for example, can receive horizontal reinforcement.
This integration of the electrical and water systems into the building structure is one of the main advantages of structural masonry, saving time and money. This type of construction is faster and reduces construction waste, allowing for highly organized construction sites. Also, by using fewer materials such as wood, steel, and concrete, construction is much more cost-effective, using standardized components that allow the project to be easily built and replicated through modulation.
Modulation in architecture means adapting the project to the measurements of specific building materials, such as bricks and blocks. By using this metric, the construction logic is incorporated into the design process, and the outcome is a much more efficient and sustainable building.
This is very evident in projects such as the Heliópolis Social Housing by Biselli Katchborian Arquitetos, a housing complex in São Paulo with 420 units of two different types carried out as part of the Slum Upgrading Program of the City of São Paulo, through the Department of Housing. The six-story buildings are all built with structural masonry, and the modulation can be seen clearly in the unit's floor plan and in the way it is replicated to form the typical floor.
Another project where this happens is the COPROMO, a community housing by Usina CTAH's technical advisory group. This project uses structural ceramic blocks, which is very common in self-managed housing cooperatives since the 1990's because it is a lightweight building material, making it easy to handle on the construction site. The floor plan of the units is based on the size of the blocks, leading to the arrangement of the typical floor, which is then replicated to create the overall building complex, thus ensuring optimal construction and also visual identity.
Apart from modulation, structural masonry also allows the incorporation of other structural elements, such as retaining walls, to the architectural design, as seen in the Half-Slope House / Denis Joelsons + Gabriela Baraúna Uchida, which is split into two sections because of the steep terrain, creating an interesting effect while also ensuring technical support. Additionally, structural masonry can be combined with other systems when needed, like in the Vila Maida Housing Complex / Maristela Faccioli, for example, that also features beams, columns, and steel structures alongside the load-bearing masonry planes.
One of the biggest disadvantages of using structural masonry is that floor plans are not very flexible because load-bearing walls can't be removed for renovations unless the structure is replaced by a new beam, for example. The CL Warehouses by VAGA, however, show that it is possible to use this construction system and still achieve some flexibility. This project was designed to serve many purposes, so the modulated structural walls were arranged to support long-span slabs for the roof and mezzanine without the need for complex structures, thus providing lots of open and flexible space.
By understanding the process of building with structural blocks, it becomes clearer that this solution is not as stiff as it seems but actually allows for unexpected and unique designs, as we can see in the Headquarters for a Block Factory by Vão. According to the architects, it was during a visit to the warehouse and from observing the storage and transportation system of the blocks that the idea of building without the use of mortar materialized. From there, the relationship between height, weight, and contact area of the stacks was explored in both the project and in the prototypes at the construction site, resulting in a structural masonry building with great stability, quick assembly, and unique architectural language.
Structural masonry provides a more optimized construction while also saving resources, money, and time, which is why it has been increasingly popular, even for higher residential buildings. This system can create new perspectives in the field of architecture, not only regarding the material palette and construction technique but also in terms of the architectural design process.
Check out this selection of Brazilian houses using structural masonry for more inspiration.
