Historically, concrete has been one of the most enticing materials for architects to work with. In the post-War economy, what started off as an inclination towards economic purposes soon turned into an architectural medium. It became a favorite among the doyens of urban planning, such as Le Corbusier, to experiment with the remarkable adaptability of concrete, with its sculptural and structural potential.
It wasn’t long when prefabricated concrete became one of the solutions to recover the dire state of housing after World War I. It was affordable, yes, but was also a depiction of a material in its rawest, most honest form. The precast concrete has now become one of the most commonly — and arguably the most favorite — architectural medium just because of a production value that is conducive to a controlled, industrial process along with a modernist aesthetic.
The material is best seen in the form of floors, walls and even roofs in domestic construction that ranges from independent residences to multi-story apartments.
Types of Precast Concrete Systems
Also known as curtain walls, precast concrete cladding serves the purpose of creating ‘envelopes’ — a type of panel that brings an element of closure to spaces. Since concrete is engineered in such a way that it can withstand any form of seismic force, these claddings exist to resist any force of the wind. They usually come in the form of column covers, spandrels, wall panels, mullions and window wall units.
Load-bearing facades bring to the architects and builders the option of creating something that is not just structurally sturdy, but also has an aesthetic function. These walls have also been employed architecturally, in order to rehabilitate old buildings or renovate them. Bearing walls can be found in the form of solid, insulated or hollow core. While flat surfaces are usually the norm, precast concrete walls are especially conducive to curved surfaces.
Shear walls are known for their inherent quality to resist seismic forces, such as strong winds, and their performance as vertical members is one of the most significant foundations of a structure.
Benefits of Precast Concrete Walls
Aesthetics aside, the precast concrete wall has been perfected over the last few decades, for the sole purpose of maintaining a sturdy construction. Let’s look at the benefits of this medium.
Resists Harsh Conditions
The precast concrete material has been
designed to enable the strict requirements for thermal insulation. Fundamentally, concrete is conducive to insulation, which keeps the interiors warm during cold temperatures and cool when it’s raging hot. Its natural stabilizing tendency makes it an ideal material, especially in tropical countries.
Additionally, massive panels can be used as acoustic barriers because its surface is designed to absorb traffic noises. Sandwich wall panels have been proven beneficial as facades in wood drying
plants with a relative humidity of 100 percent inside the building. The material makes living in uncomfortable conditions possible.
It Has a Long Life
Concrete lasts. If one has to calculate a built precast concrete structure’s age, it could easily go up to about 200 years. This is linked to its endurance of harsh climatic conditions.
Conducive to Experimentation
Since precast concrete comes in many forms, it makes the architect or the user experiment with its various textures and panels — from plastered sandwich and inner layers to cladding panels. Additionally, the material comes with flexibility in its color, ranging from white to grey. One can add paint or pigments, according to the desired space.
As Le Corbusier had intended, precast concrete can be molded into any form and shape. The molds, additionally, can come in various forms such as timber, steel, plastic, rubber or fiberglass. Each of these molds can create a unique finish.
An Innovative Medium
Talking about moldable properties, try the famous Finnish innovation — which involves precast walls with graphic concrete patterns — which is manufactured by placing a printed membrane into the mold. This can further be improved through polishing, hammering, acid etching and sandblasting, all of which is applied to hardened concrete.
The precast concrete facade also poses new challenges when it comes to innovative methods. One will find that in plastered sandwich walls, for instance, the facade seams are not visible. This is because joints can be hidden by positioning the windows, balconies and doors in order to break the lines. This creates an effect of seamlessness in the space.
Beauty in Uniformity
Precast concrete construction allows for certain uniformity, which is ideal for large-scale construction.
Challenges Posed by Precast Concrete Walls
Every material comes with its own mixed bag of complications. Let’s take a look at that aspect now.
Prone to Modifications
Because of treatments such as sandblasting or acid washing, the precast concrete is susceptible to abrasions or modifications on its surface. Different finishes can wear off the original component of the material and over time, its ability to protect the surface from moisture may weaken.
Complicated Finish Results in Complicated Process
In the case of a surface that has been treated with the purpose of creating an architectural impact, the precast concrete will require way more work than is necessary. Complicated profiles of the finishes usually mean more in terms of work while preparing the concrete mix and, most significantly, the surface repairs and maintenance that follows after the production.
When it comes to precast panels, which often involves variants of depths on the surface, more care and effort needs to be put in with regards to the concrete layer over the reinforcing steel. In short, the more complex the texture or cladding, the more grueling is the process. It is essential for the architect or user to be aware of the processes before embarking on a quest to execute such finishes.
Prone to Poor Construction
Because of the tendency to treat precast concrete rigorously — often with the belief that the multiple textures will result in the desired aesthetic — the wall system can give in to issues with erection, anchoring or deterioration of the embedded reinforcing steel. There have been instances of the cracking of the panel and other forms of distress when the anchoring is not efficiently done. This poses the danger of poor construction and, consequently, poor quality control, most of which will not be visible for years, until the damage is at its peak.
As much as precast concrete walls prove to be a visually pleasing sight, it also comes with the trouble of maintaining the said beauty. Sealants are essential for the structural joints and protection. In case of concrete coating, several instances of the application are required to make sure the finish adheres to the desired purpose. Furthermore, the erection of the said structures requires specialized equipment and trade, resulting in the use of excess energy and manpower.
Not Entirely Disaster-Proof
Sure, it saves you from strong winds, but in case of fire, precast concrete wall systems are no better than cast-in-place concrete.
From what started as a post-War application, the precast concrete system has now come to encompass sustainable materials to make the process eco-friendly. Given that construction and demolition have become an inevitable consequence of human activities, these sustainable methods
make sure that it tackles three environmental issues — reducing greenhouse emissions, increased resource efficiency and minimizing the use of regulated chemicals.
Precast concrete walls bring together structural, functional, aesthetic and financial elements, all in one place. It brings vibrancy to a three-dimensional reality and ensures that it stands the test of time. It opened up a world of possibilities for several architects and continues to do so even today. The material demands utmost care and precision, and the architect or user must adhere to its demands in order to ensure that your space is not just aesthetically remarkable, but also serves a foundational