Concrete and PVC - a promising marriage

Method of construction combines speed, reduction of labor, time and cost saving and can be used in applications ranging from popular housing to multiple-story buildings.

By: Cleide Sales

Combining high productivity with a reduction in cost of labor, the building system that uses PVC frames filled with concrete, internationally known as the Royal Building System, is an alternative that has been gaining market share in Brazil, innovating the way we design and build. The technology was developed by Royal Group Technologies in the early 1980's in Canada. The system arrived in Brazil in 1998 with the construction of a school in the city of Macaé in the state of Rio de Janeiro, and now accounts for over 500,000 m² of constructed area in various types of projects - from social housing under the government’s "Minha Casa, Minha Vida” popular housing program, to industrial pavilions, and multi-story buildings, stores, schools, and upper-tier homes. In Brazil, the largest number of works using concrete and PVC (Concrete-PVC forming system) is concentrated in the country’s South Region, especially in the state of Rio Grande do Sul.

The Concrete-PVC forming system technology uses a very simple concept. It is a modular system consisting of lightweight PVC panels, which rapidly and simply attach to the building modules and come in various thicknesses and heights as required by the project, that are filled internally with concrete and structural steel (rebars).

According to Tiago Saretta Ferrari, architect at Royal do Brasil S.A., programs like “Minha Casa Minha Vida” have been driving the offer of this building system throughout Brazil. “Industrialized systems are a trend and constitute a viable alternative for all levels of construction. Cement-based systems are the most widely used, and it is in this group that we find the Concrete-PVC system which has guaranteed its space in the market in a scenario where large-scale projects require speed, quality and control with costs suited to the market,” he states.

The Brazilian federal government’s social housing program has adopted this method of construction which is already being implemented in 12 of the nation’s states: Alagoas, Bahia, Espírito Santo, Goiás, Mato Grosso and Mato Grosso do Sul, Minas Gerais, Paraná, Rio de Janeiro, Rio Grande do Sul, Santa Catarina and São Paulo. Just recently, a major initiative utilizing the system began in the city of Bom Jardim (RJ) where this mountainous region’s largest storm-related catastrophe happened in early 2011 destroying several homes. Using the Concrete-PVC system, 350 popular housing units will be constructed in a brief period of six months.

Advantages of the Concrete-PVC system
This new way of building has increased competitiveness due to its various advantages compared to the conventional system. Starting with assembly: the reduction in the cost of labor is approximately 70% compared to the conventional system since neither heavy equipment, such as cranes, nor special tools are required.

The formwork that makes up the system is very light (from 8 kg to 14 kg/m2) facilitating the assembly process even in hard to reach places such as land with a challenging, irregular topography, for instance. It is a diversified solution, regardless of geographic location or climate of the region, as well as having applications in buildings for private use or of public and social interest.

According to the ‘Associação Brasileira de Cimento Portland’ (ABCP - Brazilian Portland Cement Association), a consultant on the Concrete-PVC system in Brazil, for the construction of 20 housing units with approximately 43 m² each, the estimated time for completion of the work is 30 days - at an average cost of R$ 480.00/m² (US$ 240,00 per sq. meter) and a workforce of 24 workers.

Another advantage of the technology is that it is a ‘clean’ form of construction; no rubble or debris and no waste (reduction of approximately 90% compared to conventional works), besides the fact that PVC can be recycled. Furthermore, there is also savings of up to 73% in electricity and 75% in the consumption of water construction, which makes it highly sustainable in terms of environmental conservation.

“The PVC used in this system of construction makes the walls impervious to ultraviolet rays and to variations in temperature. Furthremore, buildings constructed with the Concrete-PVC system provide an excellent level of thermal and acoustic comfort,” explains Tiago Saretta Ferrari of Royal do Brasil S.A..

How it works
The walls are anchored with the use of frames that are fastened with sinkers to the foundation which is calculated according to the typology of the building and soil characteristics.

The faces (outer surfaces) of the PVC profile constitute the final finishing of all the walls which, therefore, do not require coatings or paint. However, it is possible to optionally apply other types of finishing materials to these surfaces such as paints, textures, tile, granite and others.

The electrical installation must be executed at a time prior to concreting of the walls. The technology has its own system for the passage of wires and cables consisting of a specially shaped conduit located inside the panels. One can also use rigid or flexible electrical conduits provided the respective project definitions are observed. As regards water and pipes, all points of plumbing for water and sewage must be provided for in the execution of the foundation.

The concrete used in filling the PVC panels should be of the type that is the most appropriate for the structural and sealing function for which it is chosen and with resistance of 10 to 25 MPa. One can use conventional, self -leveling, or lightweight concrete blended with shredded Styrofoam (polystyrene foam) or even with construction debris, provided it has the appropriate resistance, slump of 25-26, and class "0" gravel or grit.

The system is open and modular and, therefore, the technology is suitable for any type of blue print or layout and is used in projects that call for a large number of units (over 1,000 houses) or even in specific projects such as 1-10 houses, for example.