The concept of building components to be assembled off site and shipped onto the project ready to final placement is known as prefabrication, so we can say that prefabricated façades are made by panels which are manufactured in a warehouse and the dropped off at the site just in time to be put in place. These panels could be structural or not, in fact, prefabricated façades are defined as: “An outer covering of a building in which the outer walls are non-structural, but merely keep out the weather”.
Prefabricated façades are an alternative to other traditional enclosures due to their quick installation, but also for its
– Resistance to support their panels own weight, wind pressure and temperatures .
– Weather barrier, they must be carefully designed in order to make a waterproof and windproof façade.
– Achieve a good comfort indoors.
– Fire prevention.
There are lots of different classifications based on different properties of prefabricated façades, but we will focus on a structural point of view. There are two main groups:
– Lightweight façades, which are not fixed directly to structural elements of the building,. It is necessary to add some auxiliary structure between panels and columns or other structural element which has to support the façade.
Auxiliary structure could be made by stainless steel, aluminum even wood, although last one is uncommon.
Lots of factors contribute to the failure of these façades, some more harmful than others. Joints are totally related with each other, if one doesn’t work as it should damage the others. However the most common cause of failure is related with corrosion of structural elements.
– Heavyweight façades, which are the opposite, these are fixed directly to building structure, they don’t need auxiliary support.
Usually are compound by concrete panels, which are thicker and heavier than the previous.
These panels could combine structural and architectural requirements in a huge range of possibilities.
Environmental factors are which contribute most to the failure of façades. Moisture could be the responsible of lots of damages because it contributes to anchor deterioration. Another cause could be produced mixing the effect of water, low temperatures and cracks.
According to all this, when we need to choose a type of prefabricated façades, we need to fix the specifications of our building, in order to select a type of panels, and then try to choose the option that will support better the conditions at which the building will be exposed.
Lizama Velázquez, Sara.