Do you know what differences exist between W and calhetão tiles? According to Júlio Tavernaro, specialist in fastening systems and responsible for Spin's commercial area, many confuse the two, as they have major differences.
W tiles in prestressed concrete are made of steel and are normally used in warehouses, where it is necessary to have a large free space, without having columns that would hinder the movement of forklifts, for example, inside the building.
“However, many think that because it has a thick layer, concrete with a thickness of 4 to 6 cm and a prestressed area in the side gutters, it could 300 kg on top of it. It can't handle it, especially because all the resistance there is has already been used for the most part to be able to overcome this large free space. In this case, they are designed to work with 20 kgf/m² of accidental load – when there is a load caused by people walking on the roof or by rain and wind – and 30 kgf/m² of permanent load – for domes, luminaires, ceilings and other utilities . However, it is necessary to assess whether there are no longer materials ed and anchored in the tile”, explained Tavernaro.
According to the expert, customers end up confusing the look of W tiles with calhetão and install counterweight beams and triangles to obtain better radiation. “This will cause an aerodynamic effect – tension on the roof – as it was not designed to receive this type of load. Normally, the projects we develop of this type are done with the smallest possible angle of 5 degrees, so that there is no effect of the wind on the enlarged module, the so-called hang glider effect”.
Regarding the calhetão roof, it is made of asbestos-free fiber cement and with CRFS technology (Cement Reinforced with Synthetic Threads). It also has a modern profile, which favors the design of different architectural solutions, both in roofs with large free spans and in lateral enclosures.
“In it, we work with a free space of a maximum of 7 meters between the points. This tile also cannot have any permanent weight. When you put a weight on it and create a force, you go against the filament, against the process that created the tile, thus causing a lateral rupture. So, each tile has its characteristics, some are more robust to withstand bad weather, others are not”, commented Tavernaro.
Therefore, to differentiate them, the specialist explained that when the client stands in front of a roof and observes a high thickness, around 4 cm, for example, it is W tile. When he notices a low thickness and a wavy geometry , it’s calhetão.
Answers of 3
Good evening, Donizete, you are correct. You must create beams, so that the gaps covered by the calhetão tile are small. This way, they will the solar s, without any problems. I have had this type of roof for decades. I want to see if it is possible, to fix solar s on these tiles, WITHOUT using these aluminum rails, just using intermediate and end fasteners, with longer screws, capable of going through the double thickness of the tile flaps.
What is the name and/or model of this aluminum profile used in this tile?
Good article, I liked it! but we didn't talk about the photos that show the solar s, how far they can be used in the calhetão and whether, by placing a beam in the middle, this really minimizes the stress on the calhetão's fibers.
I'm replacing my roof and I'm going to use a 5 meter slab. (area of 5 x 10, including the eaves) In the future I intend to install solar energy, so I have to predict the weight of the s, right? That's why I'm going to put two 25 beams in these 5 meters.