The fiber cement sheet is an advanced construction product composed mainly of cement and, to a lesser extent, mineralized organic fibers and other organic compounds. The initial composition of the fiber cement contemplates the use of asbestos (asbestos) as reinforcement fiber, but for about thirty-five years this component has been replaced by cellulose, polystyrene, glass and synthetic vinyl fibers as a consequence of the relationship between asbestos and some health conditions.
According to some experts the composition of the fiber cement, combines the same principles of reinforced concrete considering that, instead of reinforcing steel fibers are used, the cement present in its composition acts as a hardening element, while gravel and sand confer it compression properties.
All the technology associated with its composition and manufacture give fibrocement endless advantages that make it a building material of inimitable characteristics for all applications associated with civil construction:
- Trabajabilid: Easy to cut, nail, drill and screw with conventional tools, fiber cement in general can be worked similar to a sheet of wood.
- Versatility: By fixing fasteners to supporting profiles, fiber cement sheets can be used as divisions or internal or external walls in combination with any type of construction. For the case of exterior surfaces or wet environments, the sheets have a waterproofing treatment applied during their manufacture, which makes them completely resistant to moisture.
- Resistance / Weight: In comparison with other alternative construction systems, fiber cement offers an optimum ratio of high resistance against very low weight. On impact resistance, fiber cement successfully covers all requirements, the degree of resistance being directly proportional to the thickness of the sheets.
- Durability: It is resistant to fire, moisture and impacts. It is not attacked by insects. The exterior surfaces of fiber cement offer a long life thanks to its high resistance to environmental elements: When coatings or paints are applied they considerably extend the useful life of the surfaces.
Fibrocement as application of roof bases
Due to its unparalleled properties and versatility, fiber cement offers a wide range of applications, this time we will be focused on the development of the application of roof bases, which aims to provide a basis for the final roof finish provided as a roof edification.
Using a conventional structural metal or wood base, provided with support belts with a maximum separation of 0.61 m, the sheets of fiber cement are fixed with special screws, this way this surface works as a base for the roof cover and, at its Once, it provides an impeccable finish like a ceiling on the inside of the construction.
According to the final finish of the roof cover and the appearance of the internal surface the roof bases can be classified as follows:
- Bases for asphalt tile: The fiber cement panels offer a level and stable surface that allows the correct application of an asphalt base layer on which the asphalt tile finish is applied according to the specifications recommended by the manufacturer.
- Bases for tile Creole: As in the previous case is recommended to apply a base asphalt blanket to proceed with the fixation of the Creole tile roof, in the case of using sheets of 12 mm, 14 mm or higher thickness , the fixation can be made directly on the sheets, when sheets with smaller thicknesses are used it is necessary to previously verify the permissible support capacities of the sheets.
- Base for fiber cement tiles: In the case of finishing the covering of the roof with fiber cement tiles, it is necessary to proceed as in the previous cases with the application of the asphalt blanket on the outer surface of the roof base and, additionally, provide a support structure (oriented transversely to the main structure) for fixing the tile panels, in order to avoid perforating the surface of the roof base and transmit the loads towards the main structure. The fixing of the tile panels must be done following the recommendations established by the manufacturer.
- Base for metal roofs: we proceed exactly as in the previous case including the surface structure for fixing the metal roof sheets selected.
- Base of exposed ceiling: One of the main characteristics of the sheets of fiber cement for the application of roof bases, is that the superficial finish of the visible face from the interior side of the building, offers an impeccable and aesthetic finish. Additionally, these panels have tongue-and-groove edges, thanks to which the finish of the joints is efficiently resolved. The finishes for this type of roof base can be smooth grooved surface, and grooved with wood grain texture. Roof base not exposed: Unlike the previous application, the internal face will not be visible from the inside of the building, having a suspended ceiling for it. The space between the internal surface of the ceiling base and the suspended ceiling is used for the passage of installations, wiring, pipes, etc.
For each one of the types of roof bases described above, a series of complementary products and elements must be available that ensure the formation of a roof of optimum quality.
The sheets of fiber cement must be supported on a support structure with maximum distance between axes of their components of 0.61 m, also it should be considered that the face of the support facing the meeting of two sheets must offer a minina surface of 44 mm. Structural components in galvanized steel or black steel: Profiles and / or hot or cold rolled beams of any geometry, used as structural support elements.
The minimum requirements of steel for this type of use are:
- Limit of creep 2400 Kg / cm2
- Minimum thickness of cold rolled profiles: 0.9 mm (20 gauge)
- In the case of galvanizing, a minimum coating equivalent to Z180 / G60 or equivalent to 180 gm / m2 (0.60 oz / ft2) must be guaranteed.
- For the use of black steel the application of coatings and / or as anticorrosive protectors is widely recommended.
The geometry, dimensions and thickness of the structure used must be determined by means of a structural study prepared by a professional.
In the case of using wood as a structural element and support, it must be selected structural quality, properly treated, dried and straight. The dimensions of the elements will be determined according to the previous structural study carried out by a professional.
The fixation of the structural elements of the roof base against the primary structure of the building, can be solved by the use of plastic dowels, screws, expansion bolts, nails, and other types of anchors, it should be noted the recommendation to use galvanized elements or with protection against corrosion, in order to guarantee a structure that lasts over time.
Fiber cement sheets:
The sheets of fiber cement recommended for the application of roof bases, are smooth grooved finish or texturized wood type, these offer an impeccable final finish of the work. However, it is also possible to use smooth Plystone sheets of 11 and 14 mm for the same type of application.
To a large extent, the good performance of the roof base system with fiber cement is due to the adequate fixing of the sheets to the supporting structure.
- In this sense it is essential to observe the following aspects: The fixing of the sheets is done with self-ailing screws type Wing placed every 0.61 m in the longest direction of the sheet. In the shortest sense, screws with washers should be placed in the manner of pisalaminas, except in the case of slotted sheets where screws without washers are used for the perimeters.
- For the fastening of the structural elements of cold profiles in galvanized steel, the use of galvanized screws # 8 x ½ “or ¾” self-drilling fine tip and drill bit for fixing structural elements with thicknesses from 0.8 mm to 1.4 mm is recommended; and galvanized screws # 12 x ½ “or ¾” self-drilling bit tip for fixing structural elements up to 2 mm thick.
- Sealers: For the sealing of the joints between sheets, it is recommended the application of elastic chemical sealants monocomponentes usually of polyurethane, with great capacity of elongation.
The application of fiber cement in the construction projects involves a great amount of economic advantages, minimizes the execution times of works, guarantees clean works of fast finishing and a minimum amount of debris. In H. Welle, S.A. We provide the most professional support and advice in their projects, we maintain the largest stock and ensure the continuity of supply for all your projects.