Ventilated facade visible fixing solution
Ventilated facade visible fixing solution
The ventilated façade system with visible fastenings provides the “smartest” solution proposed by GammaStone. In fact it offers an extreme rapidity in the assembly, both of the substructure that of the panel itself, and thanks to the possibility of painting the rivets in the same color as the panel, the intrusion of metallic parts are minimized.
The resistance to mechanical loads acting on the facade is the second master point of the system with visible fastenings: thanks to the overlap surface offered by the head of the rivets, the strenght of the panel is also guaranteed for important loads.
The relative thermal expansion between the panel and the substructure is managed by appropriat
The system is composed exclusively by a vertical warping, which guarantees a faster assembly than other systems. In particular, vertical aluminum T profiles fixed to the outer wall of the building by adjustable brackets of two types are used: a structural type, 150 mm high, to be placed on the slab in correspondence of the floors, and the other intermediate, 80 mm high.
The first to bear the vertical load given by the weight of the facade and contrast the horizontal loads given by the pressure and depression of the wind, the second ones play the role of trolleys for the linear expansion of the materials, also contrasting horizontal loads.
Between the GammaStone AIR panel and the wall a panel of insulating material of both rigid and soft kind up to 140 mm in thickness may be positioned.
The length of the connection brackets must be chosen according to this dimension. The exterior GammaStone AIR panel is attached directly to the uprights by means of rivets from the outside. The plate may be perforated in work with specific tips.
Based on the static requirements and energy performance that the facade will need to meet, the number of posts, brackets and rivets will be sized.
The cavity for AIR ventilation formed between the insulating material and panel GammaStone AIR will also dimensioned in function of the thermofluid-dynamic calculations of the façade.
Ventilated façades with visible fastening grant a precise positioning of the panels with a joint of 5 mm between each other, and the minimal presence of metal fastening elements, painted in the same color of the panel, allows the aesthetic continuity of the ventilated façade with almost imperceptible intrusions.
The panels can be pre-drilled in the factory, or drilled on site with special tools.
Fixing is carried out from outside after leveling the panel. It is a good practice to always place a rivet in the middle of the panel to control its deformation and to ensure the relative movement due to thermal expansion of materials by sufficient tolerance between the hole and the diameter of the rivet.
In the horizontal section of the system stands the T shaped mullion, connected by self drilling screws to the bracket. The latter is equipped with a special cavity called “helping hand”, very helpful to obtain perfect vertical alignment. The thickness of the insulation, both rigid and soft, can vary up to a maximum of 270 mm, as well as the size of the ventilation space, whose amplitude is calculated as a function of the performance that the facade must guarantee. It is possible to interpose an isolator between the bracket and the masonry to interrupt the thermal bridge generated by the contact between the surfaces. In the section, the mechanical retention by the rivet with large head are clearly shown
In the vertical cross section, the different brackets can be easily seen. The main bracket, with structural use, is 150 mm high and it plays the role of a fix point for the linear dilatation control, in addition to being a joint for the mullions. Statically, this is a hinge. The smaller bracket, 80 mm high, statically works as a trolley and its allows the relative sliding between bracket and mullion. The gap between the brackets, and their number, must be calculated according to the system loads requirements.
This is one of the main points of the system. This is the principal AIR inlet of the façade, and, if the system is well designed from the technical and fluid dynamic point of view, the AIR from here goes up to the top of the façade with laminar motion. A grid or a pierced sheet, or an aluminum profile (included in our accessories range) must be placed to allow the external AIR to pass in the ventilation space according to the calculations.
The head detail ia another important point of the façade system. This is the outlet of the exhaust AIR coming up from the ventilation space and it must have two different roles: on the one hand, it has to protect the façade from the outside water thus granting the rain drainage, on the other hand, it has to allow the AIR outlet, without any AIR vortex or warm AIR stagnation.
The solution with visible fixing is not affected at all by the presence of the rivets, painted in the same color as the panels. The large panel size, up to 3x1 meters, ensures an effect of impact for every building constructed with the system GammaStone AIR. The panels are cut at 45 ° in the factory and can be fixed at each other with the appropriate brackets in the back stainless steel sheet to give the elements of the façade a "monolithic" appearance, ie without vertical escape. Otherwise, one can determine the architectural joint by project and maintain it during assembly. In both cases, thanks to the locking of the panels, the stability in time of the joint is fully guaranteed.
Another part to be designed in all detail. As in the case of the outer corner, the panels are fastened to each other to ensure the duration in time of the assembly and to confer the architectural aspect that most suits the designer, starting from a 0 mm joint.
The intrados side is a detail that gives personality to the building. In the version with visible fastenings made with GammaStone AIR panel, the edge at 45 ° is realized with extreme precision, and the panels fixed together by rear brackets. The final aspect is that of a monolithic block, solid and clean at the same time.
It is possible to realize the intrados with cut/bended plates in aluminum or other material, which mark more the presence windows. In this version, the technique involves a great accuracy in the realization of the plates, which must include the compensation profiles for expansions and manufacturing tolerances of the building. Even in this case, there are no visible rivets in the panel that constitutes the intrados.
The sill plays a fundamental role in the frame of the windows, since the role of rainwater drainage is delegated to this detail. The version in GammaStone AIR imparts a monolithic appearance to the final system, and ensures, thanks to the constructive system and seals, no infiltrations of water that can impregnate the insulation.
This declination of the sill, made with cut/bend aluminum sheet can be designed to ensure the evacuation of the ventilation AIR coming from the bottom, in addition to ensure the drainage of rainwater. The node must be designed so as not to allow water to enter from the outside, but at the same time to allow a convenient AIR expulsion.
The last component of the window external frame is the ceiling, which plays a decisive role, both from the architectural and fluid dynamic point of view. In addition to being a part of the window frame, is the other main entry point for the outside AIR. It is possible to achieve this effect even with the version made with panels GammaStone AIR.
The alternative version si the ceiling made of metal sheet, that has an important architectural impact on the building. To ensure proper functioning of the thermal/fluid dynamic machine that is a ventilated façade, the sheet must be perforated so as to allow the entrance of the external AIR in agreement with the calculations