POLYFAST – Fijación de crestas de plástico para claraboyas de madera
Debido al elevado Coeficiente de Expansión Térmica Lineal (CLTE) del policarbonato, 65~70 x 10-6 m/k, la tasa de expansión debida a los cambios térmicos debe tenerse en cuenta a la hora de calcular el tamaño necesario, y debe dejarse espacio suficiente para estos cambios durante la instalación.
Una lámina de policarbonato de 3 metros de largo, por ejemplo, se dilatará aproximadamente 2,1 mm por cada aumento de temperatura de 10 °C. Una plancha de 5 metros de largo sujeta en un extremo por estar pegada a una pared de ladrillos puede tener un movimiento en su extremo libre de más de 10 mm en el transcurso de un día con un aumento de temperatura de 30 °C.
Before the introduction of fasteners dedicated to fixing thermoplastics, and when metal fixing hex washer screws were still used, fixing any plastic sheets required at least 2 steps. First, pre-drilling an expansion hole that is approx. 2 times the diameter of the screw using a standard drill bit, which is followed by screwing down the metal roofing screw.
More often than not, builders will skip the first step and drill through the metal roofing screw directly, which is like a ticking time bomb waiting to explode, because sooner or later, the sheets are bound to deform, craze, crack, and break all the way through.
VULCAN Plastics, in collaboration with BDN Fasteners, have come up with PolyFast, a polycarbonate screw with a hassle free, fail safe design, and literally the easiest to use skylight fixing fastener on the market.
PolyFast Crest Fixing Fasteners can be used on all kinds of plastic glazing material and especially effective when used as polycarbonate roofing screws, with its length designed to accommodate the crest height of VULCAN ROMA and GRECA profiles.
The attached round cutting saw creates a much-required 10mm diameter thermal expansion hole on plastic roofing materials which then securely fastens onto the purlin underneath in one-go.
A large domed BAZ washer completes the package, covering the expansion hole while providing superior strength against high winds.
