The Sports Palace of Longarone is one of the most important multipurpose centres of Eastern Alps.

To make its new roofing NICLAS SRL of Cordignano (TV) chose ALUGRAF, a system of metal roofing conceived and manufactured by ALUBEL.

The Sports Palace of Longarone is a large multi-purpose structure fitted between the mountains of the upper Piave valley. With its two buildings, one of them with the swimming pool, it is one of the most important multipurpose centres of Eastern Alps.

Sports and cultural events as well as conferences are hosted, and it represents the strength with which mountain populations knew how to recover after the tragedy connected to the Vajont artificial lake.

Introducing such an imposing structure in such a wonderful and peculiar landscape, required a design engineering able to join the architectonic value of the plant, without altering the location, also taking into account the severe climate characteristics of the valley, with very cold winter temperatures and plentiful rainfall, as it usually happens in the Alps.

So for the roofing it was natural to choose a solution able to withstand such difficult conditions, choosing a material resistant to corrosion, able to drain easily excess of water and able to prevent its infiltration.

The old roofing, ribbed slabs in pre-painted zinc-plated steel, was no longer good for these tightness requirements. To replace it NICLAS srl of Cordignano (TV) used the metal roofing system for flat roofs ALUGRAF, studied and tested by ALUBEL (www.alubel.it) of Bagnolo in Piano (RE).

This is an ideal solution for roofing with large spans, also in case of slow slope pitch.

The metal slab, applicable without head junctions between the elements, in fact is equipped with a special "labyrinth" joint that guarantees total water tightness, once water is retrieved from the pitch.

The ALUGRAF system is composed of elements with modular width of three different measures: 400, 500 and 600 mm. The length of slabs instead is variable. They can be manufactured at the plant or directly on the construction site with a mobile profiling unit for coils.

This way the problem of shipment and handling of the most bulky elements is solved, otherwise for huge dimensions works the maximum dimension allowed for road transport could be even exceeded.

The slabs can even be made according to many kinds of materials, fitting any kind of design engineering needs. They are available in:

• raw and pre-painted aluminium (UNI 5754 alloy) in many colours;

• copper;

• stainless steel;

• zinc-titanium;

• pre-painted zinc-coated steel.

The slabs are installed with a special slot-in system with stirrups in polyamide, extremely resistant to tearing strain and to the abrasive effect of slabs movements, due to heat dilatations, equipped with a special profiling. Once the stirrups are installed on the structural support with screws, positioned in lines at modular distance, the fastening of the two adjacent elements is made with one slot-in junction (called "cappellotto").

The material chosen for the roofing of the Sports Palace of Longarone is aluminium UNI 5754, 7/10 thick, with great resistance to trail and corrosion, in antique copper colour Ral 6021.

Slabs were prepared directly on the construction site, in which pre-painted aluminium coils were transported.

The equipment necessary for the first step of the work includes reel, spacer wedge and profiling rolls mill with variable pitch, used to make slabs with different dimensions and the junction cappellotto. The largest slabs used in the work reached a length of 24 m.

The chosen width was 60 cm to make the great pitch surfaces, 40 cm for the coating of lowered pitch, delimited by protruding structural elements.

Both buildings feature four very large pitches, with double metal struts with box section located along the hips. There is a set of skylights positioned in a strip, around the top of the swimming pool building.

The other structure features pitches interrupted by an intermediate semi-continuous windows system. The lowered part of the roofing is divided into sectors by parallel metal elements exposed on the end. The structural system originally was made with a support in self-carrying corrugated sheets, connected with metal structures projecting with respect to the roof.

Once the top metal structures of the two buildings were renewed, cleaning rust signs and applying passivator products against corrosion and protecting them with new painting cycles, in order to apply the ALUGRAF system roofs were prepared installing wood joists, placed directly on the previous roofing. The joists were placed in transversal direction with respect to the slope with a pitch of 120 cm and fastened to the structure below with self-threading and self-piercing screws.

Among them, to guarantee a good degree of heat proofing, Foamglass heatproof panels were installed.

These are cellular glass panels, pre-coated on one side with a bituminous layer that acts as vapour barrier.

After taking all roofing elements to the top, with a 18 m spreader made available by NICLAS, the polyamide stirrups were fastened to wood joists, with two Torx screws with etching thread.

The special "Y" profiling of stirrups allows snap release, in the two transversal small channels, two contiguous elements, which are connected finally, with snap release again, with a separate upside down "U" connection joint: the so-called cappellotto.

The special profiling tightens the two continuous projecting parts on stirrups, without the need to seaming or piercing the slabs for installation. Easy and fast installation, this system guarantees to the slabs free movement concerning the variations due to thermal dilatation.