Dimensions 40.5 x 24.1 cm
Gauge (approx) 34.3 cm
Pieces per sq. m 14.5
Unit weight 2.75 kg
Weight per sq. m 40 kg
Colours, dimensions and weight may slightly change due to the material characteristics
SOME IMPORTANT CONSTRUCTION RULES TO ENSURE THE CORRECT FUNCTIONING OF THE ROOF
It is essential that the tiles be ventilated on their lower surface Hence, the tiles are mounted on 4 x 4 cm section battens (usually made of wood), fixed parallel to the line of the eaves. Every 2-3 metres, the battens must be interrupted for a few centimetres in order to encourage the flow of air. The interruptions should be aligned. The distance between the centre of the battens is that declared by the manufacturer, but it is always better to check this on the ground before erecting. The first row of tiles should overhang the eaves to allow for the flow of water collected from the roof. In areas where there is snowfall, it is advisable to waterproof the surface below the first 3 or 4 rows of tiles. When it is necessary to secure the tiles because of high winds or a steep incline, mortar must never be used. Where necessary, they can be anchored using nails or screws through the hole in each tile. Another place where mortar is erroneously used is in the ridge of the roof. In fact the ridge should be fixed with special metal screws and the closure between the corrugated alignment of the tiles anc the straight edge of the ridges, is achieved by laying a special plastic band which prevents the infiltration of water but still permits the flow of air. Finally, in order to encourage the flow of air under the tiles, it is advisable to insert tile ventilators (these are special pieces that are the same size as a tile) during the construction of the roof in the ratio of approximaterly one per every 15/20 sq. m.
As a rule, a minimum incline of 30% should be used for Portoghese tiles and 35% for Marsigliese tiles. It is nevertheless appropriate to add a few other considerations. The incline necessary for the correct functioning of the roof depends on the lenght of the pitch (in the direction of the incline). The minimum values indicated refer to a pitch of normal lenght (5-5,5 metres). If the pitch is longer, the incline will be higher, whilst on the other hand, as an extreme example, a 25% incline would be sufficient for a 3-metre pitch. In any case, the lenght of a pitch that pours into the eaves must not be more than 10 metres. Should this happen, it is necessary to interrupt the pitch with a step, in order to create another collection point for the water. Of course, two parts thus obtained will require less incline than a single one. The mutual anchorage of the tile is sufficient to hold them in place up to an incline of 45-50%. With steeper inclines, the tiles should be fixed with a nail or a screw through the relevant hole. Another reason (aside from the incline) that may require tiles to be fixed is if the location is subject to strong winds.