* * * * * The present invention relates to the field of building construction.

More in detail, the present inventon concerns a drainage system for finishing blocks for coverings, terraces, flat roofs or pavements and similar outside surfaces made watertight by means of waterproof sheathings or membranes.

At present, only a waterproofing membrane is placed on the covering floors or on outside pavements, usually made out of bituminous material. In particular, said membrane is placed at direct contact with the extrados of the structural floor, below the pavement or finishing block.

Said membrane, which is laid in strips and hot welded, is arranged for providing a watertight protection coating for the floor, preventing possible water seepages from damaging the structural parts of the buildings.

Said construction technology, however, is not able to prevent rain water from filtering through the finishing block of the pavement or of the covering, until reaching the waterproofing membrane. As the water can not flow away beneath said membrane, it accumulates and stagnates just between said waterproofing membrane and the finishing block.

Disadvantageously, said water stagnations cause the formation of moisture and condensation between the layers of material, which in turn cause the formation of unaesthetic mould stains.

The presence of water below the finishing block of pavements often causes the outcome of limescale in the joints of the tiles.

Even more disadvantageously, the stagnating water undergoes continuous freeze-thaw cycles due to the temperature range in the 24 hours of a day and in the following of the seasons.

Said freeze-thaw cycles may cause cracks, damages and breaks inside the materials' layers. Indeed, a sudden temperature decrease may cause the filtered water to become ice, increasing its volume and the rise of surface expansion forces operating on the concrete of the finishing block and onto the waterproofing membrane. Said expansion forces may lead to the formation of slits inside the material and even to the break and tear of the membrane itself, having a bad influence over time on the overall tightness of the waterproofing coat.

The present invention intends to overcome said limits, realizing a drainage system for making the water filtering through finishing blocks for coverings or outside pavements, made watertight by means of sheathings or membranes, to flow away.

It is also the purpose of the present invention to realize a drainage system easy to install and, at the same time, effective and cheap.

It is a further aim of the present invention to realize a drainage system also allowing a good ventilation of the floor and of the finishing block, avoiding the formation of moulds and condensation.

The aims set forth are reached by means of drainage system for a finishing block for coverings or outside pavements, made watertight by means of a waterproof membrane, characterized in that it comprises:

- a rusticated sheathing laid onto said waterproof membrane;

- a layer of non woven cloth placed onto said rusticated sheathing, wherein said rusticated sheathing is provided with holes arranged for allowing passage of the water filtering through said block towards said waterproof membrane, as well as said water flowing away into the hollow space between said rusticated sheathing and said waterproof membrane. According to a first preferred embodiment of the present invention, said drainage system comprises a perforated sheet made out of polyethylene or bituminized felt placed onto said rusticated sheathing.

Advantageously, said rusticated sheathing is made out of polyethylene or bituminous material.

According to a first aspect of the present invention, said rusticated sheathing and said layer of non woven cloth are permanently associated so as to form an indefinite strip.

According to a further aspect of the present invention, said rusticated sheathing, said non woven cloth layer and said perforated sheet are permanently associated so as to form an indefinite strip.

Advantageously, said indefinite strip has a first edge onto which the non woven cloth layer protrudes.

As an alternative, said indefinite strip has a first edge onto which the non woven cloth layer, coupled with said perforated sheet, protrudes.

According to a possible embodiment of the present invention, said indefinite strip has a second edge onto which the rusticated sheathing protrudes.

According to a further embodiment of the present invention, said indefinite strip has a head edge onto which the non woven cloth layer protrudes or, as an alternative, the non woven cloth layer coupled with the perforated sheet protrudes.

The present invention has many advantages.

Indeed, aside from solving the problem of the waterproofing of covering floors and of outside pavements, the system according to the present invention solves as well the problem of recovery, drainage and flowing away of the rain water filtering through the finishing block and usually stagnating on the waterproofing membrane.

Due to said rusticated ashlars, said membrane forms a hollow space divided into a number of interconnected channels which favour the downflow and diversion to runoff points for the water filtered through the block and through the non woven cloth layer, the perforated sheet and the holes provided on said membrane.

The non woven cloth layer filters the rain water but in the mean time it withholds the particles and the dusts of the concrete the finishing block is made of: this avoids that it encrusts and obstructs the hollow space between the rusticated sheathing and the waterproof membrane.

The perforated sheet has a filtering function as well, for separating the water from the particles or the dusts.

By a natural ventilation, said hollow space allows a quick spreading outwards of the moisture and the damp produced by the drained water accumulated in correspondence of the waterproofing membrane.

Furthermore, said hollow space also serves as a sound insulation means, due to the air layer obtained by means of the rusticated ashlars, which is optimal for dampening the diffusion of sound waves.

The drainage system according to the present invention is realized with multilayer material suitably realized for helping the installation thereof: in fact, each strip has at its edges at least one protruding layer, both for example the rusticated sheathing or the non woven cloth, so as to facilitate the superimposition of a plurality of parallel strips and assuring a sealing of the whole system.

Furthermore, each strip of material has a head edge as well, onto which the non woven cloth alone or coupled with the perforated sheet protrudes, for assuring the sealing of the whole system in longitudinal sense as well. The advantages of the present invention shall appear more clearly from the following description of preferred embodiments, made by way of an indicative and non-limiting example, with reference to the figures, wherein: Figure 1 shows a vertical section of a drainage system for finishing block for coverings or outside pavements, made watertight according to the present invention;

Figure 2 shows an axonometric view of an enlarged detail of the system according to figure 1 ;

Figures 3 and 4 show an axonometric view of the drainage system according to figure 1 during installation.

Relating to the figures, a drainage system 1 is shown for a finishing block

2 for coverings or outside pavements made watertight.

In fact, between said finishing block 2 and the coverings or pavement floor 8 a waterproofing membrane 3 is placed.

Said waterproofing membrane 3 is made out of a bituminous mixture enhanced with polymers that give the appropriate features.

Said system 1 mainly comprises a rusticated sheathing 4 directly laid onto said waterproof membrane 3, and a non woven cloth layer 5 interposed between said rusticated sheathing 4 and the finishing block 2.

Said rusticated sheathing 4 is made out of plastic material, like for example high density polyethylene, or out of bituminous material, and comprises protruding structures 9 with hemispheric ashlars or ashlars with truncated-cone shapes, arranged in an orderly manner on horizontal and vertical axes.

Said sheathing 4 is placed onto the waterproofing membrane 3 so that the rusticated ashlars 9 directly rest on the same. Said sheathing 4 is provided with holes 4' placed in correspondence with its plane and inclined parts so that their position may prevent the stagnation of water inside said sheathing.

Said holes 4' are arranged for allowing the filtered water to flow from said block 2 towards the waterproof membrane 3, and to flow away.

Said drainage system 1 comprises a perforated sheet 6, made out of polyethylene or bituminized felt, placed between said non woven cloth layer 5 and said rusticated sheathing 4.

Due to the rusticated sheathing 4, a hollow space S is thus obtained between said finishing block 2 and said covering floor or pavement; said hollow space is provided with interconnected drainage channels 10, arranged for conveying the rain water filtered through the finishing block 2 and the upper layers of the drainage system 1 - i.e. the non woven cloth 5 and the perforated sheet 6 - towards outflow points 11.

Said outflow points 11 comprise ducts placed along the circumference of the floor 8 and connected for reaching, by means of suitable inclination thereof, downpipes and/or ducts of the sewer system.

The same interconnected channels 10 for the water drainage may convey possible damp and moisture towards predetermined condensation outflows, realized by means of ventilation nozzles arranged on the circumference walls of the floor. In fact, the whole drainage system 1 may be turned upwards along said circumference walls, so that said ventilation nozzles are in connection with the hollow space S realized between the finishing block 2 and the waterproofing membrane 3 placed on said floor. Relating in particular to figures 3 and 4, said rusticated sheathing 4, said layer of non woven cloth 5 and said perforated sheet 6 are steadily associated to one another by hot welding, so as to realize one single strip with a head edge 7"'.

In particular, each strip 7 is specially shaped for facilitating the installation of the whole drainage system 1.

In fact, each strip 7 has an edge 7' and a head edge 7"' onto which the non woven cloth layer 5 coupled with the perforated sheet 6 protrudes, and it may advantageously also have an edge 7" onto which only the rusticated sheathing 4 protrudes.

With particular reference to figure 3, a first installation method of said system 1 according to the present invention is shown.

Said waterproofing membrane 3 is welded onto said covering or pavement floor 8.

Operatively, in the building site multilayer strips 7 are provided with an indefinite length, forming the real drainage system.

The strips 7 are placed side by side, so as to cover the whole surface of the floor 8, and are turned upwards along the vertical perimeter or the possible parapet walls.

The strips 7 are placed side by side so that the edge 7" onto which the rusticated sheathing 4 protrudes is in contact, and surmounted, by an edge T onto which the non woven cloth 5 coupled with the perforated sheet 6 protrudes, so as to guarantee at the same time the sealing of the system and the coplanarity of the installation plane, thus avoiding thickening of material in correspondence of the junction points.

With particular reference to figure 4, a second method of installation of the system 1 according to the present invention is shown.

In this case, the strips 7 have only a first edge T and a head edge 7"' onto which the non woven cloth layer 5 coupled with the perforated sheet 6 protrudes.

The strips are placed side by side, in transversal and longitudinal sense, so that each second edge 7" is surmounted by edges T onto which the non woven cloth 5 coupled with the perforated sheet 6 protrudes, and so that each end edge of said strips is surmounted by head edges 7"' onto which the non woven cloth 5 coupled with the perforated sheet 6 still protrudes.

The reduced thickness formed by the non woven cloth 5 coupled with the perforated sheet 6 creates no problem to the junctions, and possible differences are balanced by the finishing block 2.