EP0323376B1 - Sealing roofing layer - Google Patents

Abstract

System for sealing roofing by means of two successive sealing layers, the first of which is mechanically fixed to the support and the second, self-adhering, is fixed to the first by cold self-bonding. <??>The first sealing layer is made by means of sealing sheets constituted by the assembly of a bitumen-based sheet reinforced with a strength member and of a film of a polymer having a high tear strength.

Description

The subject of the present invention is a method of producing a waterproofing for roofs according to the preamble of claim 1.

Various systems and methods known in general have been proposed to date for waterproofing roofs, among which one of the most commonly used consists of using a bituminous coating in two layers, the first of which is mechanically fixed to the support to be protected while the second is torch-welded to the first. However, such a system is not without drawbacks, welding with a torch requiring the use of very specialized labor and carrying certain obvious risks when the support to be protected is flammable.

In addition, the mechanical fixing of the first layer involves risks of perforation of the assembly by the screws or the rivets used, following the compaction of the support and / or the movements of the structure.

Another sealing system consists of apply directly to the support to be protected with a self-adhesive sealing sheet, the upper face of which is protected by a film of synthetic material, the adjacent sheets being joined either by partial covering, or by adding an additional strip to horse on both leaves.

However, the implementation of this type of self-adhesive material requires that the laying surface be regular, clean, without roughness or dust. Therefore, it is difficult to use this system on irregular supports such as thermal insulation or on old waterproofing coatings, in the case for example of a waterproofing repair.

On the other hand, due to the total adhesion, the sheets have to withstand the movements of the supports and therefore risk being quickly damaged.

Furthermore, in the event of the appearance of gas or water vapor between the support and the waterproof sheet as a result of moisture migration, there is a risk of creating overpressure zones of these gases and therefore of forming blistering which can lead to rupture of the sealing sheet.

Finally, in very windy regions, it is not always possible to obtain sufficient adhesion of the self-adhesive sheet on its support.

Document GB-A-2 080 196 also discloses a waterproofing for roofs, in accordance with the preamble of claim 1, comprising two superimposed layers, fixed to a support to be protected, the layers being constituted, on the one hand, by a first layer formed of bitumen-based sheets, reinforced by a reinforcement and covered at its upper face with a polymer film and, on the other hand, by a second layer formed of bitumen-based sheets comprising a self-adhesive underside -adhesive.

However, the sheets of the first layer mentioned in this document are fixed by self-adhesion to the support to be protected and therefore have the various drawbacks mentioned above.

Furthermore, document US-A-4 091 135 discloses a complex bituminous membrane, which can be applied by superposed layers on the roofs and comprising an essentially self-adhesive underside, having the various drawbacks mentioned above.

However, certain parts of said underside can be non-self-adhesive, but then require for their fixing a specific bituminous binder.

The object of the present invention is in particular to overcome the various aforementioned drawbacks.

To this end, it relates to a process for producing a waterproofing for roofs comprising two superposed layers, fixed to a support to be protected, the layers being constituted, on the one hand, by a first layer formed of sheets based on bitumen, reinforced by a reinforcement and covered at its upper face with a polymer film and, on the other hand, by a second layer formed of bitumen-based sheets comprising a self-adhesive underside, characterized in that it consists, first of all, of fixing on the support, exclusively mechanically, the edges of each sheet of the first layer resting on said support, covering each border of the first sheets of the first layer mechanically fixed on the support by a second sheet of the first layer adjacent to the first sheet and fixed on the latter by gluing along the covering edge and then covering the first layer by the second layer and then to fix by self-adhesion the second layer on the polymer film of said sheets of the first layer.

According to a first preferred characteristic of the invention, the bonding along the covering edge can be carried out by means of a cold glue.

In accordance with another preferred characteristic of the invention, the self-adhesive underside of the sheets of the second layer comprises a silicone protective sheet, removed before the fixing of the second layer to the first layer.

According to an additional characteristic of the invention, the upper face of the second layer is protected by a material chosen from the group formed by metal sheets, mineral granules and films of a synthetic material having a high chemical resistance.

The sheets of the first layer are constituted by the assembly of a bitumen-based sheet reinforced by a reinforcement and a film of a material having the double property of offering a high resistance to tearing and allowing a good adhesion of the self-adhesive sheet which constitutes the second layer of the sealing system according to the invention.

The bitumen-based sealing sheets used to produce the sheets of the first layer may be any sheet based on oxidized bitumen or modified bitumen reinforced by a reinforcement of mineral or organic fibers. They can thus be made of bitumen modified with an elastomer or with a thermoplastic polymer of the styrene-butadiene-styrene type, coating a frame such as a woven or non-woven sheet of glass, polyester, polypropylene or polyamide.

The film used to produce the sheets of the first layer must, as has already been said, have the dual property of offering great resistance to tearing and of allowing good adhesion of the self-adhesive sheet which constitutes the second layer of the sealing system according to the invention.

Such a film can be a film of a synthetic material such as polyethylene or propylene with a thickness of 10 to 200 micrometers and preferably 40 micrometers.

It can advantageously consist of a bi-stretched polyethylene film such as that sold by the firm VAN LEER under the name "VALERON®".

The sheets of the first layer are obtained by bonding such a film to a sealing sheet of known type, this bonding being carried out by means of an adhesive. suitable such as a solvent-based bituminous glue or a glue based on crosslinkable resin.

The sheets of the first layer have the particularly advantageous property of offering remarkable resistance to tearing, as well as excellent adhesiveness with respect to the self-adhesive sheets which constitute the second layer of the sealing system according to the invention.

It follows that the seal obtained according to the invention has the considerable advantage of double security due on the one hand to the implementation of two sealing layers, each of which is perfectly sealed by itself and of secondly to the perfect adhesion of the second layer to the first

The sheets used to produce the second layer of the seal are bitumen-based seal sheets comprising a self-adhesive underside protected by a detachable protective sheet, for example paper or silicone polypropylene. Their upper face can advantageously be protected either by flakes or mineral granules, or even by a metal foil or a film of a synthetic material having a high chemical resistance.

They may also include a reinforcement of mineral or organic fibers such as a woven or nonwoven web of glass, polyester, polypropylene or polyamide.

The implementation of the method according to the invention is carried out initially by dry unwinding on the support of the sheets of the first layer, which are fixed at the edge by mechanical fasteners such as screws, nails or rivets preferably provided distribution washers or plates. Each sheet is partially covered, on the mechanically fixed border, by the following sheet, which is fixed to it by gluing along the edge of recovery. This bonding can be carried out using a cold adhesive such as an adhesive based on bituminous binder or an adhesive based on reactive synthetic resins, for example an adhesive based on polyurethane or epoxy resin.

The second sealing layer is fixed to this first layer, in a second step, by simple unrolling and application of the self-adhesive sheets previously stripped of their silicone protective sheet, the joints between two adjacent sheets being produced by partial covering and obtained by simple self-adhesion.

In addition to the advantage already explained of double security, the seal obtained according to the invention offers the additional advantage of great ease of implementation since it does not require the use of welding with a torch, which at surplus eliminates the risks inherent in the presence of fire on a site.

The mechanical fixing of the first sealing layer also has the subsidiary advantage of allowing it to be placed on any support capable of accommodating screws or rivets, for example wood, wood-based panels. , metal or concrete, without this support having to meet the surface quality requirements required for the first sealing layers fixed by adhesive.

This mechanical fixing also offers the advantage, compared to bonding fasteners, of allowing gases or water vapor possibly present between the support and the first layer to be distributed regularly under this first layer, thus avoiding the phenomena of blistering.

• Liant : bitume élastomère styrène-butadiène-styrène
• Armature : fibres de verre d'un grammage de 50 g/m²
• Film de surface : feuille de polyéthylène d'épaisseur 40 micromètres
• Epaisseur nominale : 2 mm.

As an example of a sheet of the first layer, mention may be made of the one with the following composition and characteristics:

• Binder: styrene-butadiene-styrene elastomer bitumen
• Reinforcement: glass fibers with a grammage of 50 g / m²
• Surface film: 40 micrometer thick polyethylene sheet
• Nominal thickness: 2 mm.

Claims (4)

1. Process for producing a roof seal comprising two superimposed layers fixed to a substrate which is to be protected, the layers consisting, on the one hand, of a first layer formed by bitumen-based sheets reinforced by a reinforcement and covered in the region of its upper face with a polymeric film and, on the other hand, of a second layer formed by bitumen-based sheets comprising a self-adhesive under-face, characterised in that it involves firstly fixing on the substrate, in an exclusively mechanical manner, the edges of each sheet of the first layer resting on said substrate, covering each edge of the first sheets of the first layer mechanically fixed on the substrate with a second sheet of the first layer adjacent to the first sheet and fixed thereon by adhesion along the covering border and subsequently covering the first layer with the second layer then fixing the second layer onto the polymeric film of said sheets of the first layer by self-adhesion.
2. Process according to claim 1, characterised in that the adhesion along the covering border is brought about by means of a cold adhesive.
3. Process according to any one of claims 1 and 2, characterised in that the self-adhesive under-face of the sheets of the second layer comprises a silicone-containing protective sheet which is removed prior to the fixing of the second layer onto the first layer.
4. Process according to any one of claims 1 to 3, characterised in that the upper face of the second layer is protected by a material selected from the group comprising metallic foils, mineral granulates and films of a synthetic material having high resistance to chemicals.