Roofing Shingle

The present invention relates to a covering element, preferably for roofs, of the type commonly known as a shingle. In the publically accessible Norwegian application No. 75.2695, a particular type of covering element is described in which a plastic film covering an asphalt layer on the underside of the shingle is further coated with a release agent.

It is common practice that covering elements of the type described in Norwegian application No. 75.2695, as well as conventional shingle types in which the plastic film is not coated with a release agent, are shaped in such a manner that the shingle will to some degree simulate roofing slate or roofing tile when mounted on a roof. The conventional shingle can be of the general type described in U.S. Pat. No. 2,963,405 and a particularly preferred embodiment is a shingle provided with "tongues" such as illustrated in FIG. 6 of U.S. Pat. No. 2,863,405. However, since the known shingle types normally have a thickness in the range 3-4 mm, they will not provide the same relief effect which can be obtained by the normally thicker roofing tiles when laid on a roof.

The present invention provides a shingle type which has a thickness such that the laid shingle will better simulate a roofing tile and hence will give an enhancement relief effect.

In Danish patent specification No. 105,177, a bituminous roofing felt is claimed, the complete underside of which is covered with a layer of porous, particulated particles of fired clay. The purpose of the particulated material is to provide ventilation in order that trapped moisture, for instance from a concrete substrate, can be permitted to escape via the channels formed by the particulated material.

As mentioned above, an object of the instant invention is to provide a shingle type which, when laid, will exhibit an improved esthetic appearance by having an enhanced relief effect.

A further object of the present invention is to provide a shingle which has reduced elasticity or increased stiffness which facilitates the manufacture of the shingle and allows the shingle to be handled more easily during installation.

These objects are obtained by providing a layer of particulated light material on the underside surface of a shingle and providing a stiffening layer over the layer of particulated material. The particulated light material may be spheres of expanded polystyrene or a similar material having a diameter of at least 1 mm, preferably in the range of 1-6 mm. The stiffening layer may be a material selected from plastic film, paper, glassfiber tissue, felt or other similar material.

Further objects, advantages and features of the invention will become more fully apparent from a consideration of the constituent parts of the invention as set forth in the following specification taken together with the accompanying drawing.

In the drawing,

FIG. 1 is a bottom view of a preferred shingle in accordance with the present invention, a portion of the stiffening layer not shown so as to illustrate the layer of particulate material,

FIG. 2 is a top view of the shingle of FIG. 1, and

FIG. 3 is an enlarged cross-sectional view of the shingle of FIG. 1 taken along line 3--3.

Referring now to FIG. 1, there is shown a shingle 10 which is a preferred embodiment of the present invention. Shingle 10 includes a web 12 of felt, glassfiber tissue, or like material impregnated with asphalt or bitumen. Web 12 has a generally rectangular shape with one or more extending three-sided tongues 14. Covering the tongues 14 and a portion of the remainder of the web 12 is a layer of spheres 16 of expanded polystyrene.

The portions of web 12 not covered by layer of spheres 16 preferably have a coating of adhesive 18 which facilitates the retention of the shingle to a roof surface. The coating of adhesive 18 may further be covered with a peelable plastic film 20 which protects the adhesive prior to installation of shingle 10.

It is preferred that only the tongues 14 of shingle 10 and that portion of the shingle which is not in contact with the roof structure be covered with a monolayer of the spheres 16, i.e., only the part of the shingle which is overlappig the underlying layer of the adjacent shingles should be covered with the spheres. Such a construction facilitates the fixing of the shingle 10 to the roof structure. However, the entire bottom surface of shingle 10 could be provided with a monolayer of spheres 16.

Shingle 10 further includes stiffening layer 30 over layer of spheres 16 so that a "triplex" type shingle is formed comprising web 12, the layer of spheres and the stiffening layer. In FIG. 1, a portion of layer 30 has not been shown so that layer of spheres 16 may be illustrated. The material for stiffening layer 30 may be selected from plastic film, paper, glassfiber tissue, felt or other similar materials. The inclusion of stiffening layer 30 tends to reduce the elasticity of shingle 10 which thereby facilitates the cutting and packing operations in the manufacture of the shingles and also allows the shingle to be handled more easily when being laid on a roof or the like due to the increased stiffness of the shingle. The increased stiffness also will prevent the shingle from being blown up by when when laid.

Stiffening layer 30 may be attached to the layer of spheres 16 by applying an adhesive 28 to the layer of spheres and subsequently applying the stiffening layer to the adhesive. For example, web 12 of shingle 10 with layer of spheres 16 already applied may be brought into contact with an adhesive application roller so as to apply a suitable adhesive 28 such as melted asphalt onto the layer of spheres, and then applying stiffening layer 30 to the adhesive. In practice, it has been found advantageous to apply stiffening layer 30 to shingle 10 just before web 12 is cut to individual shingles. In this manner, the elasticity of shingle 10 can be utilized in the manufacturing process and the desired and advantageous stiffness provided by the addition of layer 30 may be utilized in the cutting operation and in the subsequent finishing, packaging and handling operations for the shingles.

FIG. 2 illustrates the top surface of the shingle 10 of FIG. 1. The surface of shingle 10 is provided with a pattern 22 for simulating roofing slate or roofing tile. In addition, the surface of shingle 10 has areas 24 which have an adhesive coating. The adhesive areas 24 help to secure and interlock the shingle to overlapping shingles when the shingle is installed on a roof.

FIG. 3 is a cross-sectional view of the shingle of FIG. 1 along line 3--3. The cross-sectional view is of course not drawn to scale in order to more clearly show the construction of shingle 10. Shingle 10 includes web 12 and the layer of spheres 16 on a portion of the one surface of the web. Over layer of spheres 16 is adhesive 28 joining the layer to stiffening layer 30. On the remaining portion of this surface of shingle 10 are adhesive coating 18 and optionally peelable plastic film 20. On the opposite surface of web 12 is an area of adhesive 24.

In addition to improving the esthetic appearance of the laid shingles, a layer of, for instance, expanded polystyrene spheres will also improve the insulating properties of the laid roof as shingles usually are laid with approximately 5 cm overlap. The improved insulation can be of importance in countries with cold winter climate. Furthermore, the monolayer of the expanded spheres will also reduce the noise caused by heavy rain. Thus, by providing shingles with a monolayer of spherical material such as expanded polystyrene with the above-mentioned diameter, it is possible to increase the "effective" thickness of a portion of the shingle without a significant increase in the weight of the shingle. The most effective relief effect is obtained when using dark colored spheres such as black spheres.

While there has been shown and described what is considered to be a preferred embodiment of the present invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention as defined in the appended claims.