GB2231346A - Roofing member with water-impervious membrane - Google Patents

Abstract

A roofing member in the form of a slate, tile or like generally flat rectangular member having at least one channel or groove on the normally lower surface (Fig 2) is characterised by the feature that a sheet of water impervious material 51 is located to extend over a portion of the normally lower surface of the member. <IMAGE>

Description

IMPROVED ROOFING MEMBER The present invention relates to an improved roofing member and is particularly intended as an improvement of the artificial slates or tiles (hereinafter referred to as "slates") as disclosed in our copending British Application No. 8819947.6 although is not intended to be exclusively restricted thereto and may be used with any roofing member having a channel or groove on the normally lower surface thereof.

Known "slates" with channels or ducts on their normally lower surface or "belly" may be subject to condensation on their lower surfaces which may drip or run onto the supporting battens and other surfaces and such do not provide any ventilation enhancing means nor any added insulation effect.

According to the present invention an improved roofing member in the form of a slate artificial slate, tile or like generally flat rectangular member having at least one channel or groove on the normally lower surface is characterised by the feature that a sheet of water impervious material is located to extend over a portion of the normally lower surface of the member.

Preferably the roofing member will have at least one ventilation/drainage groove or recess on the normally lower surface and preferably extending from a normally upper edge region to a normally lower edge region when the member is located in its normally inclined position of use and preferably said groove or recess runs into a groove or recess extending across the normally lower edge region of said member and preferably acting as capillary action limiting or prevention means which also facilitates ventilation as disclosed in copending Application No.

8819947.6.

The sheet of water impervious material (which we refer to as the "PDM" or Plastic Damp Membrane (or Member)) is preferably of plastics material, such as unplasticised PVC, although may be of any suitable material and preferably be flexible and preferably bonded to the belly of the slate at least at its edges by suitable adhesive (e.g. polymer based adhesive)or otherwise secured. Where ribs or the like are also provided on the belly, the sheet is preferably also bonded thereto. When plastics sheet is used such may be mirrored or silvered to increase the insulation effect.

The sheet will preferably extend over a major portion of the roofing member belly but preferably not over ventilation and/or drainage grooves or channels or channel portions at the bottom and possibly also at the top of the belly. The sheet may stop short of the nibs by a suitable amount e.g.|*" at least, to ensure the battens remain "fresh" and ventilated. The sheet will preferably be bonded to the lateral sides in the region of the lateral edges but not over the overlapping side regions provided with interlocking type slates. The sheet will preferably not extend over the "eves" of a slate.

The roofing member according to the invention has improved ventilation characteristics, prevents water dropping onto the supporting and underneath surfaces, provides an insulation effect, reduces condensation and in the event of a slate being cracked or broken, may act to prevent a leak through the crack.

In its broadest aspect where leak prevention is the primary purpose, the invention relates to a slate or tile having a water impervious sheet or membrane bonded thereto or embedded therein.

The invention will be described further, by way of example, with reference to the accompanying drawings, in which: Fig. 1 is a perspective view showing the normally underneath/lower surface or "belly" of a slate having a plastics material sheet or membrane bonded thereto; Fig. 2 is a plan of the slate of Fig. 1 showing the belly in full but with the sheet periphery indicated in broken line; and Fig. 3 is a section on the line X-X with the sheet thickness schematically illustrated on enlarged scale.

A preferred embodiment is illustrated in Figs.

1-3 and comprises a rectangular artificial slate or tile 20 of a rectangular standard shape and formed to have a substantially plain, normally upper surface 21 having an edge bevel in known manner and may possibly be provided with a surface appearance resembling that of a natural slate in known manner i.e have a riven texture on its face. The slate 20 as illustrated is the same as that illustrated in Figs. 7 to 9 of Application 8819947.6 except that a rectangular sheet 51 of flexible plastics material is bonded to the lateral edges 38 and portions 34-37 at least.

Figs. 1 and 2 show the normally lower side or "belly" of the slate 20 which has two projections or nibs 23 at the normally upper edge 24 of the belly. The nibs 23 have faces 23' remote from edge 24 and which are to abut a roof batten (not shown) for hanging of the slate in the manner as known with tiles. Faces 23' extend at right angles to the plane of the lower surface 25 of the slate 20 whilst the other side surfaces of the nibs 23 are inclined by being rounded as shown to provide increased strength with a top flat portion.

The belly of the slate can be regarded as having a number of surface portions lying in the same plane and having a number of recessed portions or portions of reduced thickness wherein the bases of the recessed portions lie in the same plane i.e. the reduced thickness portions are generally of the same thickness.

The belly 22 comprises a central rib 26 having a ventilation-drainage channel 27 therein leading from an upper region, where it terminates short of edge 24, to a generally circular recess 28 in a lower region. The main function of channel 27 is to drain the central region of the slate although it may also act to ventilate such. In a modified arrangement (not shown) the channel 27 may communicate with adjacent drainage-ventilation recesses to improve ventilation.

Two further ventilation-drainage channels 29, 30 are provided on the belly and lead, via generally circular recesses 31, 32, to a transverse channel or groove 33 near the normally lower edge and which in effect extends from a lower region of the recesses 28, 31, 32, which may be of any suitable shape and provide an enlargement in the channel and/or groove. The groove 33 which extends across the bottom of the slate 20 from edge region to edge region and through central recess 28. The groove 33 has its bottom surface on the same level as the bottom surface of the recesses 28, 31, 32. The groove 33 acts to prevent water being drawn up by capillary action with the surface of a slate beneath and this acts as a weather bar and also acts with the grooves 28, 31, 32 in the assistance of ventilation of the slate region therebelow when in its position of use.

Four spaced apart webs or deflection portions 34, 35 and 36, 37 extend inclinedly downwards from rib 26 preferably at an angle of 450 thereto and terminate at a distance from the surrounding rim 38 of the slate so as to form part of said channels 29, 30. The deflection portions 34 - 37 have their normally lower surface (the upper surface as viewed) in the same plane which is the same as the plane in which lie the rim 38 and the normally lower surface of rib 26. The deflection portions 34 -37 apart from providing strength to the slate, also act to deflect any condensed water outwardly to generally circular recesses 31, 32 and also facilitate circulation of air for ventilation purposes. The preferred disposition of deflection portions 34 - 37 at 450 provides a guide surface which facilitates cutting of the slates at 450 which is often required in roofing.

A further deflection and reinforcement portion 39 is provided on either side of rib 26 with walls preferably inclined at 450 and leads into walls 40 forming one side wall of groove 33. Portions 39 and walls 40 are in the same plane as the normally lower surface 18.

Recessed portions 41 - 46 are thus formed for the formation and/or collection of condensation and for ventilation purposes. Short ventilation-drainage grooves 47, 48 extend in the enlarged upper rim portion 18' from the end face 23' of the nibs 23 into the recessed portions 43, 44 respectively to facilitate ventilation and/or drainage of the rib region which is particularly prone to damage from damp. Two holes 49 are provided in the slate for securing nails (not shown).

The provision of the ventilation-drainage channels leading to the lower corner regions with halfbending of slates, results in any water drained from the underside of a slate being deposited on the centre of a lower slate rather than in the edge region.

Each of the deflection portions 34, 35, 36 and 37 preferably has two additional ventilation-drainage channels 50 extending therethrough and running parallel to channels 29 and dividing the deflection portions into equal segments. The additional channels 50 provide increased drainage and ventilation effect.

It is to be appreciated that various modifications and changes can be effected. For example, the number or shape or spacing of the deflection ribs may be changed as described. Furthermore, for larger slates, two or more main ribs (similar to 26) may be provided and the adjacent ends of the deflection ribs will be spaced to permit the drainage of water and ventilation. It is to be appreciated that whilst reference is made to a ventilation-drainage groove, such as shown in Fig. 2 is not a continuous groove as such but rather at least one drainage means or recess leading into lower recess forming the weather bar. Interlock connections may be provided in known manner to connect with adjacent slates.

As mentioned the substrate or sheet 51 is of flexible plastics material, such as unplasticised PVC, which is adhesively bonded (glued) to the surrounding rim 38 along the lateral sides and across the top and to the deflection portion 34-37,39 and rib 26 by an adhesive, such as a polymer based adhesive, over a major portion of the belly of the slate but leaving air ventilation passages (28,31, 32, 33) uncovered to permit adequate ventilation and drainage of these cavities 941-46) formed by sheet 51 on the belly of the slate. The sheet 51 terminates short of the nibs 23 (preferably buy|%") so as to leave the grooves 47, 48 partly uncovered and also to ensure the battens which are covered by such region remain "fresh".

The PDM sheet 51 (Plastic Damp Membrane) enhances ventilation of the cavities and additional protection of the underlying surfaces from condensation.

The sheet may be silvered and/of may be of any suitable material. In the event of cracking of a tile or slate 20, the sheet 51 acts to prevent water from leaking through the crack onto the surface below. Whilst the slate illustrated is of the non-interlocking type the concept (sheet) of the invention may be applied to slates or tiles with side interlocking arrangements in known manner.

Claims (14)

CLAIMS 0. A slate or tile having a water impervious sheet or membrane bonded thereto or embedded therein.

1. An improved roofing member in the form of a slate artificial slate, tile or like generally flat rectangular member having at least one channel or groove on the normally lower surface is characterised by the feature that a sheet of water impervious material is located to extend over a portion of the normally lower surface of the member.

2. A roofing member as claimed in claim 1 having at least one ventilation/drainage groove or recess on the normally lower surface.

3. A roofing member as claimed in claim 2, in which the groove or recess extend from a normally upper edge region to a normally lower edge region when the member is located in its normally inclined position of use.

4. A roofing member as claimed in claim 2 or 3, in which said groove or recess runs into a groove or recess extending across the normally lower edge region of said member and preferably acting as capillary action limiting or prevention means which also facilitates ventilation.

5. A roofing member as claimed in any of claims 1 to 4, in which the sheet of water impervious material is of plastics material, such as unplasticised PVC, although may be of any suitable material.

6. A roofing member as claimed in any of claims 1 to 4 in which the sheet material is flexible.

7. A roofing member as claimed in any of claims 1 to 6, in which the sheet material is bonded to the belly of the slate at least at its edges by suitable adhesive (e.g. polymer based adhesive) or otherwise secured.

8. A roofing member as claimed in claim 7, in which where ribs or the like are also provided on the belly, the sheet is also bonded thereto.

9. A roofing member as claimed in any of claims 5, 6, 7 or 8 in which, when plastics sheet is used such is mirrored or silvered to increase the insulation effect.

10. A roofing member as claimed in any of claims 1 to 9, in which the sheet extends over a major portion of the roofing member belly but not over ventilation and/or drainage grooves or channels or channel portions at the bottom and also at the top of the belly when provided.

11. A roofing member as claimed in any of claims 1 to 10 in which the sheet stops short of the nibs by a suitable amount to ensure the battens remain "fresh" and ventilated.

12. A roofing member as claimed in any of claims 1 to 11 in which the sheet is bonded to the lateral sides in the region of the lateral edges but not over the overlapping the side regions provided with interlocking type slates.

13. A roofing member as claimed in any of claims 1 to 12 in which the sheet does not extend over the "eves" of a slate.

14. An improved roofing member substantially as herein described with reference to the accompanying drawings.