GB2318595A

GB2318595A - Roofing slab for supporting cladding, e.g.tiles

Info

Publication number: GB2318595A
Application number: GB9622148A
Authority: GB
Inventors: Christopher Albert Hogben
Original assignee: Individual
Current assignee: Individual
Priority date: 1996-10-24
Filing date: 1996-10-24
Publication date: 1998-04-29
Anticipated expiration: 2016-10-24
Also published as: GB2318595B; GB9622148D0

Abstract

A thermally-insulating and waterproof slab (10) has means, e.g a castellated upper surface (20) to facilitate the fixing of cladding, e.g. tiles, thereto. The upper and lower areas (20 and 22) of the slab are preferably of glass-reinforced plastics, with a foamed core (34) of, e.g., foamed glass. The slab can be fixed to a roof framework by clips which slot into recesses (30) on the underside of the slab, and adjacent slabs are interconnected via holes (36). A central drainage channel (32) is also provided in the upper surface.

Description

IMPROVEMENTS IN AND RELATING TO ROOFING MATERIALS Field of the Invention The invention relates to a roofing slab suitable for use in roof construction. The roofing slab is suitable for use in a structural assembly comprising traditional timber roof structures, prefabricated frames and metal roof frames. A method of roofing construction using the roofing slab of the invention is also included within the scope of the invention.

Background to the Invention Coverings for domestic pitched roofs follow a long tradition, and despite the developments in new materials the older ones, such as slate and tiles and the ways of using them have not changed radically.

Most roofing materials for pitched roofs are laid across the roof in rows called courses so that the bottom edge of each overlaps the top of the one below. This means that they are laid working from the eaves up the slope of the roof to the ridge. Specially shaped tiles are used for capping the ridge or tips so as to weatherproof the junctions of the slopes. Where the covering meets a chimney or a wall it is protected with flashing, usually made of lead or mortar.

To comply with current building standards new and recovered pitched roofs must have a weather-resistant underlay of some kind fitted over the rafters. The purpose of the underlay is two fold, namely to reduce the effect of wind suction to the coverings and to provide a secondary barrier to prevent or reduce the ingress of moisture. This underlay, sometimes called sarking, is usually a reinforced bituminous felt or a suitable tear resistant plastic material. The underlay material is generally sold in rolls and cut to length as required.

The underlay sheet provides a barrier to any moisture that penetrates the outer covering of the roof. It also marginally improves the thermal insulation value of the roof, although to reach an insulation or thermal conductivity value (U) of 0.25 considerable additional thermal insulation must be inserted in the roofing structure. The current practice to achieve thermal insulation standards is to lay quilted or loose insulant fibres to the platform level of the roofspace (immediately above the ceiling joists).

Like the tiles themselves, the underlay is generally laid horizontally, working upwards from the eaves, each strip overlapped by the one above it.

The roof covering is supported on battens (usually of softwood) which are nailed across the rafters, over the underlay. The battens are usually pre-treated with a preservative to help prevent them rotting.

Most roof coverings are fixed to the roof by nails or clips, for example tiles generally have nibs that hook over the battens, keeping the tiles in place. Nails and clips may be used additionally to secure the tiles. The fixings are determined by the type and size of tile, the roof's pitch and the building's exposure.

In this general method of roofing construction, the three elements of underlay, thermal insulation and batten fixings are performed by three separate operations. This construction process takes considerable time. The underlay is often pierced or torn during construction.

It is an aim of a preferred embodiment of the present invention to overcome or obviate at least one problem encountered in relation to the prior art, whether referred to herein or otherwise.

Summary of the Invention According to the present invention in a first aspect there is provided a roofing slab comprising any two of the means adapted to receive roof covering materials or fixings for roof covering materials, waterproofing means and thermal insulation means.

The roofing slab therefore negates the need for the three separate components of thermal insulation, sarking felt and battens. The roofing slab can be laid directly on a roofing frame or the rafters of a roof and can provide dual functionality, thus making roof construction easier and less time consuming.

Suitably, the receiving means comprises a castellated surface on the roofing slab. The castellated surface provides alternating raised steps and recessed channels on the surface of the roofing slab. The castellated surface mimics the function and appearance of a plurality of roofing battens laid plane parallel.

Suitably, the raised steps of the roofing slab are adapted to receive nails or tacks. The nails or tacks are used to fix roof coverings such as slates or tiles to the roofing slab.

Suitably, the recessed channels of the roofing slab are adapted to accommodate the nibs of roof coverings.

Standard roof tiles have an overhang, termed a nib. The roofing slab is designed so that the nibs can overhang the recessed channels, thus holding the tiles in place.

Suitably, the waterproofing means comprises a layer of reinforced plastic. Preferably, the plastic is reinforced with glass. The waterproofing means stops any liquid which gets through the roof covering from entering the roof space. It also prevents the roofing slab from rotting.

Suitably, the thermal insulation means is noncombustible. The thermal insulation means is preferably in the core of the roofing slab. Suitably, the roofing slab provides a minimum 0.25 U value.

Preferably, the roofing slab provides receiving means, waterproofing means and thermal insulating means.

The roofing slab combining the three elements of sarking felt, batten fixings and insulation into a single component negates the need for separate layers of sarking felt, insulation and battens. The roofing slab can be affixed directly to a roof frame or rafters and then roofing tiles or slates, for example, affixed directly to the roofing slab. In using the roofing slab the construction process is made considerably easier and less time consuming.

Suitably, the roofing slab comprises a drainage channel. Preferably, the drainage channel runs the full width of the slab, substantially perpendicular to the direction of the castellations. Preferably, the drainage channel only extends up to one quarter of the way through the roofing slab, from the castellated surface. The drainage channel provides for drainage of the recessed channels of the castellated roofing slab to prevent water build-up.

Suitably, the roofing slab further comprises one or more regions adapted to receive fittings for securing the roofing slab to the roof frame. These regions allow for fitting of clips, for example, to the roofing slab, which then can be screwed or nailed to the rafters of timber roofing systems or fastened to a metal roofing system.

The clips negate the need to drill into the roofing slab and makes construction of the roof easier and less time consuming, and allows the fastening of the slabs to the roof frame to be undertaken from beneath the slab level.

Suitably, the roofing slab further comprises predrilled holes along its edges. Such holes act to allow fixing of the roofing slabs to each other and for fixing the slab to metal or timber roof frames. Slabs adjacent to each other may be strapped, utilizing these pre-drilled holes, by high tensile heavy duty strapping.

Suitably, the roofing slabs are further connected to a guttering means. Such guttering is connected to the roofing slabs at the eaves of a roof. The drainage channel therefore allows any liquid to drain directly into the guttering.

According to the present invention in a second aspect there is provided a structural assembly comprising a plurality of adjoining roofing slabs according to the first aspect of the invention affixed to a roofing frame.

Suitably, the roofing slabs are affixed to the roofing frame by clips which slot into the roofing slab and are nailed or clipped to the roofing frame. Suitably, the roofing slabs are joined by connecting means, utilising the pre-drilled holes in the roofing slabs.

Suitably, the drainage channel extends along the plurality of adjoining roofing slabs. Suitably, the castellations on each castellated roofing slab extend along the plurality of roofing slabs.

The roofing slabs are designed to extend over the whole of a roofing system. When two or more roofing slabs are laid side by side, either the ridges of the castellated surface, or the central channel should be continuous. To allow the drainage channel to extend from slab to slab, the roofing slab is adapted to receive a channel clip, which extends from the drainage channel of one roofing slab to the drainage channel of a second roofing slab. Suitably, when in use, the drainage channel drains the roofing slab down to the eaves of a roof construction.

According to the present invention in a third aspect there is a method of roof construction comprising: (a) affixing a plurality of roofing slabs according to the first aspect of the invention to a roofing frame; and (b) affixing roof coverings to the roofing slabs.

Each roofing slab is capable of being cut to size and shape as necessary on site, using conventional hand saws or electric saws. Therefore, the whole of a roof frame can be waterproofed and insulated using a number of the slabs. The roofing slabs are strong enough to hold the weight of a person, during both the course of the roof construction and its future maintenance.

Suitably, roofing slab has a standard size of 1800 mm x 600 mm x depth 126 mm, including castellations. The depth of the roofing slab may vary, depending upon the thickness necessary to obtain a thermal conductivity 'U' value of less than 0.25.

Brief Description of the Drawings The invention will now be described, by way of example only, with reference to the drawings that follow; in which: Figure 1 shows a side view of a roofing slab according to an embodiment of the first aspect of the invention.

Figure 2 is a cross section through the roofing slab shown in Figure 1.

Figure 3 is a plan view of the roofing slab shown in Figures 1 and 2.

Description of Preferred Embodiments Referring to Figures 1 to 3 of the drawings that follow there is shown a generally planar and rectangular roofing slab 10, with four sides, 12 opposite 14, 16 opposite 18, an upper surface 20 and an underside 22.

The upper surface 20 is castellated, that is, it is toothed and alternates between an upper level 24 and a lower level 26. As can be seen from Figure 3 the castellated upper surface 20 extends for the whole length of the upper surface 20, from side 16 to side 18, with the castellations running parallel to sides 12 and 14. The overall effect is to provide ridges 28 on the upper surface 20 of the roofing slab 10 which mimic the appearance of a plurality of roofing battens laid plane parallel.

Referring to Figure 1, the underside 22 of the roofing slab 10 is shown as having two recessed undercut regions 30 at its edge each in the form of a collared slot. The recessed regions 30 are adapted to slideably receive plates (not shown) which can be used to attach the roofing slab 10 to a roof frame or rafters. The recessed regions 30 in the underside 22 are on the edge of sides 16 and 18 at about one quarter and three quarters of the way along the length of the roofing slab 10, as this is where the roofing slab 10 is to be fixed to a roofing frame.

Referring to Figures 2 and 3, the roofing slab 10 is shown as having a central channel 32 which extends from side 12 to side 14 of the roofing slab 10, perpendicular to the direction of the ridges 28. The channel 32 comprises a U-shaped recess on the upper surface 20 of the roofing slab 10, extending from the lower surface 26 of the castellations extending about one quarter of the way through the roofing slab 10.

Figure 3 shows six holes 36, pre-drilled through the slab. The holes 36 are present so that they can receive a staple-like slab joiner or strapping so that roofing slabs 10 can be joined together (joining side 18 of a first slab to side 16 of a second slab), to further roofing components or to rafters or joists.

The upper surface 20 and underside 22 of the roofing slab 10 are made of a rigid glass reinforced plastic which provides a waterproof layer. The roofing slab 10 has a core 34 comprising an insulating material such as foamed glass or Phenolic foam. The slab 10 is designed to be flame proof, waterproof and strong. The slab is made in a standard size of 1800 mm x 600 mm x depth 126 mm, including the castellations. It should be appreciated that other sizes of roofing slab will also be suitable.

The slab is suitable for being cut to size as necessary on a construction site, using conventional hand saws or electric saws. Also, as the slab 10 is made of lightweight materials it is suitable for being carried and fitted by two operatives.

The roofing slab 10 will now be described as it would be used in roof construction to provide a one piece slab providing the functions of waterproofing, insulation and fixing means for traditional roof coverings such as tiles and slates, on metal or timber roof frames.

The roofing slab 10 can be affixed to a roofing frame (not shown) via clips (not shown) which slot into the recessed regions 30 on the underside 22 of the roofing slab 10. The clips can be nailed to the rafters of timber roofing frames or clipped onto metal roofing frames. The roofing slabs 10 are laid flat on the roofing frame and extend to cover the whole roofing frame. The roofing slab 10 can be cut to accommodate all sizes of roofing frame.

The roofing slabs 10 are laid such that side 18 of one slab 10 is next to side 16 of a second slab 10, with the slabs 10 being joined together by heavy duty strapping or staple-like clips joining the pre-drilled holes 36 of one slab 10 with those of an adjacent slab 10. When correctly assembled, the ridges 28 on consecutive roofing slabs 10 should extend from side 16 of the first roofing slab to side 18 of the last roofing slab 10 in a run.

Also the slabs 10 are fitted together such that the drainage channel 32 extends from side 12 of one slab 10 to side 14 of the last slab 10 in a run. To aid the continuation between the channels 32 of adjacent slabs 10, a channel clip can be used (not shown).

When the roofing slabs 10 have been attached to the roofing frame, the roofing frame is insulated and waterproofed. The castellated upper surface 20 of the roofing slab 10 provides batten-like fixing points for the tiles or slates of a roof covering. The tiles or slates can be fixed to the roofing slab 10 by means of nails or tacks, which pass through the roof covering and into the raised steps 24 of the roofing slab 10. Alternatively, nibs which overhang the end of tiles can overlap the ridge 28 formed between a raised step 24 and a recessed channel 26 to provide for fixing of the roof covering to the roofing slab 10 without the need for nails or tacks.

The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

Claims:

1. A roofing slab comprising any two of the following: receiving means adapted to receive roof covering materials or fixings for roof covering materials, waterproofing means and thermal insulation means.

2. A roofing slab according to Claim 1, in which the receiving means comprises a castellated surface on the roofing slab, the castellated surface providing alternating raised steps and recessed channels on the surface of the roofing slab.

3. A roofing slab according to Claim 2, in which the raised steps of the roofing slab are adapted to receive nails or tacks.

4. A roofing slab according to Claim 2, in which the recessed channels of the roofing slab are adapted to accommodate the nibs of roof coverings.

5. A roofing slab according to Claim 1, in which the waterproofing means comprises a layer of reinforced plastic.

6. A roofing slab according to Claim 5, in which the plastic is reinforced with glass.

7. A roofing slab according to Claim 1, in which the thermal insulation means is non-combustible.

8. A roofing slab according to Claim 1, in which thermal insulation means is in the core of the roofing slab.

9. A roofing slab according to Claim 1, in which the roofing slab provides a minimum 0.25 U value.

10. A roofing slab according to Claim 1, in which the roofing slab provides receiving means, waterproofing means and thermal insulating means.

11. A roofing slab according to Claim 2, in which the roofing slab further comprises a drainage channel.

12. A roofing slab according to Claim 11, in which the drainage channel runs the full width of the slab, substantially perpendicular to the direction of the castellations.

13. A roofing slab according to Claim 11, in which the drainage channel only extends up to one quarter of the way through the roofing slab, from the castellated surface.

14. A roofing slab according to any preceding claim, in which the roofing slab further comprises one or more regions adapted to receive fittings for securing the roofing slab to the roof frame.

15. A roofing slab according to any preceding claim, in which the roofing slab further comprises pre-drilled holes along its edges.

16. A roofing slab according to any preceding claim, in which the roofing slab is further connected to a guttering means.

17. A structural assembly comprising a plurality of adjoining roofing slabs according to any preceding claim affixed to a roofing frame.

18. A structural assembly according to Claim 17, in which the roofing slabs are affixed to the roofing frame by clips which slot into the roofing slab and are nailed or clipped to the roofing frame.

19. A structural assembly according to Claim 17, in which the roofing slabs are joined by connecting means, utilising pre-drilled holes in the roofing slabs.

20. A structural assembly according to Claim 17, in which a drainage channel extends along the plurality of adjoining roofing slabs.

21. A method of roof construction comprising: (a) affixing a plurality of roofing slabs according to Claim 1 to a roofing frame; and (b) affixing roof coverings to the roofing slabs.

22. A roofing slab substantially as hereinbefore described, with reference to and as shown in the accompanying drawings.