AU2004210537B2 - Lightweight concrete roofing tile - Google Patents

Description

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT Applicant(s): RODERIC DE COSTA-SILVA Invention Title: LIGHTWEIGHT CONCRETE ROOFING TILE The following statement is a full description of this invention, including the best method of performing it known to me/us: 2 A ROOFING ELEMENT FIELD OF THE INVENTION The present invention relates to a roofing element, although it will be understood that the present invention may also be utilised as a cladding element.

BACKGROUND OF THE INVENTION Roofing elements or "tiles" are generally composed of a terracotta or cement material, which are heavy and reasonably brittle materials that are prone to breakage and are difficult to fit and secure.

SUMMARY OF THE INVENTION In a first aspect, the present invention provides a roofing element comprising a substantially symmetrical body, and at least one edge arranged to locate within a complimentary edge located on an other roofing element, the element being composed of an aerated cementitious composition.

The edge of the roofing element may be a half lap joint arranged to locate within a complimentary half lap joint located on the other roofing element.

The half lap joint may be arranged to, in use, receive a fixing material such as a cement mixture, to provide a sealable joint between the roofing element and the other roofing element.

The roofing element may be of a substantially rectangular shape.

3 The roofing element may further comprise a shoulder portion extending along a face of the element, wherein, in use, the shoulder portion assists in location of the element on a batten.

The roofing element may include at least one aperture arranged to receive fixing means to fix the element to a batten.

The apertures may be located such that, in use, the apertures are substantially covered by the other element, thereby providing a seal against the ingress of contaminants into the aperture.

In a second aspect the present invention provides a method of affixing roofing elements in accordance with the first aspect, comprising the steps of orienting a first roofing element with respect to a roof batten, fixing the first roofing element to the roof batten, orienting a second roofing element such that a half lap joint on the second roofing element substantially overlays a half lap joint on the first roofing element.

DETAILED DESCRIPTION OF THE DRAWINGS Notwithstanding any other forms which may fall within the scope of the present invention, an embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a perspective view of a roofing element in accordance with an embodiment of the present invention; Figure 2 is a side view along a section of the roofing element of Figure 1; Figure 3 is a side view along a section of the roofing element of Figure 1; -4 Figure 4 depicts the roofing element of Figure 1 in situ on a roof.

DESCRIPTION OF A SPECIFIC EMBODIMENT Referring to Figures 1, 2 and 3, there is shown a roofing element (in the present description referred to as a "tile") 10 in accordance with an embodiment of the present invention. The roofing tile 10 includes a substantially symmetrical body, which in a preferred embodiment, is rectangular in shape. The tile has two faces 12 and 14. However, it will be understood that the tile may be formed into any appropriate shape, such as a square shape, or any other symmetrical shape that assists the tile to locate with or mate with another complementary tile.

The roofing tile 10 further comprises at least one edge area 16, which in the present embodiment, is a half lap joint. The half lap joint 16 is shaped to receive an other half lap joint on another tile, so that a seal 16S (see Figure 4) may be formed between tiles when they are laid, in situ, on a roof. In a preferred embodiment, the half lap joint is provided along two opposing edges of the rectangular tile, although it will be understood that tiles may be manufactured with only one half lap joint edge (for example, tiles with only one half lap joint edge may be used along the edge of a roof, where the tiles are only required to mate with one other tile.

The seal formed between the tiles when two tiles are mated together may be strengthened by the addition of a cement or other sealing compound 18, which is applied between the half lap joints, as shown in Figure 3. The sealing compound may include a cement product, a silicon 5 (waterproof) sealant, or any other appropriate sealing material, which may be varied depending on local climatic conditions.

The roofing tile 10 may optionally include a shoulder 20 extending perpendicularly from a face of the roof tile The shoulder may be an addition to the roof tile (ie.

it may be a wooden, plastic, metal or other material that is attached to the roof tile using a glue, cement or screw fixture) or it may be pre-moulded or pre-cut (ie. the shoulder may be integrally formed with the tile).

The shoulder 20 allows the tile to be laid securely along a roof batten B (shown in Figure The shoulder serves the dual purpose of maintaining the tile in location whilst it is secured, and also serves to locate the tile in a correct orientation, thereby facilitating the efficient laying of tiles.

The roofing tile 10 may further include appropriate pre-drilled holes 22 arranged to receive screws or other fasteners (not shown in Figures 1-3) to secure the tile to the roof batten. The holes are preferably located in an area where they will be covered, in use, by another roofing tile. The covering of the holes by another tile preferably provides a secondary seal against the ingress of water or other contaminants into the roof area.

The roofing tile 10 is formed from an aerated cement product, which in a preferred embodiment, is an autoclaved aerated cement product which is marketed in Australia under the trade mark Hebel T M Hebel is an autoclaved aerated cement product which is lighter than conventional cement, yet retains many of the desirable properties of cement, such as durability, resistance to stress and resistance to other environmental factors. The Hebel cement product also provides desirable thermal and sound 6 insulation properties, and is easier to cut and shape than conventional cement products. In one embodiment, the tiles are cut and shaped from a block of Hebel material, although it will be understood that the tiles may also be pre-formed in an appropriate mould. It will be understood that whilst a preferred embodiment is formed from Hebel, any lightweight cementitious mixture may be utilised, such as cement mixtures which include plastic or other lightweight aggregate materials.

A method of affixing the roofing tiles 10 will now be described, with reference to Figure 4. A first roofing tile 40 is laid at one end of the battens on a roof, the shoulder of the tile 42 serving to correctly locate and orient the tile relative to the roof batten B. Once the tile has been correctly placed, the tile is then fixed to the roof batten using appropriate fasteners that may be installed through the preformed holes 44 located in the tile. Once the first tile has been laid, a second tile 46 may be positioned adjacent to the first tile 40, with the half lap joint of the second tile lining up with and overlapping with the half lap joint of the first tile.

In one embodiment, each half lap joint may be cut such that, when joined to another half lap joint, the resulting overlapping joints form a substantially impervious seal. Optionally, a thin coating of an appropriate fixing or sealing material, such as a cementitious mixture or a silicon sealant, is applied between the half lap joint on the first roofing tile and the half lap joint on the second roofing tile. In such a case, the tiles may be arranged such that when joined together, the half lap joints do not connect, but leave a suitable gap between the half lap joints to allow for the presence of the cementitious or sealant mixture.

7 Where the tiles are joined together at their half lap joints, the user may be required to tamp down the tiles to ensure an even spread of cement or sealant mixture.

Further tiles may subsequently be laid in the same manner as described above to complete a horizontal row of tiles.

Once the horizontal row of tiles has been completed, a further horizontal row of tiles may be secured in the same manner. In this case, a seal between successive horizontal rows of tiles may be achieved by providing a sealing mixture such as cementitious or silicon sealant along an edge of the face of one row of tiles (depicted by the number 24 in Figure 2 and by the thatched area 48 in Figure This provides a substantially impervious seal between adjacent tiles in each vertical row of tiles.

Once all tiles have been laid, a user may wish to apply any suitable coating, such as a polymer or plastic paint, a waterproof coating, or any other appropriate finish. Unlike conventional roofing tiles, which are generally glazed or otherwise coated prior to fitting, tiles in accordance with an embodiment of the present invention are only sealed after the roofing has been completed.

The present invention provides a number of advantages. Firstly, the roofing tiles, being made from an aerated autoclaved cement mixture, are lighter than conventional cement tiles, yet retain similar strength characteristics and superior temperature insulation and noise insulation properties when compared to conventional cement or terracotta tiles.

Secondly, the simple design of the tiles make them easy to install, whilst retaining an aesthetically pleasing quality.

-8- Thirdly, the tiles may be easily manufactured from Hebel T M blocks, or they may be preformed from a Hebel mixture. The particular shape of the tiles results in very little wastage when the tiles are cut from a block of Hebel. This reduces wastage of material.

Claims (8)

1. A roofing element comprising a substantially symmetrical body, and at least one half lap joint arranged to locate within a complimentary half lap joint located on the other roofing element wherein the roofing element is formed from an aerated cementitious composition.

2. A roofing element in accordance with claim 1, wherein the half lap joint is arranged to, in use, receive a fixing material such as a cement mixture, to provide a sealable joint between the roofing element and the other roofing element.

3. A roofing element in accordance with claim 2 or claim 3, wherein the roofing element is of a substantially rectangular shape.

4. A roofing element in accordance with any one of the preceding claims, further comprising a shoulder portion extending along a surface of the tile, wherein, in use, the shoulder portion assists in location of the tile on a batten.

A roofing element in accordance with any.one of the preceding claims, further comprising at least one aperture arranged to receive fixing means to fix the tile to a batten.

6. A roofing element in accordance with claim 5, wherein the apertures are located such that, in use, the aperture is substantially covered by other tile, thereby providing a seal against the ingress of contaminants into the aperture.

7. A roofing element as substantially described herein, with reference to the accompanying drawings.

8. A method of affixing roofing elements in accordance with any one of claim 1 to 7, comprising the steps of orienting a first roofing element with respect to a roof batten, fixing the first roofing element to the roof batten, and orienting a second roofing element such that a half lap joint on the second roofing element substantially overlays a half lap joint on the first roofing element.