Slate retaining device and method of retaining a slate on a structure

Abstract

The slate retaining device 10 comprises an elongate member 20 having a first end 21 and a second end 22. The first end of the elongate member comprises a securing portion 30 for securing the device to

Description

The present invention relates to a slate retaining device and a method of retaining a slate on a structure. The present invention finds use, for example, in methods for replacing missing or damaged slates on a roof, without removing, disturbing, or damaging adjacent overlying or underlying slates. The present invention also relates to a kit comprising a slate retaining device and a tool for use in methods of retaining a slate on a structure. It should be noted that throughout this specification, reference is made to a ‘slate’ or to ‘slates’. However, it is to be understood that devices, methods, and kits embodying the present invention are equally applicable to roofs clad in other stones, artificial slate, tiles, shingles or the like. In the interests of clarity and brevity, the term ‘slate’, as used in this specification, is to be interpreted broadly to cover all cladding materials which are installed in a similar manner to a slate. It should also be noted that the devices, methods, and kits embodying the present invention are not restricted to use on roof structures, and may be employed to retain slates on other structures including, but not limited to, vertical walls, fences, shelters, or any structure clad functionally or decoratively in slates or similar materials. In the interests of clarity and brevity, the term ‘roof’, when used in this specification, is to be interpreted broadly to cover all surfaces and structures clad in slates or the like. Slate roofs protect the interior of buildings and other structures from the elements. The slates are generally supported by a frame, for example a timber structure. The frame is typically formed from a series of generally horizontal battens affixed to pitched rafters. Each slate is secured to an underlying batten using one or more fixings such as nails which extend through corresponding holes in the slate. Typically these fixings are made of metals, such as steel or copper. The slates are arranged in overlapping rows such that the fixing(s) and hole(s) used to secure each slate to the roof are covered by the overlying slates of the row above to prevent the ingress of water. Over time, the slates on a roof are subject to wear and tear. Unavoidable wear is caused by exposure to the elements, for example rain, wind, frost and sunlight. Wear or damage might also occur due to impact from falling branches, snow and ice, or accidental damage while performing maintenance work on the roof. This wear and tear can ultimately lead some slates, particularly those with minor defects at the point of installation, to crack or break. In some instances, a damaged slate may break away from its fixing and slide from the roof, leaving a large gap in the roof. In other instances, the slate fixing itself may break, causing the slate to become dislodged or fall from the roof. This may occur, for example, where the fixing is made of a metal which degrades or corrodes over time, or where the fixing is subject to a large force, such as an impact, causing it to shear. This damage can be detrimental to the integrity of the roof and may result in the ingress of water. Water can then leak into the underlying structure or building where it can cause serious damage. Such damage can be difficult and costly to rectify. It is therefore necessary to repair the roof by replacing damaged slates at the earliest opportunity. It is often the case that only one or a small number of isolated slates are damaged or missing in an otherwise sound roof. It is therefore often necessary to replace only a single or a small number of damaged or missing slates without replacing, removing, disturbing, or damaging overlying and underlying slates of adjacent rows of slates. Replacing a single or small number of slates in a roof is, however, a challenging task. As discussed above, each fixing used to hold a slate in place is typically covered and rendered inaccessible by overlying slates. Slate removal is therefore performed by sliding a tool, such as a slate ripper or slate removal saw, under the slate to be removed to engage with each fixing, so that the fixing(s) can be cut or pulled free from the underlying batten. The slate to be replaced can then be removed by sliding it down the pitch of the roof from between the overlying and underlying adjacent slates. However, once the fixing and the slate to be replaced have been removed, the old fixing point on the underlying batten still cannot be accessed without removing the overlying slates. Therefore, in order to secure a replacement slate to the roof, without removing or disturbing the overlying slates, an alternative fixing is required. Commonly, a slate hook is used to retain a slate on a roof structure. Slate hooks generally comprise a rigid elongate rod, typically of metal. A first end of the rod is typically bent and pointed to form a fixing or spike that may be driven into a roof batten. A second end of the elongate rod is shaped to define a hook, within which a bottom edge of a replacement slate can rest. In use, the fixing at the first end of the slate hook is driven between the underlying slates, into the batten to which the underlying slates are affixed, so that the elongate rod extends down the pitch of the roof, with the hook at the second end of the rod protruding upwards. The slate to be fitted is then manoeuvred so that the lower edge of the slate comes to rest within, and is retained and supported by, the hook at the second end of the elongate rod. Examples of known slate hooks are disclosed in United States published patent applications US481724A and US646623A. However, traditional slate hooks suffer from a number of drawbacks. Firstly, slate hooks, being rigid, have a fixed length and can only be used to support slates where the separation between the battens of the underlying roof structure falls within a standard range. If the separation between adjacent battens falls outside a standard range, the slate hook will not support the slate at the correct height (i.e. in line with adjacent slates in the same row). Therefore, a roofer must carry a range of slate hooks of different lengths, particularly in cases where the construction of the underlying roof structure is not known, or where the battens have an irregular spacing. Secondly, installation of replacement slates cannot be carried out using a slate hook. In particular, the protruding hook obstructs the passage of the replacement slate and prevents it being slid between the overlying and underlying slates in adjacent rows. Applying a force to manoeuvre the replacement slate in this manner will damage or dislodge the overlying and underlying slates, and / or damage the replacement slate itself. To replace a slate on a pre-existing roof, more rudimentary devices known as a ‘straps’ or ‘tingles’ are used . A tingle comprises a flattened flexible elongate strip, typically of metal such as copper or lead, having a first end and a second end, with a through hole formed at or near the first end. In use, the tingle is positioned so that it lies flat over the gap between the underlying slates. A fixing, such as a nail, is then driven through the hole at or near the first end of the tingle, between the underlying slates, and into the batten to which the underlying slates are affixed. The tingle extends down the pitch of the roof from the first end to the second end. A replacement slate is then slid upwards between the underlying and overlying slates until it is clear of the second end of the tingle. The second end of the tingle is then folded to wrap around, support, and retain the lower edge of the replacement slate at the desired height. Tingles therefore provide more flexibility than slate hooks, as they can be used to retain slates at any desired height and do not obstruct the replacement slate as it is manoeuvred into position. However, while tingles overcome the drawbacks of slate hooks, they also suffer from disadvantages. Firstly, roofers must always purchase and carry nails in addition to tingles, which makes them more costly than slate hooks, and requires roofers to carry additional inventory. Secondly, as tingles are made from comparatively wide strips of metal, the portion of the tingle that is folded over the bottom edge of a replacement slate remains visible, even from the ground. This is unsightly and can detract from the appearance of a roof, especially when the tingle is formed from an easily visible metal, such as copper. Finally, tingles, being made from flexible strips of metal are less robust than rigid slate hooks, and more likely to fail over time. Consequently, tingles do not retain slates as securely as slate hooks. This is particularly the case with tingles formed from lead, which is a soft metal and results in the tingle being prone to being bent and releasing the slate it is holding. Attempts have been made to overcome the disadvantages of both traditional slate hooks and tingles. For example, United Kingdom patent no. GB2473637B discloses a singlepiece slate retainer including a first portion that is securable to a target area of a roof, and a second portion for holding a slate in position on a roof relative to the first portion. The first portion and second portion are separated by an integral middle portion. The middle portion is resilient so that the second portion is resiliently flexible relative to the first portion so that, in use, the second portion is flexible between two underlying slates. Because the second portion flexes downwardly between the two underlying slates, the second portion does not interfere with the replacement slate. 10 07 23 Once the replacement slate is in position, the second portion can flex back in order to retain the replacement slate in position relative to the target area using the second portion of the slate retainer. However, the slate retainer is complex and costly to produce and, due to the resilient nature of the middle portion, does not retain slates as securely as traditional rigid slate hooks. For example, the resilient middle portion may flex after installation causing the slate to shift or move out of line. The second portion may even flex downwardly between the underlying slates after installation, for example if pushed by debris such as snow or ice, causing the replacement slate to fall from the roof. Falling slates present a significant safety hazard. Therefore, there remains a need for a slate retaining device which overcomes the disadvantages of existing slate hooks and tingles. In particular, there remains a need for a slate retaining device that does not obstruct a replacement slate as it is manoeuvred into position but nevertheless retains the slate securely once it has been correctly located. It would also be beneficial to provide a device that can retain slates at the correct height regardless of the separation between the battens of the underlying roof structure, is cheap to produce, and does not detract from the appearance of a roof. According to a first aspect of the present invention, there is provided a slate retaining device for use in replacing a slate on a roof structure between underlying and overlying rows of slates comprising: an elongate member having a first end and a second end; wherein the first end of the elongate member comprises a securing portion, for securing the slate retaining device to a structure; and wherein the elongate member comprises a plastically deformable portion adjacent the second end having at least one weakened region spaced apart from the second end to facilitate plastic deformation of the elongate member. The slate retaining device comprises an elongate member. The elongate member may be formed from any suitable material, including but not limited to metals, plastics, or combinations thereof. Preferably, the elongate member is formed from a metal, for example copper, steel, iron, or aluminium. Preferably, the slate retaining device is formed as a single component. In some embodiments, the elongate member is a rod, for example a rod having a circular cross-section. Other shapes for the cross-section of the rod may also be used. The first end of the elongate member comprises a securing portion. The securing portion may include any suitable means for securing the slate retaining device to a structure, such as a roof batten. In some embodiments, the securing portion may comprise an opening, such as an eyelet or a slot. In use, a fixing, such as a nail or screw, may be driven through the opening and into an underlying structure, such as a roof batten, to secure the slate retaining device to the structure. However, in preferred embodiments, the securing portion comprises a spike. The spike is preferably formed integrally with the elongate member. The spike may extend from the first end of the elongate member at an angle, for example an acute angle. In use, the spike may be driven into an underlying structure, such as a roof batten, to secure the slate retaining device to the structure. In some embodiments, the spike may be threaded. The provision of a spike in the securing portion of the elongate member eliminates the need to provide additional fixings such as nails or screws in order to secure the slate retaining device to a structure. The slate retaining device comprises a plastically deformable portion adjacent the second end of the elongate member. The plastically deformable portion includes at least one weakened region spaced apart from the second end of the elongate member to facilitate plastic deformation of the elongate member, for example when the elongate member is subjected to a force. The at least one weakened region may be formed by any suitable means, provided the or each weakened region has a lower resistance to plastic deformation than the remainder of the plastically deformable portion of the elongate member. In one embodiment, the or each weakened region is provided by a portion of the elongate member having a reduced diameter. For example, the at least one weakened region may comprise an indent formed in the surface of the plastically deformable portion of the elongate member. An indent may be formed in the elongate member by cutting or stamping a surface of the elongate member. The presence of an indent weakens the elongate member in the region of the indent. When a force is applied to the elongate member, the weakened region will deform more readily than the remainder of the plastically deformable portion. Thus, plastic deformation of the elongate member is facilitated by the presence of an indent. Additionally or alternatively, the at least one weakened region may comprise a flattened region of the elongate member, such as a crimp. The flattened region may be formed by pressing or stamping. Flattening a region of the elongate member will facilitate plastic deformation of the elongate member within the flattened region, in at least one dimension. Additionally or alternatively, the at least one weakened region of the elongate member may comprise a region having a reduced thickness, such as a recess or groove of a reduced diameter formed circumferentially around a portion of the elongate member. By way of example, the thickness of the elongate member may be reduced by machining, or by stretching a portion of the elongate member. Reducing the thickness of the elongate member will cause a weakness facilitating plastic deformation of the elongate member within the region of reduced thickness. Preferably, outside the at least one weakened region, the elongate member is substantially rigid, that is resists deformation when subjected to a force sufficient to deform the weakened region of the elongate member. In one embodiment, the or each weakened region of the elongate member is preferably oriented to facilitate deforming the elongate region to form a retaining formation extending to one side of the elongate member. Preferably the weakened region facilitates forming a retaining formation that extends in a direction from the elongate member opposite to the securing portion. In this way, the retaining formation is formed in the correct orientation for engaging with the lower edge of the slate and holding the slate in position. In an alternative embodiment, the or each weakened region of the elongate member is formed by a providing the weakened region with a reduced diameter around its circumference. In this way, the form of the or each weakened region allows the retaining formation to be formed at any required angle and extend in any required direction from the elongate member. The elongate member may be any suitable length. The length of the elongate member refers to the distance between the first and second ends of the elongate member. For example, the elongate member may be at least 4 cm in length, preferably at least 6 cm in length, still more preferably at least 8 cm in length, most preferably at least 10 cm in length. The elongate member may be up to 18 cm in length, preferably up to 16 cm in length, still more preferably up to 14 cm in length, most preferably up to 12 cm in length. In some preferred embodiments, the elongate member may be from 4 to 18 cm in length, preferably from 6 to 16 cm in length, more preferably from 8 to 14 cm in length, most preferably from 10 to 12 cm in length. The at least one weakened region is spaced from the second end of the elongate member by a distance sufficient to allow the elongate member to be bent to form a hook or other retaining form to hold the slate in place. The at least one weakened region is preferably spaced from the second end of the elongate member by a distance of at least 4 mm, preferably at least 6 mm, still more preferably at least 8 mm, most preferably at least 10 mm. The at least one weakened region is preferably spaced from the second end of the elongate member by a distance of up to 50 mm, preferably up to 40 mm, still more preferably up to 30 mm, most preferably up to 20 mm. In some embodiments, the at least one weakened region is spaced apart from the second end of the elongate member by a distance of from 4 to 50 mm, preferably from 6 to 40 mm, more preferably from 8 to 30 mm, most preferably from 10 to 20 mm. In use, the plastically deformable portion may be bent or deformed by the application of a force to define a retaining form, such as a hook, adapted to retain and support a slate on a structure. Plastic deformation will occur preferentially within the at least one weakened region of the plastically deformable portion of the elongate member when the force is applied. In this manner, deformation of the elongate member can be advantageously controlled. In particular, plastic deformation of the elongate member will only occur within the at least one weakened region of the plastically deformable portion, in use. The plastically deformable portion of the slate retaining device can therefore be bent accurately and in a reproducible manner. In some embodiments, the plastically deformable portion may comprise a plurality of weakened regions, for example at least two weakened regions, preferably at least three weakened regions, more preferably at least four weakened regions, most preferably at least five weakened regions. In embodiments comprising a plurality of weakened regions, the plastically deformable portion may be bent or deformed in a number of locations (i.e. within one or more of the weakened regions) by the application of a force to define hooks having a variety of shapes. In this manner, the slate retaining device can be adapted to retain and support slates of different sizes and at different heights on a roof structure. Advantageously, embodiments comprising a plurality of weakened regions can be used to retain slates on roof structures having non-standard or irregular batten spacings. In a second aspect of the present invention, there is provided a method of retaining a slate on a structure, the method comprising: providing a slate retaining device according to the first aspect of the present invention; affixing the securing portion of the slate retaining device to the structure; manoeuvring the slate over the slate retaining device so that the plastically deformable portion extends beyond a bottom edge of the slate; applying a force to the plastically deformable portion to cause plastic deformation of the at least one weakened region of the slate retaining device to form a retaining formation; wherein the bottom edge of the slate is retained by the retaining formation. The securing portion of the slate retaining device may be affixed to the structure using any suitable means. For example, where the securing portion comprises a spike, as described above, the spike may simply be driven into the structure, for example using a hammer. Where the securing portion comprises an opening, such as a slot or eyelet, the securing portion may be affixed to the structure by driving a nail or screw through the opening and into the underlying structure. Once the slate retaining device has been affixed to the structure, a slate is manoeuvred over the slate retaining device, such that the slate retaining device is positioned between the slate and the structure. A majority of the slate retaining device, including the securing portion, may be covered by the slate. However, the plastically deformable portion extends beyond a bottom edge of the slate. The bottom edge of the slate refers to the lowermost edge of the slate, when the slate is correctly positioned over the slate retaining device. Preferably, only the plastically deformable portion of the slate retaining device extends beyond the bottom edge of the slate. Once the slate is correctly positioned over the slate retaining device, a force is applied to the plastically deformable portion to cause plastic deformation of the weakened region of the slate retaining device to form a retaining formation, such as a hook. The retaining formation holds the bottom edge of the slate, thereby fixing the slate to the structure. Preferably, the force is applied at the second end of the elongate member using a suitable tool to bend the plastically deformable portion about the at least one weakened region. In some embodiments, the force is applied to the plastically deformable portion of the slate retaining device using a hand tool. The hand tool preferably comprises means for applying leverage to the second end of the elongate member to deform the plastically deformable portion about the weakened region. Suitable tools include pliers, pincers or grips. Alternatively a specialist tool may be used. In one embodiment the tool comprises an elongate handle having an opening in one end or end portion, for example a blind hole formed in one end of the handle. The opening may have any suitable form that accommodates the portion of the elongate member at the second end of the elongate member. For example, in embodiments where the elongate member is a rod having a circular cross section, the opening has an internal diameter equal to or greater than the diameter of the second end of the elongate member of the slate retaining device. Preferably, the opening extends along a longitudinal axis of the handle. In use, the second end of the elongate member is inserted into the opening and a force is applied to the handle to bend the plastically deformable portion of the elongate member about the at least one weakened region. Accordingly, in a third aspect of the present invention, there is provided a kit comprising a slate retaining device according to the first aspect of the present invention and a tool for applying a force to the plastically deformable portion of the slate retaining device to cause plastic deformation of the weakened region. Slate retaining devices, methods, and kits according to the present invention may be used to replace damaged or missing slates on roof structures, without removing, damaging, or otherwise disturbing adjacent slates, including underlying and overlying rows of slates. For example, in one embodiment, the securing portion of the slate retaining device may be driven into the batten of a roof between underlying slates. A replacement slate may then be manoeuvred over the slate retaining device and slid between the underlying and overlying rows of slates so that the plastically deformable portion of the slate retaining device extends beyond a bottom edge of the replacement slate. A force is then applied to cause plastic deformation of the at least one weakened region of the slate retaining device to form a retaining formation, such as a hook, which retains the replacement slate on the roof structure. Deforming the slate retaining device to form a retaining formation, such as a hook, only after the replacement slate has been manoeuvred into position is advantageous. In particular, the retaining formation does not obstruct the passage of the replacement slate as it is slid between the overlying and underlying slates in adjacent rows. The replacement slate can therefore be slid into position without having to angle the slate to avoid obstruction by the retaining formation. In this manner, the replacement slate can remain flat against the underlying slates as it is slid into position, thereby preventing accidental damage to the replacement slate or slates in adjacent rows. The slate retaining device, which may be substantially rigid outside the at least one weakened regions, nevertheless retains the slate securely and at the correct height on the roof structure. The retaining formation, once formed, is also discrete and does not detract from the appearance of the roof. To further improve the appearance to the slate retaining device, at least the plastically deformable portion may be painted. For example the plastically deformable portion may be painted to closely match the colour of the replacement slate, so that when it is deformed to form a retaining formation, the visible portion of the formation retaining the replacement slate does not stand out against the replacement slate. Slate retaining devices and kits according to the present invention are simple to produce and low cost. In particular, slate retaining devices according to the present invention can be produced as a single component using less material and fewer manufacturing steps than known slate retainers, such as those disclosed in GB2473637B. Embodiments of the present invention will now be described by way of example only, having reference to the accompanying drawings, in which: Figure 1 is a side view of a slate retaining device according to a first embodiment of the present invention in a first configuration; Figure 2 is a side view of the slate retaining device of Figure 1 in a second configuration; Figures 3-6 illustrate the slate retaining device of Figure 1 in use; Figure 7 is a side view of a slate retaining device according to a second embodiment of the present invention in a first configuration; Figure 8 is a side view of the slate retaining device of Figure 7 in a second configuration; Figure 9a is a perspective view of a tool for use in a kit according to the present invention; Figure 9b is a cross sectional view of the tool of Figure 9a; Figures 10a and 10b illustrate the tool of Figures 9a and 9b, in use; and Figure 11 is a side view of a slate retaining device according to a third embodiment of the present invention in a first configuration. For ease of explanation, like numbers have been used throughout the Figures to indicate analogous features of each embodiment. Turning now to Figure 1, there is shown a slate retaining device, indicated generally as 10, in a first configuration. The slate retaining device 10 comprises an elongate member 20, for example a rod, having a first end 21, and a second end 22. The first end 21 of the elongate member 20 includes a securing portion 30. The securing portion 30 comprises a spike 31 extending at an acute angle from the first end 21 of the elongate member 20. In use, the securing portion 30 may be affixed to a structure, for example a roof batten, by driving the spike 31 into the structure, using a tool such as a hammer. The slate retaining device 10 includes a plastically deformable portion 40 formed adjacent the second end 22 of the elongate member 20. The plastically deformable portion 40 includes a weakened region 41 in the form of an indent in the surface of the elongate member 20, spaced apart from the second end 22. The weakened region 41 facilitates plastic deformation of the plastically deformable portion 40 of the elongate member 20. In particular, the thickness of the elongate member 20 is reduced by the indent within the weakened region 41. Under the application of a sufficient force to the elongate member 20, plastic deformation will occur preferentially within the weakened region 41 of the plastically deformable portion 40. The remainder of the elongate member 20 outside the weakened region 41 is substantially rigid, that is resists deformation when subjected to the force sufficient to deform the elongate member at the weakened region 41. In this manner, deformation of the elongate member 20 can be controlled. In particular, plastic deformation of the elongate member 20 can be constrained within the weakened region 41 of the plastically deformable portion 40, in use. Figure 2 shows the slate retaining device 10 of Figure 1 in a second configuration, following deformation of the plastically deformable portion 40 of the elongate member 20. As can be seen in Figure 2, plastic deformation has occurred only within the weakened region 41 of the elongate member 20. In this configuration, the second end 22 of the elongate member 20 defines a retaining formation in the form of a hook 50 adapted to retain a slate on a structure, such as a roof, as described in more detail below, with reference to Figures 3-6. As shown in Figure 2, the hook 50 extends away from the elongate member 20 on the opposite side of the elongate member to the spike 31. This is facilitated by appropriate formation of the weakened region 41, for example by forming the indent in the weakened region 41 to extend laterally across the elongate member 20, perpendicular to both the hook 50 and the spike 31. Figures 3-6 illustrate the slate retaining device of Figures 1 and 2, in use. In particular, Figures 3-6 illustrate a method of fixing a slate to a roof structure without 20 removing or disturbing adjacent slates, as may be necessary when replacing a damaged or missing slate. Turning first to Figure 3, there is shown a cross section of a roof structure indicated generally as 100, comprising roof battens 110, 111. A first slate 120 is secured to the roof structure 100. A slate retaining device 10 is provided. The slate retaining device 10 is affixed to an underlying roof batten 111 by the securing portion 30, for example by driving the spike 31 located at the first end 21 of the elongate member 20 into the underlying batten 111 using a suitable tool such as a hammer. As shown in Figure 4, a second slate 121, for example a replacement slate, is then maneuvered over the slate retaining device 10 and beneath the first slate 120. As shown in Figure 5, the second slate 121 can be slid unobstructed over the slate retaining device 10 and beneath the first slate 120, so that the plastically deformable portion 40 of the slate retaining device 10 extends beyond a bottom edge of the slate 121. As shown in Figure 6, once the second slate 121 has been maneuvered to the correct position (for example in line with adjacent slates), a force is applied to the second end 22 of the elongate member 20 to cause plastic deformation within the weakened region 41 of the plastically deformable portion 40. Following deformation of the plastically deformable portion 40 of the elongate member 20, the second end 22 of the elongate member 20 defines a hook 50. The hook 50 retains the second slate 121 on the roof structure 100 by engaging with the lower edge of the slate and preventing it from sliding from beneath the first slate 120, for example under the action of gravity. In Figure 7 there is shown a slate retaining device according to a second embodiment of the invention, indicated generally as 210, in a first configuration. The slate retaining device 210 is formed from an elongate member 20, having a first end 21, and a second end 22. The first end 21 of the elongate member 20 includes a securing portion 30. The securing portion 30 comprises a spike 31 protruding at an acute angle from the first end 21 of the elongate member 20. In use, the securing portion 30 may be affixed to a structure, for example a roof batten, by driving the spike 31 into the structure, for example using a hammer. A plastically deformable portion 40 is formed adjacent the second end 22 of the elongate member 20. The plastically deformable portion 40 includes a plurality of weakened regions 41, 42, 43 in the form of indents in the elongate the member 20, spaced apart from the second end 22. In Figure 8 there is shown the slate retaining device 210 of Figure 7 in a second configuration, following deformation of the elongate member 20 within weakened regions 42 and 43 of the plastically deformable portion 40. In this configuration, the second end 22 of the elongate member 20 defines a hook 250 adapted to retain a slate on a structure, such as a roof. The slate retaining device 210 shown in Figures 7 and 8 can be deformed within any one or more of the weakened regions 41, 42, 43 to form hooks of a variety of different shapes and retain slates of different sizes. The slate retaining device 210 can also be deformed within any one or more of the weakened regions 41, 42, 43 to form hooks adapted to securely retain slates on structures at varying heights, for example roof structures having non-standard or irregular batten spacings. Turning to Figure 9a, there is shown a perspective view of a tool, indicated generally as 300, for applying a force to the plastically deformable portions 40 of the slate retaining devices 10, 210 shown in Figures 1-8, to cause plastic deformation in the weakened region(s) 41,42, 43 of the plastically deformable portions 40. In Figure 9b there is shown a cross-sectional view of the tool 300 of Figure 9a. The tool 300 comprises a handle 310 and blind hole 320 formed in one end and extending along a longitudinal axis X of the handle. The blind hole 320 has an internal diameter that is equal to or greater than the diameter of the elongate member 20. Figures 10a and 10b illustrate a method of applying a force F to the plastically deformable portion 40 of a slate retaining device 10. The securing portion (not shown) at the first end of the slate retaining device 10 is fixed to a structure, for example a roof batten. As shown in Figure 10a, the second end 22 of the slate retaining device 10 is inserted into the blind hole 321 in an end of the handle 310. A force F is then applied to handle 310 to plastically deform the elongate member 20 about the weakened region 41 to form a hook 50 adapted to retain a slate, as shown in Figure 10b. Turning now to Figure 11, there is shown a slate retaining device according to a third embodiment of the invention, indicated generally as 410, in a first configuration. The slate retaining device 410 comprises an elongate member 20, for example a rod, having a first end 21, and a second end 22. The first end 21 of the elongate member 20 includes a securing portion 30. The securing portion 30 comprises a spike 31 extending at an acute angle from the first end 21 of the elongate member 20. The slate retaining device 410 includes a plastically deformable portion 40 formed adjacent the second end 22 of the elongate member 20. The plastically deformable portion 40 includes a weakened region 44 in the form of a region of the elongate member 20 having a reduced thickness around its circumference, spaced apart from the second end 22. 5 The weakened region 44 facilitates plastic deformation of the plastically deformable portion 40 of the elongate member 20. The slate retaining device 410 can be used in methods of fixing a slate to a roof structure, as described above. Advantageously, the form of the weakened region 44 10 allows a retaining formation to be formed at any required angle and extend in any required direction from the elongate member 20.

Claims

10 07 231. A slate retaining device for use in replacing a slate on a roof structure between underlying and overlying rows of slates comprising:5 an elongate member having a first end and a second end;wherein the first end of the elongate member comprises a securing portion, for securing the slate retaining device to a structure; andwherein the elongate member comprises a plastically deformable portion adjacent the second end having at least one weakened region spaced apart from the 10 second end to facilitate plastic deformation of the elongate member.

2. The slate retaining device according to claim 1, wherein the elongate member is formed from metal.15   3. The slate retaining device according to claim 1 or claim 2, wherein the securingportion comprises an opening.

4. The slate retaining device according to claim 1 or claim 2, wherein the securing portion comprises a spike.

205. The slate retaining device according to any preceding claim, wherein the at least one weakened region comprises one or more of an indent formed in the surface of the elongate member, a flattened region of the elongate member, and a region of the elongate member having a reduced thickness around its circumference.10 07 236. The slate retaining device according to any preceding claim, wherein outside the at least one weakened region, the elongate member is substantially rigid.

7. The slate retaining device according to any preceding claim, wherein the 5 elongate member is from 4 to 18 cm in length, preferably from 6 to 16 cm in length, more preferably from 8 to 14 cm in length, most preferably from 10 to 12 cm in length.

8. The slate retaining device according to any preceding claim, wherein the at10 least one weakened region is spaced apart from the second end of the elongate member by a distance of from 4 to 50 mm, preferably from 6 to 40 mm, more preferably from 8 to 30 mm, most preferably from 10 to 20 mm.

9. The slate retaining device according to any preceding claim, wherein the 15 plastically deformable portion comprises a plurality of weakened regions.

10. A method of retaining a slate on a structure, the method comprising: providing a slate retaining device according to any of claims 1-9;affixing the securing portion of the slate retaining device to the structure;20 manoeuvring the slate over the slate retaining device so that the plastically deformable portion extends beyond a bottom edge of the slate;applying a force to the plastically deformable portion to cause plastic deformation of the at least one weakened region of the slate retaining device to form a retaining formation;25         wherein the bottom edge of the slate is retained by the retaining formation.

11. The method according to claim 10, wherein the retaining formation is a hook.10 07 2312. The method according to claim 10 or claim 11, wherein force is applied to the plastically deformable portion of the slate retaining device using a hand tool.

513. The method according to claim 12, wherein the hand tool comprises an elongate handle having a blind hole formed in an end of the handle.

14. The method according to claim 13, wherein the blind hole extends along a 10 longitudinal axis of the handle.

15. The method according to claim 13 or claim 14, wherein applying a force to the plastically deformable portion of the slate retaining device comprises inserting the second end of the elongate member into the blind hole and applying the force to the 15 handle.

16. A kit comprising a slate retaining device according to any of claims 1-9 and a tool for applying a force to the plastically deformable portion of the slate retaining device.2017. A kit according to claim 16, wherein the tool comprises an elongate handle having a blind hole formed in an end of the handle.

18. A kit according to claim 17, wherein the blind hole extends along a longitudinal 25 axis of the handle.

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