- 1 PROTECTIVE BARRIER FIELD 5 The present invention relates generally to the protection of building structures against deterioration and/or destruction. In one form, the present invention relates to protective 10 barriers for building structures and to methods of installing and/or forming the protective barriers around the foundations of the building. In one form, the present invention relates to protective 15 barriers for building structures in which the protective barrier is formed by one or more layers, coatings or components which cooperate with each other to provide protection for the building structure against deterioration and/or destruction from selected causes. 20 The present invention finds particular application as a protective barrier and method of applying or installing a protective barrier around the edges of a concrete slab forming the foundation of a building structure and along 25 the lower edges of the wall of the building mounted on the concrete slab. Although the present invention will be described with particular reference to one or more embodiments of the 30 protective barrier, it is to be noted that the scope of protection is not restricted to the described embodiments but rather the scope of protection is more extensive so as to include other forms and arrangements of the layers 6241738_1 (GHMatters) P98381.AU.1 JMC - 2 and/or components of the protective barrier and/or of the methods of applying and/or installing the protective barriers than specifically described. 5 BACKGROUND Building structures are subjected to deterioration over the life of the building from a variety of different causes. Some of the causes of deterioration of the 10 building include old age, weathering, poor workmanship, the selection of unsuitable building materials and components for the construction techniques used in constructing the building and/or for the environment in which the building construction is formed, insect pests, 15 lack of maintenance and other causes. Some of the more usual causes of deterioration of a building structure are water damage, both external water damage, such as the ingress of water into the building 20 from external sources of water, and internal water damage, such as for example, moisture penetrating the exterior and internal walls and floor of a building/or damage by moisture being transmitted through the structure of the building, such as through the walls and floor by capillary 25 action or similar. In the past, there have been attempts to ameliorate the effects of water penetration or capillary action of water within the components of the building. However, such attempts have not all been satisfactory. 30 In addition to water damage, included amongst the more insidious causes of deterioration of buildings, are infestations of pests, including animal pests, insect 6241738_1 (GHMatters) P98381.AU.1 JMC - 3 pests, and the like. Examples of insect pests which cause damage are ants, white ants, termites, spiders and other similar infestations. 5 When constructing a new building, it is desirable to provide as much protection as possible against deterioration caused by water, moisture, pest infestation and similar. Usually, individual solutions dedicated to reducing or preventing deterioration from a single cause 10 are used during construction of the building, such as for example, separate water impermeable membranes, separate damp proof courses, separate termite resistant barriers, separate barriers for animals, including sealing all access points of the building through which such damage 15 causing materials or organisms can gain access, such as by closing all access points with expanded foam compositions and the like. However, providing separate solutions or components having a single dedicated function only is expensive and time consuming. Additionally, the different 20 solutions, components and forms of protection used within the one building need to be compatible with one another to be effective. The conflicting requirements of the different solutions often results in compromises being made as to the selection of the particular solution so 25 that the overall protection provided by the selected combination of solutions is less than ideal. Therefore, there is a need to provide a protective barrier or protective barrier system, or protective barrier component which has more than a single function so that the issues 30 of compatibility of different treatments, is reduced or eliminated and the cost of having to supply and install different components or treatments is reduced to be more aligned with the cost of providing a single component or 6241738_1 (GHMatters) P98381.AU.1 JMC - 4 treatment and/or installation of the single component or treatment within the building. Accordingly, it is an aim of the present invention to 5 provide a protective barrier having more than a single function. Accordingly, it is an aim of the present invention to provide a method of installing or providing a protective 10 barrier which has more than a single function. Accordingly, it is an aim of the present invention to provide a protective barrier for a building structure which is a combined pest resistant treatment, water 15 impermeable membrane and a satisfactory damp proof course. Accordingly, it is an aim of the present invention to provide a building structure having a protective barrier which protects the building structure against 20 deterioration for more than a single course. One problem associated with using slab construction for the foundation of a building structure, such as a domestic dwelling is that the edges of the slab are often poorly 25 formed, irregular or are not provided with the correct configuration upon which to build the walls of the structure. Accordingly, further remedial work is required on the edges of the slab to make the slab compatible with the type of construction being formed on the slab, such as 30 for example, the use of building panels for the facade of the building. The additional work required around the edges of a 6241738_1 (GHMatters) P98381.AU.1 JMC - 5 concrete slab is often referred to as slab edge detailing. When using lightweight building panels in the building construction, slab edge detailing of residential homes is costly and time consuming in many instances, for a variety 5 of different reasons. Some of the reasons include builders of the homes do not want to change the construction drawings upon which the building they are constructing is based from a drawing 10 showing a brickwork slab edge to reflect the different requirements of a slab edge for use with building panels, both in terms of the depth and height of the rebate along the outer edge of the slab to be complementary to the dimensions of the building panel to accommodate the 15 lightweight building panels to ensure such panels are installed above the level of the ground to provide improved resistance against deterioration, such as for example from the ingress of moisture and/or insect pests. The reason for the rebates being of different sizes is the 20 difference in dimensions of a wall constructed from bricks as compared to the dimensions of a wall formed by panels. Concreters forming the concrete slab as the foundation for the home rarely produce a slab having linear or straight 25 edges or sides or even an accurately sized and shaped slab, which often leads to either the edges of the slab having to be chipped away to form a more or less linear or straight edge, or excess materials such as fillers, having to be applied to the edges of the slab to, in effect, 30 straighten the edge of the slab to be compatible with receiving the lower ends of the lightweight building panels collectively within the edge rebate or along the side of the slab. 6241738_1 (GHMatters) P98381.AU.1 JMC - 6 Thus, there is a need for a protective barrier and a method of forming a protective barrier that can be applied to concrete slabs used as the foundation for a building 5 structure which are less time consuming to construct and/or which are less costly to form and which are more readily adapted to accommodate the use of lightweight building panels in place of the more usual bricks for forming the walls of the building. 10 Accordingly, it is an aim of the present invention to provide a protective barrier and method of installing or applying a protective barrier to a concrete slab edge that can accommodate the variations in the edges or sides of 15 the slab from being non-linear and not being in accordance with the plans of the slab so as to allow the economical use of lightweight building panels in the construction of the building. 20 SUMMARY Thus, there is a need for a protective barrier and a method of forming a protective barrier that can be applied 25 to concrete slabs used as the foundation for a building structure which are less time consuming to construct and/or which are less costly to form and which are more readily adapted to accommodate the use of lightweight building panels in place of the more usual bricks for 30 forming the walls of the building. Accordingly, it is an aim of the present invention to provide a protective barrier and method of installing or 6241738_1 (GHMatters) P98381.AU.1 JMC applying a protective barrier to a concrete slab edge that can accommodate the variations in the edges or sides of the slab from being non-linear and not being in accordance with the plans of the slab so as to allow the economical 5 use of lightweight building panels in the construction of the building. SUMMARY 10 According to one form of the present invention, there is provided a protective barrier for preserving a building structure, the building structure having at least a first part and a second part, the protective barrier comprising (A) a first layer of a first material having a first part 15 and a second part, the first part of the first layer applied to the first part of the building structure, and the second part of the first layer applied to the second part of the building structure, so that the first layer extends between the first part of the building structure 20 and the second part of the building structure to form a substantially continuous layer therebetween for forming part of the protective barrier, and (B) a second layer of a second material having a first part and a second part, the first part of the second layer being applied to the 25 first part of the building structure, and the second part of the second layer being applied to the building structure so that the first part of the first layer is located intermediate the first part of the building structure and the second part of the second layer to at 30 least partially overlie the first part of the first layer, wherein the second part of the second layer is provided with an indicator for facilitating inspection of the building, the indicator being arranged and/or located so 6241738_1 (GHMatters) P98381.AU.1 JMC - 8 that the second part of the first layer underlying the second part of the second layer is visible through the second part of the second layer for observing the state of the underlying first layer to provide information about 5 the building. According to one form of the present invention, there is provided a method of preserving a building structure having a first part and a second part by forming a 10 protective barrier on the building structure, the protective barrier reducing deterioration of the building structure, the method comprising the steps of contacting the building structure with a first layer of a first material, so that a first part of the first layer is 15 applied to the first part of the building structure and a second part of the first layer is applied to the second part of the building structure, the first layer extending between the first part of the building structure and the second part of the building structure, to form a 20 substantially continuous layer therebetween, contacting the building structure with a second layer of a second material, so that a first part of the second layer is in contact with the first part of the building structure and the first part of the first layer is located intermediate 25 the first part of the building structure and a second part of the second layer so that the second part of the second layer at least partially overlies the first part of the first layer wherein the second part of the second layer is provided with an indicator for providing an indication of 30 the state of the second part of the first layer underlying the second part of the second layer and using the indicator to determine the state of the first layer to provide information about the building. 6241738_1 (GHMatters) P98381.AU.1 JMC - 9 According to one form of the present invention, there is provided a building structure having a protective barrier, the building structure having a first part and a second 5 part, the protective barrier comprising a first layer and a second layer, the first layer of a first material having a first part and second part, the first part of the first layer being applied to the first part of the building structure and the second part of the first layer being 10 applied to the second part of the building structure, the first layer extending between the first and second parts of the building structure to form a substantially continuous layer therebetween, a second layer of a second material having a first part and a second part, the first 15 part of the second layer being applied to the first part of the building structure, the second part of the second layer being such that the second part of the first layer is located intermediate the first part of the building structure and the second part of the second layer so that 20 the second part of the second layer at least partially overlies the second part of the second layer, the second layer being provided with an indicator for providing information about the state of the first layer to assist in preserving the building structure against 25 deterioration. BRIEF DESCRIPTION Forms of the building structure to which protective 30 barriers can be applied, include domestic dwellings, residential homes, garages, workshops, factories, and include any form of domestic, commercial or industrial building structure or the like. 6241738_1 (GHMatters) P98381.AU.1 JMC - 10 In one form, the first part of the building structure is a wall member, wall element, or similar. However, the first part of the structure can be any part of a building, such 5 as for example, building components made from a variety of different materials and in a variety of different forms. Forms of the building components include components made from timber, metal, clay, ceramic, concrete, substitutes for concrete or the like. Forms of the components include 10 lengths, blocks, bricks, tiles, extrusions or the like. Typically, the first part of the building structure is a lightweight building panel, typically in the form of an autoclaved aerated concrete building panel (AAC). Preferably, the AAC panel is manufactured by CSR Building 15 Products Limited and supplied under the HEBEL@ trade mark, such as for example, the HEBEL@ PP XL system incorporation Hebel Power Panel XL which is a less dense form of the more usual Hebel Power Panel and having a lighter overall weight, typically up to about 20% less weight than the 20 usual HEBEL@ panel. However, the first part of the building structure can take any suitable form or arrangement and be of any suitable type, including being provided with any form of surface preparation or treatment. 25 Although the second part of the building structure can be any type, form, shape, component, typical forms include the foundation of the building. 30 In one form, the second part of the building structure, is a foundation member, element, assembly, installation or arrangement. In one form, the foundation can be a block or brick wall or edge. However, it is more usual that the 6241738_1 (GHMatters) P98381.AU.1 JMC - 11 foundation is typically made from concrete, including reinforced concrete, such as for example, a concrete slab foundation, more typically a reinforced concrete slab foundation of the type provided as the foundation of a 5 domestic dwelling. Preferably, the concrete slab has a rebate located at or towards or along one or more edges, typically along the upper end or upper edge in use. Forms of the rebate extend around all of the perimeter of the slab, in which, or upon which, the first part of the 10 building structure i.e. the lightweight building panel, is located to extend upwardly from the concrete slab to form a wall or part of a wall of the building, typically the external walls of the building. In one form, the rebate has a base or floor section, or substantially horizontal 15 section and a side wall or substantially vertical section. The floor or base section corresponds to the width dimension of the rebate, and the side wall corresponds to the height dimension or depth of the rebate. In one form, the width of the rebate of the concrete slab is greater 20 than the corresponding thickness of the building panel, to allow the panel to be received uprightly in the rebate for supporting the building panel, typically above the level of the surrounding soil to protect the building panel from deterioration by contact with the soil surrounding the 25 building. In one form, the building panel is joined to the rebate of the slab using a suitable bonding material, such as a layer of an adhesive, mortar, cement, sealant or similar, 30 located intermediate the lower end or edge of the panel in use and the floor or base section or surface of the rebate, i.e. the width of the rebate. As preferred bonding agent is Hebel@ Mortar or Hebel@ Adhesive. In one 6241738_1 (GHMatters) P98381.AU.1 JMC - 12 form the thickness of the layer of bonding agent is up to about 3mm. In one form, there is an optional additional layer 5 intermediate the bonding layer and the base section of the rebate. In one form, the optional intermediate layer is a slip layer for allowing movement, albeit preferably slight movement of the building panel with respect to the concrete slab. In one form, the intermediate layer is a 10 water resistant layer, preferably a water impermeable layer, such as a membrane, typically in the form of a damp proof course or damp proof layer. In one form, it is preferred that the building panel not be directly bonded to the concrete slab. 15 One form of the first material of the first layer is a pest resistant layer, typically a layer for resisting the ingress of insects, spider and other forms of pests. In one form, the insect resistant layer is a termite 20 resistant layer. One form of the termite resistant layer is Termiblock Termicide supplied by Granitgard Pty Ltd. One form of the first layer is a sealant, typically an elastomeric sealant which is able to accommodate movement 25 of the first part of the building, typically, with respect to the second part of the building. Other additives are included in the first layer or with the first material. Typically, the first part of the first layer is in contact 30 with the lightweight building panel. More typically, the first part of the first layer can be applied by any suitable means, such as brush, roller, trowel or by spraying to the lower end of the lightweight building 6241738_1 (GHMatters) P98381.AU.1 JMC - 13 panel or onto any pretreatments applied to the surface of the lightweight building panel. Typically, the first part of the first layer is located vertically at a higher level than the location of the second part of the first layer. 5 In one form, at least a part of the first part of the first layer is located below the level of the soil around the edge of the building. In one form, part of the first part and all of the second part of the first layer is not 10 in contact with the soil around the perimeter of the building. However, other arrangements and variations are possible. In one form, the second part of the first layer is in 15 contact with the concrete slab, typically, the edge of the concrete slab, more typically, the side edge of the concrete slab, or side edge of the slab below the rebate. In one form, the second part of the first layer extends beneath the level of the earth surrounding the concrete 20 slab, typically to well below the edge of the rebate along the side edge of the rebate. In one form, the length or width of the first part of the first layer is at least about 50mm, typically about 75mm, 25 more typically at least about 100mm, preferably greater than about 125mm. Typically, the length or width of the second part of the first layer is at least about 50mm, typically at least 30 about 75mm, and more typically at least about 100mm and preferably greater than about 125mm with respect to the position of the floor of the rebate. 6241738_1 (GHMatters) P98381.AU.1 JMC - 14 In one form, the first layer is of a linear shape or is in a stepped or staggered shape covering both the vertical and horizontal surfaces of the concrete slab or retaining wall forming the foundation of the building. 5 The first part of the first layer and the second part of the first layer form a continuous layer extending from one to the other and covering both the lower end of the building panel and the upper side edge of the concrete 10 slab to form a more or less continuous barrier. One form of the first layer, typically the Termiblock Termicide, has a thickness of about 2.5mm when wet. However, the layer may be of any convenient, desirable or 15 functional thickness. In one form, the layer of Thermiblock can be reinforced with a suitable reinforcement, such as for example, a reinforcement fabric, typicallly, an integrated 20 reinforcement fabric. The reinforcement fabric, if used, can assist in dispersing and/or spreading the stress caused by movement and stretching of the substrate, either, the building panel or concrete slab to which the layer is applied. 25 The first layer may be applied as a layer, sheet, bead, patch, joint, line, area or the like. One form of the second layer is a water or moisture 30 impervious or impermeable layer. The layer can take any suitable form or composition. In one form, the second layer is a render or texture layer 6241738_1 (GHMatters) P98381.AU.1 JMC - 15 or coating. In one form, the first part of the second layer is exposed to atmosphere whereas the second part of the second layer is located lower than the soil level around the building. 5 In one form, part of the second part of the second layer is exposed to atmosphere and another part of the second layer is in contact with the soil around the perimeter of the building. 10 In one form, the first part of the second layer can have any convenient, desirable or functional length or width such as for example, extending to an amount greater than about 100mm. 15 In one form, the second part of the second layer has a length or width of a minimum of about 100mm, preferably greater than about 150mm above the soil line. 20 In one form, there is an optional third layer. In one form, the third layer is in contact with both the building panel and the side of the concrete foundation slab. One form of the third layer is a primer layer. Forms of the primer layer include a sealant, mortar or similar. 25 In one form, the third layer, in the form of the primer layer, is applied to the building structure prior to the application of the first layer of first material. 30 In one form, there are three layers being the primer layer, the first layer, and the second layer in which the first layer is located between the two parts of the building and also at least in part, the first part of the 6241738_1 (GHMatters) P98381.AU.1 JMC - 16 primer layer, if present, and the first part of the second layer. One form of the second material from which the second 5 layer is made is an exterior coating, including a render or texture coating. Forms of the texture or render coating include or contain acrylic material, urethanes, polyesters, or other suitable 10 materials, particularly water soluble coatings or similar. Any suitable surface coating can be used as the second material. In one form, the second material is a render, more 15 typically, a render coating, even more typically, a combined render and/or texture coating or material. In one form, the first part of the render is applied to the building panel, typically directly to the building 20 panel. In some forms, a primer layer is located intermediate the surface of the building panel and the second layer. In one form, the first part of the first layer is located 25 intermediate the building panel and the second part of the second layer in the form of a render or similar. Forms of the building panel can further comprise a coating or one or more layers of coatings. Typically, the 30 coatings include coatings which are (i) durable or contribute to the longevity of the building panel, (ii) enhance the appearance of the building panel, and/or contribute to the weather resistance of the building 6241738_1 (GHMatters) P98381.AU.1 JMC - 17 panel. In one form, the second part of the second layer is provided with an indicator. In one form, the indicator is 5 provided at or towards the lower end of the second layer, more typically in the upper part of the second part of the second layer which is located at a level lower than the first part of the second layer. In one form, the indicator is a discontinuity through the thickness of the 10 render layer. In one form, the indicator is provided in the render and/or texture coating or layer. 15 In one form, the indicator is formed in the second part of the second layer of the second material, i.e. in the lower part of the render coating. Preferably, the indicator is located in the lower part of the render coating. One form of the indicator is a discontinuity in the render coating, 20 typically a discontinuity through the thickness of the render coating, more typically a discontinuity through the entire thickness of the coating to expose the termite resistant coating of the first layer therebehind, so as to be visible through the render coating. 25 In one form, the indicator is a groove, channel, notch, line or similar. The indicator line may be continuous or segmented so that the underlying termite resistant coating is exposed and visible along the length of the wall or at 30 strategic spaced apart locations. However, it is preferred that the indicator being continuous along each wall, preferably around the entire perimeter of the building. The groove may have any suitable shape, 6241738_1 (GHMatters) P98381.AU.1 JMC - 18 profile, cross section or the like. In one form, the profile is square or rectangular having linear or straight walls. In other forms, the profile is provided with inclined walls. Typically, the line is tapered. One 5 preferred form is a V-shaped groove, channel, notch, joint or similar, typically an inwardly directed taper having a relatively wider width at the distal end or mouth of the groove, and a relatively narrow width at the proximal end adjacent the termite resistant coating. 10 The V-shaped groove or joint in one form, is linear, such as being straight, whereas in another form, the V-shaped groove is non-linear, such as for example, being curved, staggered, stepped or other to take into account the 15 topography or terrain upon which the building is constructed, and/or the style or design of the building. Even if the indicator is non-linear, it is preferably continuous. 20 In one form, the wall, or more particularly the first layer, is provided with a guide. In one form, the guide is a row or line of markers. One form of the markers include fasteners, such as for example, nails or similar. 25 In one form, the location of the indicator groove corresponds to the location of the guide, such as the row of nails. Typically, the groove forming the indicator is formed along the row of nails outlining the maximum soil line or soil level, or is formed in alignment with the 30 level of the soil. The nails located in the second layer, typically through the first layer, and optionally the primer layer, are then 6241738_1 (GHMatters) P98381.AU.1 JMC - 19 removed before the texture/render coating finally cures and dries and the final paint coat or surface treatment or coating, applied to the exterior of the building. 5 In one form, the indicator provides an indication of the state of the inner layer or termite resistant layer such as whether the inner layer is intact and functioning as required or has degraded, whether the inner layer is subject to attack and/or degradation by pests, such as 10 insect pests including termites and/or similar. In one form, the location of the indicator is such that the indicator is exposed so as not to be covered by the earth or ground surrounding the building construction to 15 enable the V-shaped joint to be inspected so as to view the first layer underlying the V-shaped notch or joint. In one form, the location of the indicator is determined by the location of the nail line or similar corresponding 20 to the upper level of soil against the sides of the foundation of the building. In one form, the second part of the second layer is partially exposed and partially covered. In one form, 25 there is at least a length or width of exposure by which the second layer is uncovered with soil or earth having minimum length or width of 75mm calculated from the location of the indicator, typically greater than 100mm, more typically greater than 125mm. 30 In one form, the distance from the level of the earth or soil around the building construction to the height of the first layer, is a minimum of about 100mm, typically 6241738_1 (GHMatters) P98381.AU.1 JMC - 20 greater than about 125mm, preferably greater than about 140mm. In one form, the protective barrier is a combined termite 5 resistant treatment, impermeable water membrane and damp proof course as well as having an indicator for determining the integrity or intactness of the first termite resistance coating, providing a barrier to pest infestation from termites, to the ingress of water or 10 moisture through the structure of the building panels or transmission of water or moisture through the external or internal surfaces of the building panel. Termites against which the protective barrier can be used 15 include the following species: - Coptotermes - Mastotermes - Schedorhinotermes - Nasutitermes 20 - Heterotermes - Microcetotermes - Amitermes Other pests include spiders and other invertebrates. 25 One form of one material, which can be used as the third layer or primer, is a rubber modified bitumen, such as for example, a material marketed under the name BLOCKAID which is a rubber modified bitumen mixed with natural plant 30 extracts. One form of the termite resistant material used as the first material in the first layer is Bifenthrin, such as 6241738_1 (GHMatters) P98381.AU.1 JMC - 21 for example in the form of a 2g/kg bifenthrin liquid product. One form of the bifenthrin is known as "Termiblock Termicide Sealant" available from Granitgard Pty Ltd. This product, once applied, will dry to form a 5 membrane and function as a termite resistant barrier layer. Any suitable material can be used as the damp proof course. 10 BRIEF DESCRIPTION OF DRAWINGS Forms of protective barriers will now be described by way of example to illustrate embodiments of the invention with 15 reference to the accompanying drawings in which: Figure 1 is a partial schematic cross sectional view of one form of the protective barrier showing the relationship of the two layers forming the protective 20 barrier to each other, to the building structure and to the surrounding soil or earth. Figure 2 is a schematic partial cross sectional view of another form of the protective barrier in situ. 25 DETAILED DESCRIPTION One form of the protective barrier and a method of forming the protective barrier will now be described with 30 reference to the drawings. Other forms which are not illustrated are possible. After a concrete slab, generally denoted as 10, has been 6241738_1 (GHMatters) P98381.AU.1 JMC - 22 poured and allowed to cure, including the formation of the edges 12 of slab 10 having rebates 14 upon which the walls of the building are formed, the walls of the building can be of any suitable construction. In one form, the rebate 5 has a width and a height arranged to extend perpendicularly to one another corresponding to the base 16 of the rebate and side wall 18 of the rebate. In one form, the wall includes an internal wall component 10 and an external wall component. In one form, the internal wall component is a suitable supporting wall in the form of a stud wall 20 made from a multitude of upright metal or timber studs 22. Stud wall 20 is formed on the upper surface 24 of slab 10 adjacent rebate 14 and secured in 15 place by suitable fasteners. One form of the external part of the wall is in the form of cladding, or similar external covering, such as for example, made from lightweight building panels 30, including autoclaved aerated concrete panels known as AAC panels, particularly 20 such panels provided by CSR Building Products Pty Ltd under the name HEBEL@. Lower edge 32 of each panel 30 is located in rebate 14 along outer edge 12 of concrete slab 10 with lower edge 32 of panel 30 resting on a bed of suitable bonding agent 34 located upon base surface 16 of 25 rebate 14 corresponding to the width of the rebate and securely attached by a suitable connector, such as top hat section 36, to slab 10, such as to vertical side wall 18 of rebate 14 corresponding to the height of the rebate. Additionally, building panels 30 are securely connected to 30 individual studs 22 of stud wall 20 by suitable fasteners, such as top hat connectors or sections 38, to secure the building panels to the supporting stud wall collectively. 6241738_1 (GHMatters) P98381.AU.1 JMC - 23 A slip layer is optionally provided between the bonding layer 34, and the base section 16 of rebate 14 of concrete slab 10 to allow for movement of the building panel with respect to slab 10. In one form, the slip layer is a damp 5 proof course (DPC) or similar. Other forms of the slip layer are possible, such as a moisture resistant or moisture proof membrane. After building panels 30 have been installed, nails or 10 other suitable components (not shown) are hammered or otherwise attached to the exterior of the panels to provide a guide in the form of a visible outline approximating soil line 40 of the building corresponding to the upper level of soil 42 which is located against the 15 outside of the building, such as by back filling when the construction of the building has been completed. In addition to the line of nails providing a guide as to the location and position of soil line 40, the line of nails also acts as a guide for location of one or more layers of 20 the protective barrier, such as for example, a guide for the location of the lower edge of the protective barrier, or a guide for the location of an indicator for providing an indication of the state of the protective barrier, particularly the state of the inner layer of the barrier. 25 A preliminary layer of suitable material (not shown), in the form of a primer layer, is applied optionally to the exterior of panels 30 at or towards their lower ends collectively 35. This optional layer is a primer layer. 30 In one form, the primer layer is a different layer to the first layer or the second layer. However, in other forms, the primer layer can be incorporated into the first layer. In one form, the material of the primer layer is Blockaid. 6241738_1 (GHMatters) P98381.AU.1 JMC - 24 A first layer of a first material of the protective barrier, typically in the form of a layer of termite resistant material, more typically containing or 5 incorporating a termicide or similar composition or compound, preferably a layer of Termiblock Termite Sealant or similar material, is applied to the exterior surface of building panels 30 and to the edges 12 of concrete slab 10, or to the surface of the primer layer if the primer is 10 optionally applied earlier to form a first part 52 of the first layer 50 and a second part 54 of the first layer. In one form, the termite resistant first material of the first layer 50, is Termiblock Termidice. 15 The first part 52 of the termite resistant material is applied to both building panel 30, and the second part 54 is applied to edge 12 of slab 10 so that the first part 52 is in contact with building panel 30 and/or the primer coating on the building panel and second part 54 of the 20 first material is in contact with slab 10 and/or the primer coating applied to edge 12 of slab 10. It is to be noted that the termite resistant coating Termiblock Termicide, forms a continuous layer extending between the lower end or edge 35 of building panel 30 and the outer 25 edge 12 of concrete slab 10. Preferably, the termite resistant layer extends to a minimum of about 100mm about the nail outline, typically greater than about 120mm, preferably, greater than about 140mm, most preferably to about 150mm above the nail line around the entire 30 perimeter of the building. The termite resistant component of the protective barrier is applied using a brush, roller, pump, trowel, spray, or in any other suitable or convenient manner to form the layer. 6241738_1 (GHMatters) P98381.AU.1 JMC - 25 Other additives for a variety of different purposes can be included in the first material for forming the first layer. 5 In the embodiment of Figure 1, the first layer is essentially linear layer arranged to extend vertically along the exterior of building panel 30 and edge 12 of slab 10. In the embodiment of Figure 2, the first layer 10 is stepped to have two substantially parallel spaced sections extending vertically in an intermediate section extending horizontally between the two spaced vertically sections. The first layer of both embodiments is substantially continuous. 15 After the layer of first material or termite resistant material has dried or cured, a second layer 60 of the second material forming the barrier, is applied to the building. In one form, the second material is a water 20 resistant or water impermeable material preventing transmission of water or moisture through the layer. In one form, second layer 60 is a water impervious membrane or damp proof course in the form of a render or other surface coating or treatment. One example of the surface 25 coating or treatment is HEBEL@ Render, which is applied to the external facing surfaces of the building panel. Layer 60 of the second water resistant coating is applied to the outer surface of building panel 30 so as to form a 30 first part 62 of this layer 60 which covers this surface and a second part 64 of layer 60 which covers the second part of existing termite resistant coating 52 and optional primer coating. The layer of water resistant coating 60 6241738_1 (GHMatters) P98381.AU.1 JMC - 26 extends upwardly along the external surface of building panel 30. Thus, first part 62 of second layer 60 protects AAC building panel 30 from water penetration and second part 64 of second layer 60 overlies termite resistant 5 coating 50 to form a protective barrier which is both termite resistant and water resistant. The layer of second material 60 is applied in any suitable manner, such as by brushing, roller, spraying, trowelling, pumping or the like. 10 An indicator 70 or similar is formed in the render coating 60 to provide an indication of the state of the first layer, such as for example, to provide an indication of whether coating 50 remains intact, to continue to provide 15 a termite resistant barrier or whether the coating has degraded to such an extent that the coating is no longer termite resistant. An indication of the layer being intact is provided by the appearance of the termite resistant layer in which the layer maintains its smooth 20 even finish without the appearance of delamination or discontinuities or irregularities in the surface, such as for example, in the form of bubbles, blisters, undulations, perforations or the like. 25 An indication of the failure of the layer is manifest by delamination of the layer and the appearance of surface discontinuities and irregularities in which bubbles, blisters, undulations, perforations and the like are visible indicative of moisture accumulating behind the 30 termite resistant layer. Indicator 70 can have any suitable form. One preferred form is a V-shaped notch or groove extending continuously 6241738_1 (GHMatters) P98381.AU.1 JMC - 27 around the perimeter of the building in which the profile of the V-shaped groove includes two inwardly inclined walls extending from the outer side of the second layer 60 towards first layer 50. 5 ADVANTAGES Advantages of one or other forms of the protective barrier and the methods of installing and/or forming the barrier 10 include one or other of the following. The overall protective barrier has more than a single function, namely the barrier provides protection against termite infestation, provides a barrier to water and 15 moisture transmission through the building and provides a damp proof course to prevent ingress and/or penetration of water. The protective barrier is able to be formed and/or applied 20 on site so is able to be modified to accommodate the terrain or topography of the ground and/or the style and design of the building. The protective barrier allows the lower ends of the AAC 25 building panels to be protected at all times and not remain in direct contact with the ground or surrounding soil. Although the lower end of the building panel may be located at a level lower than the soil line, the building panel is not in direct contact with the soil but rather 30 the protective barrier is located intermediate the building panel and the soil. By incorporating termite resistant treatments, coatings, 6241738_1 (GHMatters) P98381.AU.1 JMC - 28 layers and similar into the overall method of construction using AAC panels, there is less site complexity. Additionally, the system improves slab edge aesthetics and reduces installed costs of the building panels and 5 protective barrier. The AAC panels can be installed and the protective barrier formed without having to modify the quality of the slab edges thereby reducing site supervision issues and 10 remedial work by tradesmen called back to the site. 6241738_1 (GHMatters) P98381.AU.1 JMC