Apparatus for illuminating the interior of a building through a roof of the building, the apparatus comprising a light transmissive panel  13  and a light directing duct  12.  The panel  13  has an upper surface which is substantially identical in shape to an upper surface of a roof covering and lies in the plane of the said covering. The light directing duct  12  directs light from the panel  13  into the interior of the building. 
     The invention also relates to apparatus for venting the interior of a building. The apparatus comprises a venting panel  32  having at least one venting channel  44,  and having an upper surface which is substantially identical in shape to, and lies in the plane of an outer covering of the building. The interior of the building is vented through the panel  32.

This invention relates to apparatus for illuminating and/or venting the interior of a building and particularly, although not exclusively, relates to skylights and/or roof vents. 
     BACKGROUND TO THE INVENTION 
     When domestic or commercial roof spaces are used as living accommodation, storage or office space, it is preferable that they are at least partially lit by natural light. Sometimes this is achieved by fitting Velux (registered trade mark) or Dormer windows. Although modern Velux and Dormer windows are functional and attractive, planning permission for such structures on a roof is sometimes refused, or they are considered undesirable by the owner of the building. In such circumstances, it is known to provide a skylight comprising a light reflective tube which passes through the roof and projects above the level of the roof. The tube is capped by a light transmissive cover which projects still further above the surface of the roof. The whole assembly is unnecessarily cumbersome and unsightly. 
     STATEMENTS OF INVENTION 
     According to a first aspect of the present invention there is provided apparatus for illuminating the interior of a building through a roof of the building, the apparatus comprising a light transmissive panel which has an upper surface which is substantially identical in shape to an upper surface of a roof covering and which lies in the plane of the said covering, and a light directing duct which directs light from the panel into the interior of the building. 
     Preferably, the light directing duct is fitted to an underside of the panel. Most preferably the light directing duct is sealed to an underside of the panel. For example it may be attached permanently with adhesive or a sealant and/or may be sealed with a resilient gasket. 
     Preferably, the upper surface of the panel is flush with an upper surface of the covering. 
     Preferably, the covering comprises roof tiles, shingles, slates or roofing sheets and the panel matches the contour and spacing of one or more roof tiles, shingles, slates or roofing sheets. 
     Preferably, the panel comprises a first light transmissive portion which is aligned with the light directing duct and an opaque portion. Preferably, the opaque portion is coloured and/or textured to match the roof covering. 
     Preferably, the duct passes through an underlay layer of the roof. The underlay layer may be sealed to an outer surface of the duct. For example, it may be sealed with a resilient gasket. 
     Preferably, the panel further comprises an air vent for allowing air from outside the roof to circulate through the duct. Preferably, an upper section of the duct includes apertures which allow the air to pass into and out of the duct. 
     Preferably, a lower end of the duct is provided with a light transmissive cover. Preferably, at least part of the panel and/or the cover are transparent or translucent. Preferably, the panel and/or the cover are made from a plastics material such as polycarbonate. 
     It is well known that the temperature difference between the outside of a roof and the roof space beneath the roof can cause a build up of condensation within the roof space. This problem can be alleviated by venting the roof, so that fresh outside air flows across the roof space, thereby reducing the temperature within the roof space and reducing the humidity. It is known to vent roofs through vents provided under the eaves or above the weather boarding. This can provide some limited through flow of air, but the venting is greatly improved if vents are also provided along the ridge line of the roof. Conventional ridge vents project above the level of the roof and are unsightly. 
     According to a second aspect of the present invention, there is provided apparatus for venting the interior of a building, the apparatus comprising a venting panel having at least one venting channel, and having an upper surface which is substantially identical in shape to, and lies in the plane of, an outer covering of the building, the interior of the building being vented through the panel. 
     Preferably, the outer covering is a roof covering of the building such as tiles, shingles, slates or roofing sheets. 
     The venting channel may comprise a flow passage formed in or attached to the venting panel. 
     Preferably, the venting channel comprises an inlet at an edge of the panel and a plurality of air directing fins associated with the inlet. Preferably, a portion of at least one of the fins is offset relative to the inlet or is curved, to prevent rainwater entering the inlet. At least one of the fins may have a corrugated profile, and may extend in a direction substantially perpendicular to the inlet. 
     Preferably, a duct is provided which is in fluid communication with the channel formed in the roof tile, the duct passing into the interior of the building. 
     Preferably a fan is provided which is adapted to assist the flow of air through the panel and/or the duct. 
     Various objects and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the preferred embodiments, when read in light of the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a cross section through a first embodiment of skylight; 
         FIG. 2  is a top view of the skylight of  FIG. 1 ; 
         FIG. 3  is a perspective view of a large skylight; 
         FIG. 4  is a perspective view of multiple skylights fitted to a single light transmissive panel; 
         FIG. 5  is a cross section through a two part skylight assembly; 
         FIG. 6  is a plan view of a corrugated polycarbonate panel fitted with a light directing duct in accordance with the present invention; 
         FIG. 7  is a cross section through the embodiment of  FIG. 6 ; 
         FIG. 8  is a cross section through a skylight integrally formed with an air vent; 
         FIG. 9  is a perspective view of an artificial roof tile in accordance with the embodiment of  FIG. 8 ; 
         FIG. 10  is a perspective view of an artificial roof tile combining the functions of skylight and roof vent; 
         FIG. 11   a  is a view on the lower end of an artificial roof tile showing a vent opening; 
         FIG. 11   b  is a cut-away plan view of the end of the roof tile illustrated in  FIG. 11   a;    
         FIG. 12   a  is a view on the lower end of an artificial roof tile showing a vent opening; and 
         FIG. 12   b  is a cut-away plan view of the end of the artificial roof tile of  FIG. 12   a.    
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       FIGS. 1 and 2  show a first embodiment of skylight  1  comprising a cylindrical housing  2  fitted into a cylindrical opening  4  formed in a tile  6 . The cylindrical housing  2  is provided with an annular flange  8  which sits in a recess  10  formed in an upper surface of the tile  6  and prevents the cylindrical housing  2  slipping through the tile  6  in service. The cylindrical housing  2  and annular flange  8  are sealed to the tile  6  by means of adhesive, sealant or a sealing gasket arrangement (not shown) so that the joint between the cylindrical housing  2  and tile  6  is weatherproof. 
     The cylindrical housing  2  projects from the bottom of the tile  6  and is connected to a cylindrical light directing duct  12 . In the illustrated embodiment, and the cylindrical housing  2  is closely received within an end of the light directing duct  12 . The joint between the cylindrical housing  2  and light directing duct  12  is sealed by flexible sealant. However, the cylindrical housing  2  and light directing duct  12  may be of any desired shape and may be interconnected in any conventional manner. For example, the external diameter of the light directing duct  12  may be smaller than the internal diameter of the cylindrical housing  2  so that the light directing duct  12  is received within the cylindrical housing  2 . Such an arrangement would be inherently more weatherproof, since rainwater could not easily penetrate the gap between the cylindrical housing  2  and light directing duct  12 . 
     The upper end of the cylindrical housing  2  is sealed off by a light transmissive element  14  which forms, with the tile  6 , a light transmissive panel  13 . The opposite end of the light directing duct  12  is closed off by a light transmissive cover  16 . Furthermore, the inside surface  17  of the light directing duct  12  and/or the cylindrical housing  2  is coated with light reflecting material, such is used in a conventional lamp reflector. 
     The light transmissive element  14  and light transmissive cover  16  may be formed from any transparent or translucent material, such as Perspex or polycarbonate. Furthermore, the tile  6  may be replaced with an artificial tile so that the cylindrical housing  2  and tile  6  may be moulded together as an integral unit. Indeed, if the artificial tile  6  is made of light transmissive material, such as Perspex or polycarbonate, the cylindrical housing  2 , tile  6  and light transmissive element  14  can be integrally moulded together to form the light transmissive panel  13 . The portion of the artificial tile  6  which does not need to be light transmissive can be opaqued by means of painting or the addition of a surface finish, so that it matches the surrounding roof tiles. 
     In an alternative embodiment (not shown) the cylindrical housing  2 , light directing duct  12 , light transmissive element  14  and light transmissive cover  16  could be formed together as a sealed evacuated or gas filed unit. In such a sealed arrangement, condensation within the unit would not be a problem. However, in the embodiment of  FIGS. 1 and 2 , in which the cylindrical housing  2  is separate from the light directing duct  12 , it is preferable to include vent holes  18  which are open to the ambient air circulating beneath the tile  6 . The vent holes allow the ambient air to circulate through the space between the light transmissive element  14  and light transmissive cover  16  and prevent a build up of condensation within the unit. 
     The skylight  1  is attached to a roof by removing a section of roof tiles  23  to gain access to an underlay layer  20 . A hole is formed through the underlay layer  20  through which is fitted the light directing duct  12 . The duct  12  is sealed to the underlay layer  20  by means of a gasket  22 . The tile  6  is then lowered into position, such that the cylindrical housing  2  fits within the light directing duct  12 , and the gap between the two is sealed with a flexible sealant. Finally, the surrounding tiles  23  of the roof are made good. 
     As the skylight is located within a tile or artificial tile, when installed, and does not project above the upper surface of the tile the surface profile of the roof is maintained and all that is visible from the outside of the roof is the light transmissive element  14 . 
       FIG. 3  shows an alternative arrangement in which a single large light transmissive element  14  is fitted within a light transmissive panel  13  which is shaped to simulate four separate roof tiles, although it is integrally moulded as a single element. This is achieved by moulding into the panel  13  a step  22  to simulate the joint between upper and lower tiles and a groove  24  to simulate the gap between tiles laid side by side. 
       FIG. 4  shows a further embodiment in which a single integrally formed light transmissive panel  13  is moulded to simulate four separate tiles and includes four individual light transmissive elements  14 . The embodiments illustrated in  FIGS. 3 and 4  increase the amount of light which is directed into a space beneath the roof for the minimal additional effort in fitting the skylight. 
       FIG. 5  shows an alternative embodiment of skylight in which the light transmissive element  14 , the cylindrical housing  2  and the annular flange  8  are integrally formed together from light transmissive material and are inserted into a real or artificial tile  6  to form the light transmissive panel  13 . As in the embodiment of  FIGS. 1 and 2 , vent holes  18  are formed in the cylindrical housing  2  and the base of the cylindrical housing  2  is adapted to receive a light directing duct  12 . 
       FIGS. 6 and 7  show a further embodiment of skylight  1  in which the light transmissive panel  13  is formed by the roof covering itself. More specifically, the light transmissive panel  13  comprises a conventional corrugated polycarbonate roofing panel  26  to which the cylindrical housing  2  is fitted by means of adhesive or sealant applied to the flange  8 . As in the previous embodiments, a separate light directing duct  12  is connected to the cylindrical housing  2 , but in this embodiment it is received within the cylindrical housing  2 . 
     In order to ensure an adequate seal between the roofing panel  26  and the cylindrical housing  2  the upper edge of the cylindrical housing  2  is shaped to accommodate the corrugations of the roofing panel  26 . 
       FIGS. 8 to 12  show a roof vent  30  in accordance with a second aspect of the present invention. The roof vent comprises a panel  32  which may be opaque ( FIG. 9 ) or wholly or partially light transmissive ( FIG. 10 ), and has an upper surface which is substantially identical in shape to, and lies in the plane of an outer covering of a roof. 
     Referring specifically to  FIGS. 8 and 10 , the panel  32  is formed from plastics material and is moulded in the shape of a conventional roof tile on its upper surface and in the regions  34 ,  36  which are adapted to engage with other tiles on the roof. However, the underside of the panel  32  at its lower edge  38  is formed with a series of fins or baffles  40 . The baffles  40  project at right angles from the underside of the panel  32  and extend downwards as far as an underlying tile  42 , so that vent channels  44  are defined between respective pairs of baffles  40 . 
     In the  FIG. 8  embodiment, the panel  32  is formed entirely from polycarbonate. The upper surface of the panel  32  is coated in the regions  44 ,  46 , so that these regions are opaque and substantially match the appearance of neighbouring tiles on the roof. The circular portion of the upper surface of the panel  32  between the opaque portions  44 ,  46  is left transparent and acts as a light transmitting element  48 . Beneath the light transmitting element  48  is fitted a cylindrical housing  50  which is sealed to the panel  32  by means of an annular flange  52 . A cylindrical light directing duct  54  is closely received within the cylindrical housing  50  and is held in position by adhesive or sealant. 
     Vent holes  56  are formed through the cylindrical housing  50  and light directing duct  54  and a vent passage  57  is formed in the panel  32  between the baffles  40  and the cylindrical housing  50 . The interior of the light directing duct  54  is held in fluid communication with the vent channels  44  formed in the underside of the panel  32  via the vent holes  56  and the vent passage  57 . 
     If the lower end of the light directing duct  54  is closed by a transparent or translucent cover, the vents merely operate to prevent condensation within the light directing duct  54 . However, if the lower end of the light directing duct  54  is left open, or additional vent holes are provided at a lower end of the light directing duct  54 , ambient air is able to pass from the vent channels  42  into the roof space, via the vent holes  56  and the light directing duct  54 . Thus, vent panel  32  can be used either with a skylight assembly, or on its own as a means of venting a roof or loft space. 
       FIG. 11  shows an alternative embodiment in which the lower end  38  of the panel  32  is formed as a hollow tube having an upper wall  58  and a lower wall  60 , which are spaced apart by a plurality of staggered rows of posts  62 . The upper wall  58 , lower wall  60  and posts  62  define a tortuous flow path P for air entering the panel  32 , so that rain is unable to find a direct path and is prevented from penetrating beyond the first few rows of posts  62  of the panel  32 . 
       FIGS. 12   a  and  12   b  show a further embodiment in which the lower end  38  of the panel  32  is provided with an upper wall  58  and a lower wall  60  spaced apart by baffles  64  which are corrugated in cross section. These baffles  64  act in the same way as the posts  62 , since they force air entering the panel  32  to follow a tortuous path P which prevents the ingress of rain. 
     In accordance with the provisions of the patent statutes, the principle and mode of operation of this invention have been explained and illustrated in its preferred embodiment. However, it must be understood that this invention may be practiced otherwise than as specifically explained and illustrated without departing from its spirit or scope.