Patent Publication Number: US-2010122506-A1

Title: Fastening member and external wall construction structure

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a fastening member used for fastening exterior wall boards to a structural building frame, and to an external wall construction structure using the fastening member. 
     2. Description of the Related Art 
     As illustrated in  FIG. 16 , exterior wall boards include exterior wall boards A having shiplap portions at least at the upper edge and the lower edge. To construct the exterior wall of a building with exterior wall boards A, fastening members are used to fasten a plurality of such exterior wall boards to the building frame of the building in a staggered joint layout (for instance, as disclosed in Japanese Patent Application Laid-open No. 2002-371689).  FIG. 17  illustrates a fastening member disclosed in Japanese Patent Application Laid-open No. 2002-371689. The fastening member, which is formed by bending a steel sheet, comprises a base plate portion that abuts the back surface of exterior wall when the board is fastened; a central horizontal raised portion that is elected in the horizontal direction, frontward from the base plate portion: a downwardly bent portion bent downwards from the front end of the central horizontal raised portion; upwardly bent portions, provided at the left and right of the downwardly bent portion, and bent obliquely upwards from the front end of the central horizontal raised portion; front plate portions bent downwards from the upper end of the upwardly bent portions; bearing portions that are erected in the horizontal direction, at the left and right of the central horizontal raised portion, frontward from the base plate portion; upper-board locking portions bent upwards from the front end of the bearing portions; lower-board locking portions bent downwards from the front end of the bearing portions; and connection portions that connect, in the vertical direction, the leading ends of the upper-board locking portions and the leading ends of the lower-board locking portions; wherein an elastic material is provided at the left and right ends of the central horizontal raised portion, the top surfaces of the upwardly bent portions and the front surfaces of the front plate portions. 
     During fixing of the fastening member to a building frame, a bent upper leg and the leading end of a bent lower leg of the base plate portion are fixed to the building frame. To put up the exterior wall boards, these are fastened in such a manner that the shiplap portions of the lower edges of the exterior wall boards above the fastening member are locked on the bearing portions and the upper-board locking portions of the fastening member, with the back surface of the exterior wall boards abutting the base plate portion of the fastening member. The exterior wall board below the fastening member, meanwhile, is fastened in such a manner that the shiplap portion of the upper edge of the exterior wall board is locked on the central horizontal raised portion, the downwardly bent portion, the bearing portions and the lower-board locking portion, with the back surface of the exterior wall board abutting the base plate portion. 
     In the above-described fastening member, moreover, an elastic material is provided at the left and right ends of the central horizontal raised portion, the top surfaces of the upwardly bent portions and the front surfaces of the front plate portions. As a result, when the fastening member is disposed at the lower end of a vertical joint, rainwater or the like trickling down the vertical joint can be caught by the central horizontal raised portion between the left and right elastic materials, so that the water can be arrested by the elastic material and drained towards the front of the exterior wall by way of the downwardly bent portion. 
     Japanese Patent Application Laid-open No. 2002-371689 discloses also a fastening stopper comprising a base plate portion that abuts the back surface of the exterior wall board; a bearing portion that is erected in the horizontal direction at the front of the base plate portion; an upper-board locking portion bent upwards from the front end of the bearing portion; a lower-board locking portion bent downwards from the front end of the bearing portion; and a vertical raised portion that is erected in the vertical direction, from the front of the base plate portion, at a position below that of the bearing portion.  FIG. 18  illustrates such a fastening stopper. During construction of the exterior wall, the fastening stopper is fixed to the backing material in such a manner that the base plate portion of the fastening stopper abuts the back surface of the exterior wall board, the upper sides of the exterior wall boards that are disposed below the fastening stopper are locked on the lower-board locking portion of the fastening stopper, the lower side of the exterior wall board disposed above the fastening stopper rests on the bearing portion of the fastening stopper and is locked on the upper-board locking portion, and the side end faces of the exterior wall boards below the fastening stopper abut the vertical raised portion. 
     The vertical raised portion of the fastening stopper allows preventing the exterior wall boards positioned below the fastening stopper from shifting to the left or right. 
     In the external wall construction structure of Japanese Patent Application Laid-open No. 2002-371689, however, the shiplap portion of the lower edge of the exterior wall board disposed above the fastening stopper must abut reliably the elastic material of the fastening member so that no gap is left in between, in order to reliably prevent rainwater or the like from intruding into the exterior wall. However, there are limits to the precision with which the exterior wall boards are put up, and therefore it is difficult to avoid completely the presence of gaps between the exterior wall boards and the elastic material in such an external wall construction structure. Moreover, the elastic material is, for instance, a rubber foam material comprising ethylene rubber, EPDM (ethylene-propylene rubber) or the like, or a synthetic resin foam material such as polyethylene. As a result, elasticity may become impaired and gaps may grow in size as time goes by. 
     Although the fastening stopper of Japanese Patent Application Laid-open No. 2002-371689 allows preventing left-right shifting of the exterior wall boards that are disposed below the fastening stopper, the latter is ineffective against contraction of the exterior wall boards themselves or against distortion of the entire structure onto which the exterior wall boards are mounted, so that gaps may form at seams between exterior wall boards. When gaps form at seams between exterior wall boards, the central horizontal raised portion and the downwardly bent portion of the fastening member become exposed at the site where the shiplap portions of the three exterior wall boards meet to form an inverted T-joint. Although the gaps at seams between exterior wall boards are in the shadow, the central horizontal raised portion and the downwardly bent portion have ordinarily a metallic hue, and are thus easily noticeable. 
     Moreover, the uncovered central horizontal raised portion and the downwardly bent portion become then exposed to rain, sunlight and the like at all times, which may result in corrosion and deterioration of the metal sheet. 
     SUMMARY OF THE INVENTION 
     In order to solve the above problems of conventional external wall construction structures, it is an object of the present invention to provide a fastening member and an external wall construction structure that do not corrode or deteriorate easily, in which the fastening member abuts reliably the shiplap portions of the lower edges of exterior wall boards that are put up above the fastening member, in which the abutting state of the fastening member with the shiplap portions of the lower edges of the exterior wall boards is preserved also after construction, and in which no part of the fastening member is noticeable, even when exposed through gaps between exterior wall boards. 
     According to a first aspect of the present invention is a fastening member for an exterior wall board, comprising: a left support portion and a right support portion provided at left and right sides of the fastening member, and abutting a back surface of the exterior wall board when the board is fastened, the fastening member further comprising, at a region flanked by the left support portion and the right support portion: a base plate portion constituting a mount portion to be fixed to a building frame; a central support portion that abuts the back surface of the exterior wall board when the board is fastened; a central horizontal raised portion that is erected, in a horizontal direction, frontward from the lower end of the central support portion; a downwardly bent portion that is bent downwards from the front end of the central horizontal raised portion; upwardly bent portions that are provided at the left and right of the downwardly bent portion, and are bent obliquely upwards from the front end of the central horizontal raised portion; front plate portions that are bent downwards from the upper end of the upwardly bent portions; bearing portions that are erected in the horizontal direction, at the left and right of the central horizontal raised portion, frontward from the central support portion; upper-board locking portions bent upwards from the front end of the bearing portions; and 
     a lower support portion that abuts the back surface of the exterior wall board when the board is fastened, the left support portion, the right support portion, the lower support portion and the central support portion of the fastening member being formed contiguously to each other through drawing one steel sheet; the base plate portion being formed through depressing part of the upper region of the steel sheet towards the back surface thereof; the central horizontal raised portion, the downwardly bent portion, the upwardly bent portions, the front plate portions, the bearing portions and the upper-board locking portions being formed through cutting and raising part of the lower region of the steel sheet towards the front surface thereof; a waterproof material being provided at the left and right ends of the central horizontal raised portion, the top surfaces of the upwardly bent portions and the front surfaces of the front plate portions; and the waterproof material being made of bentonite. 
     In the fastening member of the present invention, moreover, the waterproof material provided at the left and right ends of the central horizontal raised portion, the top surfaces of the upwardly bent portions and the front surfaces of the front plate portions may comprise bentonite alone, or may comprise bentonite plus a rubber foam material comprising ethylene rubber such as EPDM (ethylene-propylene rubber), or a synthetic resin foam material such as polyethylene. When using concomitantly bentonite and EPDM or the like, the waterproof material may be a molded product of a laminate of bentonite and EPDM or the like, or may be a molded product of a mixture of bentonite and EPDM or the like. 
     As the steel sheet there can be used a Galvalume steel sheet, a galtite steel sheet, an aluminum steel sheet, a stainless steel sheet, an alloy plated steel sheet, a galvanized plate, a copper sheet or the like. 
     The fastening member of the present invention can be reliably fixed to a building frame by way of the base plate portion that constitutes amount portion to be fixed to the building frame. The left support portion, the right support portion, the central support portion and the lower support portion allow the exterior wall board to be fixed stably through abutting of the fastening member against the back surface of the exterior wall board when the board is fastened. The central horizontal raised portion and the downwardly bent portion allow locking the shiplap portion of the upper edge of the exterior wall board that is disposed below the fastening member, while the bearing portions and the upper-board locking portions allow locking the shiplap portions of the lower edges of the exterior wall boards that are disposed above the fastening member. 
     Even if small gaps exist between the fastening member and the shiplap portions of the lower edges of the exterior wall boards that are put up above the fastening member, the bentonite that is provided at the left and right ends of the central horizontal raised portion, the top surfaces of the upwardly bent portions and the front surfaces of the front plate portions of the fastening member swells on account of the first rainwater that intrudes. The swollen bentonite fills up the gaps between the shiplap portions of the lower edges of the exterior wall boards and the fastening member. As a result, the shiplap portions of the lower edges of the exterior wall boards abut the fastening member reliably, and rainwater or the like trickling down the vertical joint can be caught and reliably arrested by the central horizontal raised portion, to be drained towards the front of the exterior wall by way of the downwardly bent portion. When the waterproof material contains an elastic material such as EPDM or the like, the elastic material may deteriorate over time giving rise to small gaps between the fastening member and the shiplap portions of the lower edges of the exterior wall boards. However, the waterproof material comprises bentonite, and hence the bentonite swells on account of intruding water and fills up the formed gaps, whereby rainwater or the like trickling down the vertical joint can be arrested and drained over long periods of time. 
     Further, the fastening member is formed out of a steel sheet and has a simple shape. As a result, the fastening member does not deform readily even under the action of external forces, and thus the exterior wall boards can be reliably fixed over long periods of time. The fastening member, moreover, can be manufactured easily and with good productivity, with manufacturing costs kept low. 
     According to a second aspect of the present invention is the fastening member according to the first aspect, wherein the waterproof material is made of bentonite and an elastic material. The elastic material is a material having elasticity, for instance a rubber foam material comprising ethylene rubber, EPDM (ethylene-propylene rubber) or the like, or a synthetic resin foam material such as polyethylene. The waterproof material may be a molded product of a laminate of bentonite and the elastic material, or a molded product of a mixture of bentonite and the elastic material. 
     In the present invention, the elastic waterproof material comprising bentonite and the elastic material is provided at the left and right ends of the central horizontal raised portion, the top surfaces of the upwardly bent portions and the front surfaces of the front plate portions. As a result, the elastic waterproof material allows further filling up the space between the fastening member and the shiplap portions of the lower edges of the exterior wall boards that are disposed above the fastening member. Even if small gaps form between the fastening member and the shiplap portions of the lowers edges of the exterior wall boards when the latter are put up, the gaps are filled up by the bentonite, which swells on account of the first rainwater that intrudes. Thus, the shiplap portions of the lower edges of the exterior wall boards abut the fastening member reliably, and rainwater or the like trickling down the vertical joint can be caught and reliably arrested by the central horizontal raised portion, to be drained towards the front of the exterior wall by way of the downwardly bent portion. Likewise, even if small gaps form between the fastening member and the shiplap portions of the lower edges of the exterior wall boards as the elastic material deteriorates over time, the formed gaps are filled up by the bentonite contained in the waterproof material and that swells on account of the first rainwater that intrudes. As a result, rainwater or the like trickling down the vertical joint can be arrested and drained over long periods of time. 
     According to a third aspect of the present invention is the fastening member according to the first or second aspect, wherein the downwardly bent portion is coated in a blackish color or has a blackish tape adhered thereto. This blackish color maybe black, dark brown, dark grey or the like. The coating may be an acrylic resin coating, a urethane resin coating, a silicone resin coating, an epoxy resin coating or the like. 
     In the present invention, the downwardly bent portion of the fastening member remains unnoticed, thanks to its blackish color, even when gaps form at the seams between exterior wall boards due to contraction of the exterior wall boards themselves or due to distortion of the entire structure to which the exterior wall boards are mounted. Also, the downwardly bent portion is coated or has a tape adhered thereto. The downwardly bent portion is therefore protected by the tape or the coating, and is thus less susceptible to corrosion and deterioration. 
     According to a fourth aspect of the present invention is the fastening member according to the first, second or third aspect, wherein the central horizontal raised portion is coated in a blackish color or has a blackish tape adhered thereto. This blackish color may be black, dark brown, dark grey or the like. The coating may be an acrylic resin coating, a urethane resin coating, a silicone resin coating, an epoxy resin coating or the like. 
     In the present invention, the central horizontal raised portion of the fastening member remains unnoticed, thanks to its blackish color, even when gaps form at the seams between exterior wall boards due to contraction of the exterior wall boards themselves or due to distortion of the entire structure to which the exterior wall boards are mounted. Also, the central horizontal raised portion is coated or has a tape adhered thereto. The central horizontal raised portion is therefore protected by the tape or the coating, and is thus less susceptible to corrosion and deterioration. 
     According to a fifth aspect of the present invention is an external wall construction structure, comprising: a plurality of fastening members according to the first, second, third or fourth aspect mounted in multiple rows such that a base plate portion abuts a mounting surface of a building frame; an exterior wall board having shiplap portions at least at an upper edge and a lower edge, and fastened in such a manner that the back surface thereof abuts the left support portion, right support portion, central support portion and lower support portion of the fastening member; the shiplap portions of the upper edges of the exterior wall board are locked on the central horizontal raised portion and the downwardly bent portion of the fastening member at an upper position; the shiplap portions of the lower edge of the exterior wall board are locked on the bearing portions and the upper-board locking portions of the fastening member at a lower position; and the shiplap portions of the lower edge of the exterior wall boards abut the waterproof material. 
     The external wall construction structure of the present invention allows exterior wall boards to be reliably locked and fixed. Also, a waterproof material comprising bentonite is provided at the left and right ends of the central horizontal raised portion, the top surfaces of the upwardly bent portions and the front surfaces of the front plate portions of the fastening member that is mounted, so that the shiplap portions of the lower edges of the exterior wall boards are locked abutting the waterproof material. As a result, even if small gaps exist between the fastening member and the shiplap portions of the lowers edges of the exterior wall boards, the gaps are filled up by the bentonite in the waterproof material, which swells on account of the first rainwater that intrudes. Thus, the shiplap portions of the lower edges of the exterior wall boards abut the fastening member reliably, and rainwater or the like trickling down the vertical joint can be caught and reliably arrested by the central horizontal raised portion, to be drained towards the front of the exterior wall by way of the downwardly bent portion. Likewise, even if small gaps form between the fastening member and the shiplap portions of the lower edges of the exterior wall boards through deterioration over time of the elastic material, such as EPDM, contained in the waterproof material, the formed gaps are filled up by the bentonite contained in the waterproof material and that swells on account of the first rainwater that intrudes. As a result, rainwater or the like trickling down the vertical joint can be arrested and drained over long periods of time. 
     When using a fastening member in which the downwardly bent portion and/or the central horizontal raised portion are coated in a blackish color or have a blackish tape adhered thereto, the downwardly bent portion and/or the central horizontal raised portion in the external wall construction structure are less likely to corrode or deteriorate. 
     The present invention succeeds thus in providing a fastening member and an external wall construction structure that do not corrode or deteriorate easily, in which the shiplap portions of the lower edges of the exterior wall boards that are put up above the fastening member abut the fastening member reliably, in which the abutting state of the fastening member with the shiplap portions of the lower edges of the exterior wall boards is preserved also after construction, and in which no part of the fastening member is noticeable, even when exposed through gaps at the seams between exterior wall boards. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram illustrating an embodiment of a fastening member according to the present invention; 
         FIG. 2  is a working diagram illustrating an embodiment of an external wall construction structure according to the present invention, in which the fastening member illustrated in  FIG. 1  is fixed to a building frame of a building; 
         FIG. 3  is a diagram illustrating an external wall comprising multiples rows of the external wall construction structures illustrated in  FIG. 2 ; 
         FIG. 4  is a diagram illustrating another embodiment of a fastening member according to the present invention; 
         FIG. 5  is a working diagram illustrating another embodiment of an external wall construction structure according to the present invention, in which the fastening member illustrated in  FIG. 4  is fixed to a building frame of a building; 
         FIG. 6  is a diagram illustrating an external wall comprising multiples rows of the external wall construction structures illustrated in  FIG. 5 ; 
         FIG. 7  is a diagram illustrating yet another embodiment of a fastening member according to the present invention; 
         FIG. 8  is a working diagram illustrating yet another embodiment of an external wall construction structure according to the present invention, in which the fastening member illustrated in  FIG. 7  is fixed to a building frame of a building; 
         FIG. 9  is a diagram illustrating an external wall comprising multiples rows of the external wall construction structures illustrated in  FIG. 8 ; 
         FIG. 10  is a diagram illustrating yet another embodiment of a fastening member according to the present invention; 
         FIG. 11  is a working diagram illustrating yet another embodiment of an external wall construction structure according to the present invention, in which the fastening member illustrated in  FIG. 10  is fixed to a building frame of a building; 
         FIG. 12  is a diagram illustrating an external wall comprising multiples rows of the external wall construction structures illustrated in  FIG. 11 ; 
         FIG. 13  is a diagram illustrating yet another embodiment of a fastening member according to the present invention; 
         FIG. 14  is a working diagram illustrating yet another embodiment of an external wall construction structure according to the present invention, in which the fastening member illustrated in  FIG. 13  is fixed to a building frame of a building; 
         FIG. 15  is a diagram illustrating an external wall comprising multiples rows of the external wall construction structures illustrated in  FIG. 14 ; 
         FIG. 16  is a diagram illustrating an exterior wall board having shiplap portions on the upper edge and the lower edge; 
         FIG. 17  is a diagram illustrating a conventional fastening member; and 
         FIG. 18  is a diagram illustrating a conventional fastening stopper. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Preferred embodiments of the present invention are explained in detail next with reference to  FIGS. 1 to 15 . 
     Embodiment 1 
       FIG. 1  is a diagram illustrating an embodiment of a fastening member according to the present invention. 
     A fastening member B 1  illustrated in  FIG. 1  is manufactured out of a Galvalume steel sheet having a thickness of 0.8 mm. At the left and right sides, the fastening member B 1  comprises a left support portion  8  and a right support portion  9  that abut each the back surface of an exterior wall board when the board is fastened. 
     In the area flanked by the left support portion  8  and the right support portion  9 , the fastening member B 1  comprises a base plate portion  3  that constitutes a mount portion to be fixed to a building frame; a central support portion  10  that abuts the back surface of an exterior wall board when the board is fastened; a central horizontal raised portion  12   a  that is erected in a horizontal direction, frontward from the lower end of the central support portion  10 ; a downwardly bent portion  13   a  bent downwards from the front end of the central horizontal raised portion  12   a;  upwardly bent portions  14 , provided at the left and right of the downwardly bent portion  13   a,  and bent obliquely upwards from the front end of the central horizontal raised portion  12   a;  front plate portions  15  bent downwards from the upper end of the upwardly bent portions  14 ; bearing portions  16  that are erected in the horizontal direction, at the left and right of the central horizontal raised portion  12   a,  frontward from the central support portion  10 ; upper-board locking portions  17  bent upwards from the front end of the bearing portions  16 ; and a lower support portion  11  that abuts the back surface of an exterior wall board when the board is fastened. 
     The left support portion  8 , the right support portion  9 , the lower support portion  11  and the central support portion  10  are formed contiguously to each other through drawing of a steel sheet. The base plate portion  3  is formed through depressing part of the upper region of the steel sheet towards the back surface thereof. The central horizontal raised portion  12   a,  the downwardly bent portion  13   a,  the upwardly bent portions  14 , the front plate portions  15 , the bearing portions  16  and the upper-board locking portions  17  are formed through cutting and raising of part of the lower region of the steel sheet towards the front surface thereof. 
     The base plate portion  3  comprises a bulging portion  4 , nail openings  5 , screw holes  6  and ribs  7 . Flange portions  1  that extend flush with the base plate portion  3  are provided in the vicinity of the outward sides of the left support portion  8  and the right support portion  9 . Cutouts  2  are provided in the vicinity of the inward sides of the left support portion  8  and the right support portion  9 . The bulging portion  4  and the ribs  7  are likewise formed by drawing. 
     A waterproof material D 1  comprising bentonite is provided on the left and right ends of the central horizontal raised portion  12   a,  on the top surfaces of the upwardly bent portions  14 , and on the front surfaces of the front plate portions  15 . 
     By way of the base plate portion  3 , the fastening member B 1  can be reliably fixed to the building frame of the building by hammering nails through the nail openings  5  and/or driving screws through the screw holes  6 . The fastening member B 1  is fixed yet more thanks to the flange portions  1  that are provided flush with the base plate portion  3 . 
     By way of the left support portion  8 , the right support portion  9 , the central support portion  10  and the lower support portion  11 , an exterior wall board can be fixed stably through abutting of the fastening member B 1  against the back surface of the exterior wall board when the board is fastened. 
     The central horizontal raised portion  12   a  and the downwardly bent portion  13   a,  moreover, allow locking a shiplap portion of the upper edge of an exterior wall board that is disposed below the fastening member B 1 . Also, the bearing portions  16  and the upper-board locking portions  17  allow locking shiplap portions of the lower edges of exterior wall boards that are disposed above the fastening member B 1 . 
     With the cutouts  2  being provided in the vicinity of the inward sides of the left support portion  8  and the right support portion  9 , the cutouts  2  of the fastening member B 1  change temporarily to absorb wind pressure when substantial wind pressure acts on the fastened exterior wall boards after construction. Thereby, the cutouts  2  allow easing the load acting on the shiplap portions of exterior wall boards that are locked on the central horizontal raised portion  12   a,  the downwardly bent portion  13   a,  the bearing portions  16  and the upper-board locking portions  17 . A highly stable fastened state can be maintained as a result for long periods of time. 
     Even if small gaps exist between the fastening member B 1  and the shiplap portions of the lower edges of the exterior wall boards that are put up above the fastening member B 1 , the bentonite that is provided at the left and right ends of the central horizontal raised portion  12   a,  the top surfaces of the upwardly bent portions  14  and the front surfaces of the front plate portions  15  of the fastening member B 1 , swells on account of the first rainwater that intrudes. The swollen bentonite fills up the gaps between the shiplap portions of the lower edges of the exterior wall boards and the fastening member B 1 . The shiplap portions of the lower edges of the exterior wall boards can abut the fastening member B 1  reliably as a result, and rainwater or the like trickling down the vertical joint can be caught and reliably arrested by the central horizontal raised portion  12   a,  to be drained towards the front of the exterior wall by way of the downwardly bent portion  13   a.  Likewise, even if small gaps form between the shiplap portions of the lower edges of the exterior wall boards and the fastening member B 1  as a result of external forces applied to the exterior wall board and the fastening member B 1 , the formed gaps are filled up by the bentonite that swells on account of intruding rainwater. Therefore, rainwater or the like trickling down the vertical joint can be arrested and drained over long periods of time. 
     Further, the fastening member B 1  is formed out of a Galvalume steel sheet and has a simple shape. As a result, the fastening member B 1  does not deform readily even under the action of external forces, and thus the exterior wall board can be reliably fixed over long periods of time. The fastening member B 1 , moreover, can be manufactured easily and with good productivity, with manufacturing costs kept low. 
       FIG. 2  is a diagram illustrating an embodiment of an external wall construction structure according to the present invention, in which the fastening member illustrated in  FIG. 1  is fixed to the building frame of a building. 
     In the external wall construction structure illustrated in  FIG. 2 , an exterior wall board A having at least shiplap portions at the upper edge and the lower edge, as illustrated in  FIG. 16 , is fixed to a backing material F that is the building frame of the building, using screws E and the fastening member B 1  illustrated in  FIG. 1 . 
     In the present external wall construction structure, the fastening member B 1  illustrated in  FIG. 1  can be reliably fixed to the backing material F thanks to screws E that are driven through the screw holes  6 , with the base plate portion  3  and the flange portions  1  abutting the backing material F. 
     Likewise, the exterior wall boards A can be fixed stably thanks to the screws E that are driven through the screw holes  6 , with the left support portion  8 , the right support portion  9 , the central support portion  10  and the lower support portion  11  of the fastening member B 1  abutting the back surface of the exterior wall board A. 
     The exterior wall board A that is positioned below the fastening member B 1  can be reliably fixed thanks to the screws E that are driven through the screw holes  6 , with the central horizontal raised portion  12   a  and the downwardly bent portion  13   a  of the fastening member B 1  locking the shiplap portion of the upper edge of the exterior wall board A that is positioned below the fastening member B 1 . The exterior wall boards A that are positioned above the fastening member B 1  can be reliably fixed thanks to the screws E that are driven through the screw holes  6 , with the bearing portions  16  and the upper-board locking portions  17  of the fastening member B 1  locking the shiplap portions of the lower edges of the exterior wall boards A that are positioned above the fastening member B 1 . 
     The exterior wall boards A are fixed by way of the fastening member B 1  having the cutouts  2  in the vicinity of the inward sides of the left support portion  8  and the right support portion  9 . The cutouts  2  of the fastening member B 1  change temporarily to absorb thereby wind pressure when substantial wind pressure acts on the fastened exterior wall boards A after the latter have been put up. This allows, as a result, easing the load acting on the shiplap portions of the exterior wall boards A that are locked on the central horizontal raised portion  12   a,  the downwardly bent portion  13   a,  the bearing portions  16  and the upper-board locking portions  17 . A highly stable fastened state can be maintained as a result for long periods of time. 
     The shiplap portions of the lower edges of the exterior wall boards A that are positioned above the fastening member B 1  are locked, so as to abut the waterproof material D 1 , by the fastening member B 1  having the waterproof material D 1  that comprises bentonite and is provided at the left and right ends of the central horizontal raised portion  12   a,  the top surfaces of the upwardly bent portions  14  and the front surfaces of the front plate portions  15 . Therefore, even if small gaps exist between the fastening member B 1  and the shiplap portions of the lower edges of the exterior wall boards A, the gaps are filled up by the bentonite of the waterproof material D 1 , which swells on account of the first rainwater that intrudes. The shiplap portions of the lower edges of the exterior wall boards A abut thus reliably the fastening member B 1 , and rainwater and the like trickling down the vertical joint is caught and reliably arrested by the central horizontal raised portion  12   a,  to be drained towards the front of the exterior wall by way of the downwardly bent portion  13   a.  Likewise, even if small gaps form between the fastening member B 1  and the shiplap portions of the lower edges of the exterior wall boards A as a result of external forces applied to the exterior wall boards A and the fastening member B 1 , the gaps are filled up by the bentonite, which swells on account of the first rainwater that intrudes. As a result, rainwater or the like trickling down the vertical joint can be arrested and drained over long periods of time. 
     Although not shown in  FIG. 2 , another exterior wall board A is locked at the upper right position of the fastening member B 1 . Specifically, this other exterior wall board A is fixed by the fastening member B 1  in such a manner that the back surface of the exterior wall board A abuts the right support portion  9  and the central support portion  10  of the fastening member B 1 , while the shiplap portion of the lower edge of the exterior wall board A is locked on the bearing portion  16  and the upper-board locking portion  17 . 
       FIG. 3  is a diagram illustrating an external wall comprising multiples rows of the external wall construction structures illustrated in  FIG. 2 . 
     In  FIG. 3 , the exterior wall is formed of a plurality of exterior wall boards A that are fastened in a staggered layout to the building frame of a building by means of the fastening member B 1  illustrated in  FIG. 1  and the fastening stopper C illustrated in  FIG. 18 . 
     In  FIG. 3 , the construction structure illustrated in  FIG. 2  is used at sites where the shiplap portions of three exterior wall boards A meet to form an inverted T-joint, while the three exterior wall boards A are fixed by the fastening stopper C at sites where the shiplap portions of three exterior wall boards A meet to form a T-joint. As a result, the exterior wall boards A can be fixed stably over long periods of time. 
     The fastening member B 1  is fixed at the sites where the shiplap portions of three exterior wall boards A meet to form an inverted T-joint. Therefore, even if small gaps exist between the shiplap portions of the lower edges of the exterior wall boards A and the fastening member B 1 , the gaps are thus filled up by the bentonite of the waterproof material D 1 , which swells on account of the first rainwater that intrudes. The shiplap portions of the lower edges of the exterior wall boards A abut the fastening member B 1  reliably, and rainwater and the like trickling down the vertical joint is caught and reliably arrested by the central horizontal raised portion  12   a,  to be drained towards the front of the exterior wall by way of the downwardly bent portion  13   a.  Rainwater or the like trickling down the vertical joint can thus be arrested and drained over long periods of time. 
     Embodiment 2 
       FIG. 4  is a diagram illustrating another embodiment of a fastening member according to the present embodiment. 
     The fastening member B 2  illustrated in  FIG. 4  is identical to the fastening member B 1  illustrated in  FIG. 1  except that herein a waterproof material D 2  comprises bentonite and EPDM, and has elasticity. Specifically, the fastening member B 2  is also formed out of a Galvalume steel sheet, and comprises flange portions  1 , cutouts  2 , a base plate portion  3 , a bulging portion  4 , nail openings  5 , screw holes  6 , ribs  7 , a left support portion  8 , aright support portion  9 , a central support portion  10 , a lower support portion  11 , a central horizontal raised portion  12   a,  a downwardly bent portion  13   a,  upwardly bent portions  14 , front plate portions  15 , bearing portions  16  and upper-board locking portions  17 . The waterproof material D 2  is provided on the left and right ends of the central horizontal raised portion  12   a,  the top surfaces of the upwardly bent portions  14  and the front surfaces of the front plate portions  15 . 
     As is the case in the fastening member B 1  illustrated in  FIG. 1 , the fastening member B 2  as well can be fixed reliably to the building frame side of a building, the exterior wall boards can be fixed stably, there can be locked a shiplap portion of the upper edge of an exterior wall board disposed below the fastening member B 2 , there can be locked the shiplap portions of the lower edges of exterior wall boards disposed above the fastening member B 2 , the fastening member B 2  does not deform readily even under the action of external forces, the exterior wall boards can be reliably fixed over long periods of time, and the fastening member B 2  can be manufactured easily and with good productivity, with manufacturing costs kept low. 
     The elastic waterproof material D 2 , provided at the left and right ends of the central horizontal raised portion  12   a,  the top surfaces of the upwardly bent portions  14  and the front surfaces of the front plate portions  15 , allows the shiplap portions of the lower edges of the exterior wall boards that are put up above the fastening member B 2  to abut the fastening member B 2  reliably. The waterproof material D 2 , moreover, comprises bentonite. Hence, even if small gaps exist between the fastening member B 2  and the shiplap portions of the lower edges of the exterior wall boards that are put up above the fastening member B 2 , the bentonite that is provided at the left and right ends of the central horizontal raised portion  12   a,  the top surfaces of the upwardly bent portions  14  and the front surfaces of the front plate portions  15  of the fastening member B 2 , swells on account of the first rainwater that intrudes. The swollen bentonite fills up the gaps between the shiplap portions of the lower edges of the exterior wall boards and the fastening member B 2 . The shiplap portions of the lower edges of the exterior wall boards abut the fastening member B 2  reliably as a result, and rainwater and the like trickling down the vertical joint is caught and reliably arrested by the central horizontal raised portion  12   a,  to be drained towards the front of the exterior wall by way of the downwardly bent portion  13   a.  Likewise, even if small gaps form between the shiplap portions of the lower edges of the exterior wall boards and the fastening member B 2  as the EPDM deteriorates over time, the formed gaps are filled up by the bentonite contained in the waterproof material D 2  and that swells on account of intruding rainwater. As a result, rainwater or the like trickling down the vertical joint can be arrested and drained over long periods of time. 
       FIG. 5  is a diagram illustrating another example of an external wall construction structure according to the present invention, in which the fastening member illustrated in  FIG. 4  is fixed to the building frame of a building. 
     The fastening member B 2  illustrated in  FIG. 4  is identical to the fastening member B 1  illustrated in  FIG. 1  except that herein the waterproof material D 2  comprises bentonite and EPDM, and has elasticity. Therefore, the external wall construction structure illustrated in  FIG. 5  is identical to the external wall construction structure illustrated in  FIG. 2  except that herein the waterproof material D 2  comprises bentonite and EPDM, and has elasticity. Thus, in the external wall construction structure illustrated in  FIG. 5  as well, the fastening member B 2  can be reliably fixed to the backing material F thanks to screws E that are driven through the screw holes  6 , with the base plate portion  3  and the flange portions  1  abutting the backing material F. Likewise, the exterior wall boards A can be fixed stably thanks to the screws E that are driven through the screw holes  6 , with the left support portion  8 , the right support portion  9 , the central support portion  10  and the lower support portion  11  of the fastening member B 2  abutting the back surface of the exterior wall board A. The exterior wall board A that is positioned below the fastening member B 2  can be reliably fixed thanks to the screws E that are driven through the screw holes  6 , with the central horizontal raised portion  12   a  and the downwardly bent portion  13   a  of the fastening member B 2  locking the shiplap portion of the upper edge of the exterior wall board A that is positioned below the fastening member B 2 . The exterior wall boards A that are positioned above the fastening member B 2  can be reliably fixed thanks to the screws E that are driven through the screw holes  6 , with the bearing portions  16  and the upper-board locking portions  17  of the fastening member B 2  locking the shiplap portions of the lower edges of the exterior wall boards A that are positioned above the fastening member B 2 . The exterior wall boards A are fixed by way of the fastening member B 2  having the cutouts  2  in the vicinity of the inward sides of the left support portion  8  and the right support portion  9 . A highly stable fastened state can be maintained as a result for long periods of time. 
     The waterproof material D 2 , provided at the left and right ends of the central horizontal raised portion  12   a,  the top surfaces of the upwardly bent portions  14  and the front plate portions  15  of the fastening member B 2 , and comprising bentonite and EPDM, is fixed abutting the shiplap portions of the lower edges of the exterior wall boards A that are disposed above the fastening member B 2 . Therefore, even if small gaps exist between the shiplap portions of the lower edges of the exterior wall boards A and the fastening member B 2 , the gaps are thus filled up by the bentonite of the waterproof material D 2 , which swells on account of the first rainwater that intrudes. The shiplap portions of the lower edges of the exterior wall boards A abut the fastening member B 2  reliably, and rainwater and the like trickling down the vertical joint is caught and reliably arrested by the central horizontal raised portion  12   a,  to be drained towards the front of the exterior wall by way of the downwardly bent portion  13   a.  Likewise, even if small gaps form between the fastening member B 2  and the shiplap portions of the lower edges of the exterior wall boards A as the EPDM deteriorates over time, the formed gaps are filled up by the bentonite contained in the waterproof material D 2  and that swells on account of the first rainwater that intrudes. Therefore, rainwater or the like trickling down the vertical joint can be arrested and drained over long periods of time. 
     Although not shown in  FIG. 5 , another exterior wall board A is locked at the upper right position of the fastening member B 2 . Specifically, this other exterior wall board A is fixed by the fastening member B 2  in such a manner that the back surface of the exterior wall board A abuts the right support portion  9  and the central support portion  10  of the fastening member B 2 , while the shiplap portion of the lower edge of the exterior wall board A is locked on the bearing portion  16  and the upper-board locking portion  17 . 
       FIG. 6  is a diagram illustrating an external wall comprising multiples rows of the external wall construction structures illustrated in  FIG. 5 . 
     In  FIG. 6 , the exterior wall is formed of a plurality of exterior wall boards A that are fastened in a staggered layout to the building frame of a building by means of the fastening member B 2  illustrated in  FIG. 4  and the fastening stopper C illustrated in  FIG. 18 . The exterior wall illustrated in  FIG. 6  is identical to the exterior wall illustrated in  FIG. 3 , except that the fastening member B 1  of the exterior wall illustrated in  FIG. 3  is now the fastening member B 2 . 
     Therefore, the exterior wall boards A can be fixed stably over long periods of time. The fastening member B 2  is fixed at the sites where the shiplap portions of three exterior wall boards A meet to form an inverted T-joint. Therefore, even if small gaps exist between the fastening member B 2  and the shiplap portions of the lower edges of the exterior wall board A, the gaps are thus filled up by the bentonite of the waterproof material D 2 , which swells on account of the first rainwater that intrudes. As a result, rainwater and the like trickling down the vertical joint is caught and reliably arrested by the central horizontal raised portion  12   a,  to be drained towards the front of the exterior wall by way of the downwardly bent portion  13   a.  Likewise, even if small gaps form between the fastening member B 2  and the shiplap portions of the lower edges of the exterior wall board A as the EPDM deteriorates over time, the formed gaps are filled up by the bentonite contained in the waterproof material D 2  and that swells on account of the first rainwater that intrudes. Therefore, rainwater or the like trickling down the vertical joint can be arrested and drained over long periods of time. 
     Embodiment 3 
       FIG. 7  is a diagram illustrating yet another embodiment of a fastening member according to the present embodiment. 
     The fastening member B 3  illustrated in  FIG. 7  is identical to the fastening member B 1  illustrated in  FIG. 1 , except that herein a downwardly bent portion  13   b  has a black tape adhered thereto. Specifically, the fastening member B 3  is also formed out of a Galvalume steel sheet, and comprises flange portions  1 , cutouts  2 , a base plate portion  3 , a bulging portion  4 , nail openings  5 , screw holes  6 , ribs  7 , a left support portion  8 , a right support portion  9 , a central support portion  10 , a lower support portion  11 , a central horizontal raised portion  12   a,  upwardly bent portions  14 , front plate portions  15 , bearing portions  16  and upper-board locking portions  17 . A waterproof material D 1  is provided on the left and right ends of the central horizontal raised portion  12   a,  the top surfaces of the upwardly bent portions  14  and the front surfaces of the front plate portions  15 . The downwardly bent portion  13   b  is identical to the downwardly bent portion  13   a,  except that the former has a black tape adhered thereto. 
     As is the case in the fastening member B 1  illustrated in  FIG. 1 , the fastening member B 3  as well can be fixed reliably to the building frame side of a building, the exterior wall boards can be fixed stably, there can be locked a shiplap portion of the upper edge of an exterior wall board disposed below the fastening member B 3 , there can be locked shiplap portions of the lower edges of exterior wall boards that are disposed above the fastening member B 3 , the fastening member B 3  does not deform readily even under the action of external forces, and thus the exterior wall boards can be reliably fixed over long periods of time. The fastening member B 3 , moreover, can be manufactured easily and with good productivity, with manufacturing costs kept low. Rainwater or the like trickling down the vertical joint can be caught and reliably arrested by the central horizontal raised portion  12   a,  to be drained towards the front of the exterior wall by way of the downwardly bent portion  13   b.  The rainwater or the like can thus be arrested and drained over long periods of time. 
     Moreover, the downwardly bent portion  13   b  of the fastening member B 3  has a black tape adhered thereto. Being black, therefore, the downwardly bent portion  13   b  of the fastening member B 3  remains unnoticed even when gaps form at the seams between exterior wall boards due to contraction of the exterior wall boards themselves or due to distortion of the entire structure to which the exterior wall boards are mounted. The downwardly bent portion  13   b  is protected by the tape adhered thereto, and is thus less susceptible to corrosion and deterioration. 
       FIG. 8  is a diagram illustrating yet another example of an external wall construction structure according to the present invention, in which the fastening member illustrated in  FIG. 7  is fixed to the building frame of a building. 
     The fastening member B 3  illustrated in  FIG. 7  is identical to the fastening member B 1  illustrated in  FIG. 1 , except that herein the downwardly bent portion  13   b  has a black tape adhered thereto. Therefore, the external wall construction structure illustrated in  FIG. 8  is identical to the external wall construction structure illustrated in  FIG. 2  except that herein the downwardly bent portion  13   b  has a black tape adhered thereto. In the external wall construction structure illustrated in  FIG. 8  as well, the fastening member B 3  can be reliably fixed to the backing material F thanks to screws E that are driven through the screw holes  6 , with the base plate portion  3  and the flange portions  1  abutting the backing material F. Likewise, the exterior wall boards A can be fixed stably thanks to the screws E that are driven through the screw holes  6 , with the left support portion  8 , the right support portion  9 , the central support portion  10  and the lower support portion  11  of the fastening member B 3  abutting the back surface of the exterior wall board A. The exterior wall board A that is positioned below the fastening member B 3  can be reliably fixed thanks to the screws E that are driven through the screw holes  6 , with the central horizontal raised portion  12   a  and the downwardly bent portion  13   b  of the fastening member B 3  locking the shiplap portion of the upper edge of the exterior wall board A that is positioned below the fastening member B 3 . The exterior wall boards A that are positioned above the fastening member B 3  can be reliably fixed thanks to the screws E that are driven through the screw holes  6 , with the bearing portions  16  and the upper-board locking portions  17  of the fastening member B 3  locking the shiplap portions of the lower edges of the exterior wall boards A that are positioned above the fastening member B 3 . The exterior wall boards A are fixed by way of the fastening member B 3  having the cutouts  2  in the vicinity of the inward sides of the left support portion  8  and the right support portion  9 . A highly stable fastened state can be maintained as a result for long periods of time. In the fastening member B 3 , the waterproof material D 1  comprising bentonite and provided on the left and right ends of the central horizontal raised portion  12   a,  the top surfaces of the upwardly bent portions  14  and the front plate portions  15  is fixed abutting the shiplap portions of the lower edges of the exterior wall boards A that are disposed above the fastening member B 3 . Therefore, even if small gaps exist between the shiplap portions of the lower edges of the exterior wall boards A and the fastening member B 3 , the gaps are thus filled up by the bentonite of the waterproof material D 1 , which swells on account of the first rainwater that intrudes. Rainwater or the like trickling down the vertical joint can be caught and reliably arrested by the central horizontal raised portion  12   a,  to be drained towards the front of the exterior wall by way of the downwardly bent portion  13   b.  The rainwater or the like can thus be arrested and drained over long periods of time. 
     Moreover, the downwardly bent portion  13   b  of the fastening member B 3  has a black tape adhered thereto. Being black, therefore, the downwardly bent portion  13   b  of the fastening member B 3  remains unnoticed even when gaps form at the seams between exterior wall boards due to contraction of the exterior wall boards themselves or due to distortion of the entire structure to which the exterior wall boards are mounted. The downwardly bent portion  13   b  is protected by the tape adhered thereto, and is thus less susceptible to corrosion and deterioration. 
     Although not shown in  FIG. 8 , another exterior wall board A is locked at the upper right position of the fastening member B 3 . Specifically, this other exterior wall board A is fixed by the fastening member B 3  in such a manner that the back surface of the exterior wall board A abuts the right support portion  9  and the central support portion  10  of the fastening member B 3 , while the shiplap portion of the lower edge of the exterior wall board A is locked on the bearing portion  16  and the upper-board locking portion  17 . 
       FIG. 9  is a diagram illustrating an external wall comprising multiples rows of the external wall construction structures illustrated in  FIG. 8 . 
     In  FIG. 9 , the exterior wall is formed of a plurality of exterior wall boards A that are fastened in a staggered layout to the building frame of a building by means of the fastening member B 3  illustrated in  FIG. 7  and the fastening stopper C illustrated in  FIG. 18 . The exterior wall illustrated in  FIG. 9  is identical to the exterior wall illustrated in  FIG. 3 , except that the fastening member B 1  of the exterior wall illustrated in  FIG. 3  is now the fastening member B 3 . 
     Therefore, the exterior wall boards A can be fixed stably over long periods of time. The fastening member B 3  is fixed at the sites where the shiplap portions of three exterior wall boards A meet to form an inverted T-joint. Even if small gaps exist between the shiplap portions of the lower edges of the exterior wall boards A and the fastening member B 3 , the gaps are thus filled up by the bentonite of the waterproof material D 1 , which swells on account of the first rainwater that intrudes. Rainwater or the like trickling down the vertical joint can be caught and reliably arrested by the central horizontal raised portion  12   a,  to be drained towards the front of the exterior wall by way of the downwardly bent portion  13   b.  The rainwater or the like can thus be arrested and drained over long periods of time. 
     Moreover, the downwardly bent portion  13   b  of the fastening member B 3  has a black tape adhered thereto. Being black, therefore, the downwardly bent portion  13   b  of the fastening member B 3  remains unnoticed also in cases were gaps form at sites where the shiplap portions of three exterior wall boards A meet to form an inverted T-joint, due to contraction of the exterior wall boards A themselves or due to distortion of the entire structure to which the exterior wall boards A are mounted. The downwardly bent portion  13   b  is protected by the tape adhered thereto, and is thus less susceptible to corrosion and deterioration. 
     Embodiment 4 
       FIG. 10  is a diagram illustrating yet another embodiment of a fastening member according to the present embodiment. 
     A fastening member B 4  illustrated in  FIG. 10  is identical to the fastening member B 1  illustrated in  FIG. 1 , except that herein a central horizontal raised portion  12   b  has a black tape adhered thereto, and a downwardly bent portion  13   b  has a black tape adhered thereto. Specifically, the fastening member B 4  is also formed out of a Galvalume steel sheet, and comprises flange portions  1 , cutouts  2 , a base plate portion  3 , a bulging portion  4 , nail openings  5 , screw holes  6 , ribs  7 , a left support portion  8 , a right support portion  9 , a central support portion  10 , a lower support portion  11 , upwardly bent portions  14 , front plate portions  15 , bearing portions  16  and upper-board locking portions  17 . A waterproof material D 1  is provided on the left and right ends of the central horizontal raised portion  12   b,  the top surfaces of the upwardly bent portions  14  and the front surfaces of the front plate portions  15 . The central horizontal raised portion  12   b  is identical to the central horizontal raised portion  12   a,  except that the former has a black tape formed thereon. The downwardly bent portion  13   b  is identical to the downwardly bent portion  13   a,  except that the former has a black tape adhered thereto. 
     As is the case in the fastening member B 1  illustrated in  FIG. 1 , the fastening member B 4  as well can be fixed reliably to the building frame side of a building, the exterior wall boards can be fixed stably, there can be locked a shiplap portion of the upper edge of an exterior wall board disposed below the fastening member B 4 , there can be locked shiplap portions of the lower edges of exterior wall boards that are disposed above the fastening member B 4 , the fastening member B 4  does not deform readily even under the action of external forces, and thus the exterior wall boards can be reliably fixed over long periods of time. The fastening member B 4 , moreover, can be manufactured easily and with good productivity, with manufacturing costs kept low. Rainwater or the like trickling down the vertical joint can be caught and reliably arrested by the central horizontal raised portion  12   b,  to be drained towards the front of the exterior wall by way of the downwardly bent portion  13   b.  The rainwater or the like can thus be arrested and drained over long periods of time. 
     The central horizontal raised portion  12   b  and the downwardly bent portion  13   b  of the fastening member B 4  have each a black tape adhered thereto. Being black, therefore, the central horizontal raised portion  12   b  and the downwardly bent portion  13   b  of the fastening member B 4  remain unnoticed even when gaps form at the seams between exterior wall boards due to contraction of the exterior wall boards themselves or due to distortion of the entire structure to which the exterior wall boards are mounted. The central horizontal raised portion  12   b  and the downwardly bent portion  13   b  are protected by the tape adhered thereto, and are thus less susceptible to corrosion and deterioration. 
       FIG. 11  is a diagram illustrating yet another example of an external wall construction structure according to the present invention, in which the fastening member illustrated in  FIG. 10  is fixed to the building frame of a building. 
     The fastening member B 4  illustrated in  FIG. 10  is identical to the fastening member B 1  illustrated in  FIG. 1 , except that a black tape is adhered to the central horizontal raised portion  12   b  and the downwardly bent portion  13   b.  Therefore, the external wall construction structure illustrated in  FIG. 11  is identical to the external wall construction structure illustrated in  FIG. 2  except that herein a black tape is adhered to the central horizontal raised portion  12   b  and the downwardly bent portion  13   b.  Specifically, in the external wall construction structure illustrated in  FIG. 11  as well, the fastening member B 4  can be reliably fixed to the backing material F thanks to screws E that are driven through the screw holes  6 , with the base plate portion  3  and the flange portions  1  abutting the backing material F. Likewise, the exterior wall boards A can be fixed stably thanks to the screws E that are driven through the screw holes  6 , with the left support portion  8 , the right support portion  9 , the central support portion  10  and the lower support portion  11  of the fastening member B 4  abutting the back surface of the exterior wall board A. The exterior wall board A that is positioned below the fastening member B 4  can be reliably fixed thanks to the screws E that are driven through the screw holes  6 , with the central horizontal raised portion  12   b  and the downwardly bent portion  13   b  of the fastening member B 4  locking the shiplap portion of the upper edge of the exterior wall board A that is positioned below the fastening member B 4 . The exterior wall boards A that are positioned above the fastening member B 4  can be reliably fixed thanks to the screws E that are driven through the screw holes  6 , with the bearing portions  16  and the upper-board locking portions  17  of the fastening member B 4  locking the shiplap portions of the lower edges of the exterior wall boards A that are positioned above the fastening member B 4 . The exterior wall boards A are fixed by way of the fastening member B 4  having the cutouts  2  in the vicinity of the inward sides of the left support portion  8  and the right support portion  9 . A highly stable fastened state can be maintained as a result for long periods of time. In the fastening member B 3 , the waterproof material D 1  comprising bentonite and provided on the left and right ends of the central horizontal raised portion  12   b,  the top surfaces of the upwardly bent portions  14  and the front plate portions  15  is fixed abutting the shiplap portions of the lower edges of the exterior wall boards A that are disposed above the fastening member B 4 . Therefore, even if small gaps exist between the shiplap portions of the lower edges of the exterior wall boards A and the fastening member B 4 , the gaps are thus filled up by the bentonite of the waterproof material D 1 , which swells on account of the first rainwater that intrudes. Rainwater or the like trickling down the vertical joint can therefore be caught and reliably arrested by the central horizontal raised portion  12   b,  to be drained towards the front of the exterior wall by way of the downwardly bent portion  13   b.  The rainwater or the like can thus be arrested and drained over long periods of time. 
     The central horizontal raised portion  12   b  and the downwardly bent portion  13   b  of the fastening member B 4  have each a black tape adhered thereto. Being black, therefore, the central horizontal raised portion  12   b  and the downwardly bent portion  13   b  of the fastening member B 4  remain unnoticed even when gaps form at the seams between exterior wall boards due to contraction of the exterior wall boards themselves or due to distortion of the entire structure to which the exterior wall boards are mounted. The central horizontal raised portion  12   b  and the downwardly bent portion  13   b  are protected by the tape adhered thereto, and are thus less susceptible to corrosion and deterioration. 
     Although not shown in  FIG. 11 , another exterior wall board A is locked at the upper right position of the fastening member B 4 . Specifically, this other exterior wall board A is fixed by the fastening member B 4  in such a manner that the back surface of the exterior wall board A abuts the right support portion  9  and the central support portion  10  of the fastening member B 4 , while the shiplap portion of the lower edge of the exterior wall board A is locked on the bearing portion  16  and the upper-board locking portion  17 . 
       FIG. 12  is a diagram illustrating an external wall comprising multiples rows of the external wall construction structures illustrated in  FIG. 11 . 
     In  FIG. 12 , the exterior wall is formed of a plurality of exterior wall boards A that are fastened in a staggered layout to the building frame of a building by means of the fastening member B 4  illustrated in  FIG. 10  and the fastening stopper C illustrated in  FIG. 18 . The exterior wall illustrated in  FIG. 12  is identical to the exterior wall illustrated in  FIG. 3 , except that the fastening member B 1  of the exterior wall illustrated in  FIG. 3  is now the fastening member B 4 . 
     Therefore, the exterior wall boards A can be fixed stably over long periods of time. The fastening member B 4  is fixed at the sites where the shiplap portions of three exterior wall boards A meet to form an inverted T-joint. Even if small gaps exist between the shiplap portions of the lower edges of the exterior wall boards A and the fastening member B 4 , the gaps are thus filled up by the bentonite of the waterproof material D 1 , which swells on account of the first rainwater that intrudes. Rainwater or the like trickling down the vertical joint can therefore be caught and reliably arrested by the central horizontal raised portion  12   b,  to be drained towards the front of the exterior wall byway of the downwardly bent portion  13   b.  The rainwater or the like can thus be arrested and drained over long periods of time. 
     The central horizontal raised portion  12   b  and the downwardly bent portion  13   b  of the fastening member B 4  have each a black tape adhered thereto. Being black, therefore, the central horizontal raised portion  12   b  and the downwardly bent portion  13   b  of the fastening member B 4  remain unnoticed also in cases were gaps form at sites where the shiplap portions of three exterior wall boards A meet to form an inverted T-joint, due to contraction of the exterior wall boards themselves or due to distortion of the entire structure to which the exterior wall boards are mounted. The central horizontal raised portion  12   b  and the downwardly bent portion  13   b  are protected by the tape adhered thereto, and are thus less susceptible to corrosion and deterioration. 
     Embodiment 5 
       FIG. 13  is a diagram illustrating yet another embodiment of a fastening member according to the present embodiment. 
     A fastening member B 5  illustrated in  FIG. 13  is identical to the fastening member B 1  illustrated in  FIG. 1 , except that herein a central horizontal raised portion  12   c  is coated with a black epoxy resin coating, a downwardly bent portion  13   c  is coated with a black epoxy resin coating, and a waterproof material D 2  comprises bentonite and EPDM. Specifically, the fastening member B 5  is also formed out of a Galvalume steel sheet, and comprises flange portions  1 , cutouts  2 , a base plate portion  3 , a bulging portion  4 , nail openings  5 , screw holes  6 , ribs  7 , a left support portion  8 , a right support portion  9 , a central support portion  10 , a lower support portion  11 , upwardly bent portions  14 , front plate portions  15 , bearing portions  16  and upper-board locking portions  17 . The waterproof material D 2  is provided on the left and right ends of the central horizontal raised portion  12   c,  the top surfaces of the upwardly bent portions  14  and the front surfaces of the front plate portions  15 . The central horizontal raised portion  12   c  is identical to the central horizontal raised portion  12   a,  except that the former is coated with a black epoxy resin coating. The downwardly bent portion  13   c  is identical to the downwardly bent portion  13   a,  except that the former is coated with a black epoxy resin coating. 
     As is the case in the fastening member B 1  illustrated in  FIG. 1 , the fastening member B 5  as well can be fixed reliably to the building frame side of a building, the exterior wall boards can be fixed stably, there can be locked a shiplap portion of the upper edge of an exterior wall board disposed below the fastening member B 5 , there can be locked shiplap portions of the lower edges of exterior wall boards that are disposed above the fastening member B 5 , the fastening member B 5  does not deform readily even under the action of external forces, and thus the exterior wall boards can be reliably fixed over long periods of time. The fastening member B 5 , moreover, can be manufactured easily and with good productivity, with manufacturing costs kept low. Rainwater or the like trickling down the vertical joint can be caught and reliably arrested by the central horizontal raised portion  12   c,  to be drained towards the front of the exterior wall by way of the downwardly bent portion  13   c.  The rainwater or the like can thus be arrested and drained over long periods of time. 
     The central horizontal raised portion  12   c  and the downwardly bent portion  13   c  of the fastening member B 5  are coated with a black epoxy resin coating. Being black, therefore, the central horizontal raised portion  12   c  and the downwardly bent portion  13   c  of the fastening member B 5  remain unnoticed even when gaps form at the seams between exterior wall boards due to contraction of the exterior wall boards themselves or due to distortion of the entire structure to which the exterior wall boards are mounted. The central horizontal raised portion  12   c  and the downwardly bent portion  13   c  are protected by the black epoxy resin coating, and are thus less susceptible to corrosion and deterioration. 
       FIG. 14  is a diagram illustrating yet another example of an external wall construction structure according to the present invention, in which the fastening member illustrated in  FIG. 13  is fixed to the building frame of a building. 
     The fastening member B 5  illustrated in  FIG. 13  is identical to the fastening member B 1  illustrated in  FIG. 1 , except that herein the central horizontal raised portion  12   c  and the downwardly bent portion  13   c  are both coated with a black epoxy resin coating. Therefore, the external wall construction structure illustrated in  FIG. 14  is identical to the external wall construction structure illustrated in  FIG. 2  except that herein the central horizontal raised portion  12   c  and the downwardly bent portion  13   c  are both coated with a black epoxy resin coating. In the external wall construction structure illustrated in  FIG. 14  as well, the fastening member B 5  can be reliably fixed to the backing material F thanks to screws E that are driven through the screw holes  6 , with the base plate portion  3  and the flange portions  1  abutting the backing material F. Likewise, the exterior wall boards A can be fixed stably thanks to the screws E that are driven through the screw holes  6 , with the left support portion  8 , the right support portion  9 , the central support portion  10  and the lower support portion  11  of the fastening member B 5  abutting the back surface of the exterior wall board A. The exterior wall board A that is positioned below the fastening member B 5  can be reliably fixed thanks to the screws E that are driven through the screw holes  6 , with the central horizontal raised portion  12   c  and the downwardly bent portion  13   c  of the fastening member B 5  locking the shiplap portion of the upper edge of the exterior wall board A that is positioned below the fastening member B 5 . The exterior wall boards A that are positioned above the fastening member B 5  can be reliably fixed thanks to the screws E that are driven through the screw holes  6 , with the bearing portions  16  and the upper-board locking portions  17  of the fastening member B 5  locking the shiplap portions of the lower edges of the exterior wall boards A that are positioned above the fastening member B 5 . The exterior wall boards A are fixed by way of the fastening member B 5  having the cutouts  2  in the vicinity of the inward sides of the left support portion  8  and the right support portion  9 . A highly stable fastened state can be maintained as a result for long periods of time. The waterproof material D 2 , provided at the left and right ends of the central horizontal raised portion  12   c,  the top surfaces of the upwardly bent portions  14  and the front plate portions  15  of the fastening member B 5 , and comprising bentonite and EPDM, is fixed abutting the shiplap portions of the lower edges of the exterior wall boards A that are disposed above the fastening member B 5 . Hence, even if small gaps exist between the shiplap portions of the lower edges of the exterior wall boards A and the fastening member B 5 , the gaps are thus filled up by the bentonite of the waterproof material D 2 , which swells on account of the first rainwater that intrudes. Rainwater or the like trickling down the vertical joint can be caught and reliably arrested by the central horizontal raised portion  12   c,  to be drained towards the front of the exterior wall by way of the downwardly bent portion  13   c.  The rainwater or the like can thus be arrested and drained over long periods of time. 
     The central horizontal raised portion  12   c  and the downwardly bent portion  13   c  of the fastening member B 5  are both coated with a black epoxy resin coating. Being black, therefore, the central horizontal raised portion  12   c  and the downwardly bent portion  13   c  of the fastening member B 5  remain unnoticed even when gaps form at the seams between exterior wall boards due to contraction of the exterior wall boards themselves or due to distortion of the entire structure to which the exterior wall boards are mounted. The central horizontal raised portion  12   c  and the downwardly bent portion  13   c  are protected by the black epoxy resin coating, and are thus less susceptible to corrosion and deterioration. 
     Although not shown in  FIG. 14 , another exterior wall board A is locked at the upper right position of the fastening member B 5 . Specifically, this other exterior wall board A is fixed by the fastening member B 5  in such a manner that the back surface of the exterior wall board A abuts the right support portion  9  and the central support portion  10  of the fastening member B 5 , while the shiplap portion of the lower edge of the exterior wall board A is locked on the bearing portion  16  and the upper-board locking portion  17 . 
       FIG. 15  is a diagram illustrating an external wall comprising multiples rows of the external wall construction structures illustrated in  FIG. 14 . 
     In  FIG. 15 , the exterior wall is formed of a plurality of exterior wall boards A that are fastened in a staggered layout to the building frame of a building by means of the fastening member B 5  illustrated in  FIG. 13  and the fastening stopper C illustrated in  FIG. 18 . The exterior wall illustrated in  FIG. 15  is identical to the exterior wall illustrated in  FIG. 3 , except that the fastening member B 1  of the exterior wall illustrated in  FIG. 3  is now the fastening member B 5 . 
     Therefore, the exterior wall boards A can be fixed stably over long periods of time. The fastening member B 5  is fixed at the sites where the shiplap portions of three exterior wall boards A meet to form an inverted T-joint. Even if small gaps exist between the shiplap portions of the lower edges of the exterior wall boards A and the fastening member B 5 , the gaps are thus filled up by the bentonite of the waterproof material D 2 , which swells on account of the first rainwater that intrudes. Rainwater or the like trickling down the vertical joint can be caught and reliably arrested by the central horizontal raised portion  12   c,  to be drained towards the front of the exterior wall by way of the downwardly bent portion  13   c.  The rainwater or the like can thus be arrested and drained over long periods of time. 
     The central horizontal raised portion  12   c  and the downwardly bent portion  13   c  of the fastening member B 5  are both coated with a black epoxy resin coating. Being black, therefore, the central horizontal raised portion  12   c  and the downwardly bent portion  13   c  of the fastening member B 5  remain unnoticed also in cases were gaps form at sites where the shiplap portions of three exterior wall boards A meet to form an inverted T-joint, due to contraction of the exterior wall boards A themselves or due to distortion of the entire structure to which the exterior wall boards A are mounted. The central horizontal raised portion  12   c  and the downwardly bent portion  13   c  are protected by the black epoxy resin coating, and are thus less susceptible to corrosion and deterioration. 
     Embodiments of the present invention have been explained above, but the invention is not limited to or by the embodiments. Various modifications can be made to the embodiments without departing from the scope of the invention as set forth in the appended claims. For instance, the waterproof material D 2 , the central horizontal raised portion  12   b  and the downwardly bent portion  13   b  may be combined, and the exterior wall can be made up of two or more types of the fastening members B 1  to B 5 . The fastening members B 1  to B 5  may be used at sites other than the sites where the shiplap portions of three exterior wall boards meet to form an inverted T-junction, for instance at sites where the shiplap portion of the lower end and the shiplap portion of the upper end of two exterior wall boards fit each other. Instead of using screws, the fastening members B 1  to B 5  may be fixed by hammering nails through the nail openings  5 . A waterproof material formed of a laminate of bentonite and an elastic material may also be used instead of the waterproof material D 1  or the waterproof material D 2 . Further, not just the central horizontal raised portion and/or the downwardly bent portion but the entire fastening member may be coated in a blackish color. 
     The present invention allows providing a fastening member and an external wall construction structure in which the shiplap portions of the lower edges of the exterior wall boards that are put up above the fastening member abut the fastening member reliably, in which the abutting state of the fastening member with the shiplap portions of the lower edges of the exterior wall boards is preserved also after construction, and in which no part of the fastening member is noticeable, even when exposed through gaps at the seams between exterior wall boards.