There was a major revision of the Building Standard Law in May 1999,promulgated and enacted in June 2000 to decide the structure of the building and the method of construction.Along with that,in the roof tile industory we announced the roof construction method "roof tile standard design,enforcement guidlines"based on scientific data. Tis allows you to withstand earthquakes ranging from average wind speed 30m to 40m and seismic intensity 7. Also,because the current tile itself is a disaster prevention specification,it is possible to do stronger construction with disaster prevention tile and guidline construction method. The establishments that are members of the union activiely introduce this construction method.Roof construction contractors not joining the union may not recognize the construction method itself. If you make roof light,itis not secure with respect to seismic force and wind pressure.What is important is to increase the load bearing wall,or to increace the seismic resistance against horizontal forces(sismic force and wind pressure)by changing low wall magnifications and walls that are not load bearing wall to high wall magnification,ect.Measures are required. Roofing materials are exposed to the most severe weather conditions.It is important to choose with performance regardless of weight.To the roof of Japan with hot and humidity and cold weather difference,selecting excellent roofing material(clay roof tile)that does not require durability,sound insulation,and maintenance as much as possible can say the secret of home building success. Moreover,it is also important to make earthquake resistance dliagosis/reinforcement because deterioration such as the foundation of the old building and foundation can be considered. 1.A bearing wall is required according to the building standard act. Depending on the floor area of the buildingand the size of the Mitsuke area of the outer wall,the building can withstand the horizontal force(seismic force)generated during an earthquake or the horizontal force(wind pressure)generated during a typhoon. 　　　　　　　　　　　　　　　　 *Mitsuke wall is the area ecpect the part of 1.35m or less from the floor of each floor. The Great amendment of the Building Standards Law was made in 1986.There is a big difference in earthquake resistance as to wether it is before 1968 or later.Therefore,in older buildings that are not tolerant,it is not safe to merely reduce the weight of the roof just by changing the "heavy roof"to "a kight roof"in some case.When choosing roofing materials with remodeling ect.,it is important to receive seismic diagnosis and secure the necessary wall amount for safty. We will explain "What is the difference between the calculation of wall volume and the difference in wall volume ?" The earthquqke resistance standard of Building Standard Law was changed in 1981.  (Required load bearing wall amount became 1.4 times,and proof strength against earthquake was enhanced.) Prior earthquake-resistant standard housing was dominated by clay roof tiles and cement roofing materials. (Clay roof tiles have a history as roofing material and were used as it was for old houses at the time.) Hopuses collapsed by an earthquake are mostly old houses before earthquake resistance standards change. (It has been reported by many construction research institutes such as national institutions and universities. The image of the collapsed house was reported as if it is caused by heavy clay roof tiles and cement roofing material. (As a means of conveying the damage,roof tiles were oicked up.) a）Amount of wall necessary for seismic force The wall coefficient due to seismic force is determined by the number of floors and the weight of the building.Only the length obtained byu multiplying the floor area of each floor by the wall coefficient requires walls in the X and Y directions of the building. Heavy roofing material (Ceramic tile / Cement roofing material)  Caluculation of required wall volume Floor space（㎡）×Coeffient（cm/㎡）×０.０１＝Required wall volume（ｍ） Light roofing material (Slate / metal roofin material) Earthquake coefficient（cm/㎡）  Earthquake coefficient（cm/㎡）  1 floor 2 floor 3 floor 1 floor 2 floor 3 floor Light roofing material(both X and Y axes) Heavy roofing material(both X and Y axes) 1st floor 　　　　　①41.41㎡(Floor space)×④33cm/㎡(Coefficient)×0.01＝13.67ｍ 　　　　　①41.41㎡(Floor space)×⑥29cm/㎡(Coefficient)×0.01＝12.01ｍ 2nd floor 　　　　　②28.99㎡(Floor space)×③21cm/㎡(Coefficient)（係数）×0.01＝6.09ｍ 　　　　　②28.99㎡(Floor space)×⑤15cm/㎡(Coefficient)×0.01＝4.35ｍ b）Necessary wall volume for wind pressure *Wall area targeted for yellow area ※The required wind pressure varies depending on the direction. Example : General area("Heavy roof,light roof"is the same) *The coeffients are determined by region. General area:50cm/㎡　High wind area:50-75cm/㎡ 1st floor X axis diredtion Mitsuke area of 1st floor east face,west face 　　　⑦25.16㎡(wind pressure wall volume)×50cm/㎡(coefficient)×0.01＝12.58ｍ Y axis diredtion Mitsuke area of 1st floor south face,north face 　　　⑧49.98㎡(wind pressure wall volume)×50cm/㎡(coefficient)×0.01＝9.71ｍ 2nd floor X axis diredtion Mitsuke area of 2nd floor east face,west face 　　　⑨10.54㎡(wind pressure wall volume)×50cm/㎡(coefficient)×0.01＝5.27ｍ Y axis diredtion Mitsuke area of 2nd floor south face,north face 　　　⑩19.41㎡(wind pressure wall volume)×50cm/㎡(coefficient)×0.01＝9.71ｍ c）Determination of the required wall volume The required wall volume of seismic force wind pressure is compared for each hierarchy and direction,and a large value is the required wall volume.   Unit : m Seismic force against Wind pressure force against Unit : m Seismic force against Wind pressure force against 1st floor X axis diredtion １３.６７ １２.５８ ← The difference is 1.09 m → 1st floor X axis diredtion １２.０１ １２.５８ Y axis diredtion １３.６７ ２２.９９ ← There is no difference → Y axis diredtion １２.０１ ２２.９９ 2nd floor X axis diredtion ６.０９ ５..２７ ← The difference is 0.82 m →  2nd floor X axis diredtion ４.３５ ５.２７ Y axis diredtion ６.０９ ９.７１  ← There is no difference → Y axis diredtion ４.３５ ９.７１ * In order to determine the wall volume to withstand seismic force and wind pressure,the wall volume will be the same regardless of the roofing materila if the wall volume of wind pressure at all locations like Y axis. * Like light roofing materials,the wall volume of wind pressure may all be exceeded. Difference of wall magnification(strength)by kind of wall volume Specification Bearing wall of brace 面材耐力壁 30 × 90 45×90 構造用合板 One side bracing Both sides bracing One side bracing Both sides bracing  One side Both sides Magnification 1.5 3.0 2.0 4.0 2.5 5.0 Shape Unit : m 3.0 Heavy roofing material Light roofing material The diffrernce is slightly for one bearing wall. Just make the partition a bearing wall. 1st floor X axis direction Required bearing wall length 13.67m 12.58m 1.5 number of wakks 13.67m÷1.5times÷0.91=10.01sheet 12.58m÷1.5times÷0.91=9.216sheet Required number of wall   Y axis direction Required bearing wall length 22.99m 22.99m 1.5 number of wakks 22.99m÷1.5times÷0.91=16.84sheet 22.99m÷1.5times÷0.91=16.84sheet Required number of wall 👈There is no difference