Roof framing cdujb

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Roof framing cdujb

  1. 1. ROOF FRAMING<br />MEMBERS AND CALCULATIONS.<br />
  2. 2. ROOF FRAMING<br />RAFTERS<br />HIPS<br />VALLEYS<br />CREEPERS<br />UNDER PURLINS<br />PURLIN PROPS<br />OUT RIGGERS<br />CRIPPLE CREEPERS<br />COLLAR TIES<br />
  3. 3. RAFTERS<br />
  4. 4. RAFTERS<br />
  5. 5. THE RAFTERS ARE THE MAIN STRUCTURE OF THE ROOF FRAME .<br />THE RAFTERS SPAN ACROSS THE COMPLETE DISTANCE OF THE EXTERNAL WALL FRAMES.<br />THE MAIN RAFTERS ARE CALLED <br />COMMON RAFTERS .<br />
  6. 6. HIPS<br />
  7. 7. THE HIPS ARE VERY SIMILAR AS RAFTERS EXCEPT THEY COME FROM THE CORNERS OF THE HOUSE EG: 45o<br />THE HIPS ARE CUT AT THE SAME PITCH AS THE RAFTERS BUT HAVE A DIFFERENT PLUMB CUT.<br />HIP RAFTERS-<br />
  8. 8. VALLEY RAFTER<br />
  9. 9. VALLEY SET OUTS.<br />
  10. 10. VALLEYS ARE THE SAME AS HIPS EXCEPT THEY START AND FINISH FROM THE INTERNAL CORNERS OF THE HOUSE FRAME ./ STILL AT 45o.<br />VALLEYS<br />
  11. 11. CREEPER RAFTERS.<br />
  12. 12. CREEPERS ARE ALSO KNOWN AS CREEPER RAFTERS .<br />THEY ARE THE RAFTERS THAT COME OFF THE HIP AT RIGHT ANGLES.<br />EACH CREEPER HAS A SHORTENING AT THE SAME DISTANCE.<br />CREEPERS<br />
  13. 13. UNDER PURLINS<br />
  14. 14. THE UNDER PURLIN IS FIXED UNDER THE RAFTERS AND 2/3rds UP THE ROOF SLOPE FROM THE TOP PLATES .<br />TO ASSIST IN THE CORRECT POSITIONING OF THE UNDER PURLIN LOCATION LINES SHOULD BE SET OUT ON THE PATTERN RAFTER. <br />UNDER PURLIN<br />
  15. 15. PURLIN PROPS<br />
  16. 16. PURLIN PROPS ARE THE UP RIGHT MEMBERS THAT SUPPORT THE ROOF LOAD.<br />THEY SIT ON TOP OF A WALL PLATE AND CONNECT TO THE UNDER PURLIN THIS IS CALLED A POINT LOAD AND SHOULD BE SUPPORTED TO THE GROUND.<br />PURLIN PROPS<br />
  17. 17. CRIPPLE CREEPERS<br />
  18. 18. CRIPPLE CEEPERS ARE SIMILAR TO CREEPERS ALTHOUGH THEY START FROM THE RIDGE OR FLYING HIP AND FINISH AT THE VALLEY.<br />THE DIFFERENCE BETWEEN THE CREEPER AND THE CRIPPLE CREEPER IS THAT THERE IS NO BIRDSMOUTH CUT . IT IS A STRAIGHT PLUMB CUT AT ONE END AND A REVERSED CREEPER CUT AT THE OTHER.<br />CRIPPLE CREEPERS<br />
  19. 19. COLLAR TIES<br />
  20. 20. COLLAR TIES ARE USED TO TIE THE OPPOSING RAFTERS TOGETHER. <br />TO STOP THEM FROM DROPPING AND FALLING APART.<br />COLLAR TIES ARE SET INTO POSITION<br />2/3rds UP THE ROOF SLOPE AND SIT ON <br />TOP OF THE UNDER PURLIN, THEN NAILED.<br /> COLLAR TIES<br />
  21. 21. RAFTER LENGTH CALCULATION EXAMPLE.<br />FIND THE SPAN EXAMPLE 6000 mm<br />FIND THE 1/2 SPAN EXAMPLE 3000 mm<br />FIND THE 1/2 SPAN MINUS 1/2 RIDGE THICKNESS<br />EXAMPLE 3000mm MINUS 19mm<br /> = 2981 mm<br />
  22. 22. RIDGE SIZE = 175 X 38<br />ROOF PITCH = 40 deg 2’<br />BUILDING SPAN = 6000 mm<br />BUILDING HALF SPAN = 3000 mm <br /> = 2981 mm<br /> = 3892 mm<br />ROOF FRAMING<br />
  23. 23. 1/2 SPAN MINUS 1/2 RIDGE THICKNESS<br />= 2981mm<br /> 2000 mm = 2612 mm<br /> 900 mm = 1175 mm<br /> 80 mm = 104mm<br /> 1 mm = 1 mm<br />TOTAL RAFTER LENGTH = 3892 mm<br />ROOF FRAMING<br />

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