Hip & Valley Roofs

1. Hip & Valley Roofs Note: Main pictures and text (although some re-written) is from the text book “Practical Australian Carpentry” Created by M. S. Martin Oct. 2004 / Reviewed July 2007

2. Component Information • This sketch opposite is from carp. 12 text, or similar is on P370 BCGCA3007B and gives good overview of new members • Other sketches come from the Practical Australian Carpentry text and your handouts

3. Components continued • Also be able to recognize the difference between • Hip & Valley and • Broken Hip & Valley

4. Handout • Hip & Valley Roofs

5. Good overview of components

6. Easiest way to cut overhang

7. Hip & Valley Roofs • You already know hips bisect the angle of an external corner • A Valley is formed in a pitched roof wherever an internal angle / corner is found on the roof plan • The main roof is referred to as the “major roof” and has the major span • What's known as the offset is the “minor roof” and has the minor span • The offset is important, see next slide and handout for reference

8. Note the offset in red = No new bevels need to be developed The pitch of the roof remains the same = = Equal length of offset shown

9. New Roof Members • Copy these as notes on your hand out • Valley Rafter – The valley runs from the internal corner to the minor ridge and forms the junction of the sloping roof members. On plan it will bisect the internal corner and has a plumb & edge bevel which are the same as the plumb and edge bevel hip rafter Notes continue over next few slides

10. New Members Continued • Broken Hip Rafter – This rafter joins the main ridge to the minor ridge and is part of a full hip rafter that would form the corner of the main roof before the offset was added

11. New Members continued • Valley Creepers – These are rafters running from a ridge to the valley rafter and have the same bevels as the other creepers and provided the spacing remains constant, the same difference in length.

12. New Members continued • Cripple Rafter or Crippled Creeper – This runs from the broken hip to the valley rafter, isolating the offset and valley, it is a single line development of that portion of the roof. The dimensions shown in your notes, (handout) are in addition to the hipped roof and will be used in future examples. Fig 13.23 shows arrangements of roof members when thickness is added. • This is shown on next slide • Length of crippled creeper can be done mathematically or measured in-situ

13. Valley Creeper & Crippled Creeper

14. Set out of plates • As shown in your handout and on following slide, the wall plates for the minor roof are set out in a similar manner to the major roof. • While setting out the plates it is an ideal time to set out the minor ridge • A very strong job will result if the ridge is projected beyond the valley gathering point and fixed to the next rafter • Review in your notes and next slide

15. Note: the set out of the rafters are in the direction of the arrow shown opposite Wall plate set-out for valley

16. Calculations • Page 6 of your handout shows calc’s for creeper reductions, if you choose to do them this way • Example uses pitch of 30°, therefore the rise per / m run is 577mm and the true length per / m is 1.155m • ½ span of the minor roof is 1.350m, spacings of 600mm • Centre line length for minor roof is T/L per / m x ½ span 1.155 x 1.350 = 1.559 True length creeper reduction is T/L per / m x spacings 1.155 x .600 = .693 See next slide for example

17. Key: - major span - minor span - reductions Pattern Rafter set-out

18. Pitching the hip & Valley • Pitch the main hip roof as much as possible first • With a straight edge, check that the minor ridge will line up with the rafters on the main roof. • A temporary prop may be used for support • Locate the valley gathering point, partly drive a nail into it,s position • The centre line of the broken hip must gather at this point • Use a steel tape to measure broken hip • Use a straight edge or rule to accurately locate this point • Fix broken hip into position See notes and next slide for picture

19. Accuracy and positioning is the key to getting this right Measuring the broken hip

20. Use a straight edge to help when fixing broken hip

21. Length of valley rafter • Use a steel tape & measure as shown • The following pictures show a tail on the valley • It is not uncommon to cut tail off and let common rafters form internal corner for facia • Take note of next slide & your notes in reference to cutting valley

22. Valley Rafter set-out

23. Cutting valley creepers • With broken hip & valley now in position, valley creepers can now be fixed. • Provided spacing remains the same, the difference in the length of the valley creepers is the same as for the hip creepers • Notes and next slide show a practical way to determine the length of the first valley creeper • Mark the rafter spacing from the last common rafter to the long point of the creeper • Using steel tape measure from the ridge to this point

24. Valley Creeper set-out

25. Fixing valley creepers • After you cut the longest creeper shown on previous slide • Other creepers will then shorten in length by the creeper difference • See sketch opposite and in your handouts • Valley creepers are fixed above the edge of the valley rafter

26. Finishing the hip & valley frame • Proceed to fix any outstanding common or creeper rafters • Continue with purlins and strutting as previously learnt • Then the eaves overhang is marked and cut to length • Fix facia boards • Fix valley boards • The roof is now ready for the roof plumber