Hip

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 calcs 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