Hip & Valley RoofsNote: 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 / Reviewed June 2010

Component Information This sketch opposite

is from carp. 12 text, on P 73 gives good overview of new members

Other sketches come from the Practical Australian Carpentry text and your handouts

Components continued Also be able to

recognize the difference between

Hip & Valley and Broken Hip &

Valley P 72 textbook

Handout Hip & Valley Roofs

Good overview of components

Easiest way to cut overhang

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

Hip & Valley Roofs

=

=

Note the offset in red =

The pitch of the roof remains the same

No new bevels need to be developed

Equal length of offset shown

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

New Roof Members

Notes continue over next few slides

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

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.

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

New Members continued

Valley Creeper & Crippled Creeper

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

Set out of plates

Note: the set out of the rafters are in the direction of the arrow shown opposite

Wall plate set-out for valley

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

Calculations

See next slide for example

Key: - major span- minor span- reductions

Pattern Rafter set-out

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

Pitching the hip & Valley

See notes and next slide for picture

Accuracy and positioning is the key to getting this right

Measuring the broken hip

Use a straight edge to help when fixing broken hip

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

Valley Rafter set-out

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

Cutting valley creepers

Valley Creeper set-out

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

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

Finishing the hip & valley frame

Photo’s courtesy of Mick Taylor