Hip & Valley
Hip Valley Roof
• This is to be used in conjunction with the
following plan which can be found here
Is the Roof a True Hip & Valley Roof
Spans are
equal
Is the Roof a True Hip & Valley Roof
Rise will be
the same and
ridges will
meet in the
centre
Is the Roof a True Hip & Valley Roof
If Spans are
not equal
ridges will not
meet
Is the Roof a True Hip & Valley Roof
If Spans are
not equal
ridges will not
meet
This part of
the roof is
still going
up
Is the Roof a True Hip & Valley Roof
If Spans are
not equal
ridges will not
meet
This part of the roof is
going down
This part of
the roof is
still going
up
Is the Roof a True Hip & Valley Roof
To Solve this
we have to
construct a
Broken Hip
which is the
next roof
Determine The Spans
Determine The Spans
Every Ridge must have a Span
Determine The Spans
Span is tied to the Basis
of the Common Rafter
Calculation
Determine The Spans
Same Rafters
Span is tied to the Basis
of the Common Rafter
Calculation
Determine The Spans
Same Rafters
Must be
same Span
Span is tied to the Basis
of the Common Rafter
Calculation
Hip & Valley Roof
• STEP 1
- As always
Determine the 1 metre triangles
-
Please review Gable & Hip roofs if you do not know how to do this
Rise per
1m of Rafter Plan length
1.000
1.414
Hip & Valley Roof
Pitch 32°
• STEP 1
- As always
Determine the 1 metre triangles
-
Please review Gable & Hip roofs if you do not know how to do this
0.625
1.000
√2
Hip & Valley Roof
• STEP 1
- As always
Determine the 1 metre triangles
Rafter = Plan Length x Rafter per m
-
Please review Gable & Hip roofs if you do not know how to do this
0.625
32°
1.000
1.414
Determine Common Rafter
Rafter = Plan Length x Rafter per m
= (5400 – 9.5) x 1.179
= 6356
Rafter 90 x 35 @ 450 c to c
Ridge 140 x 19
Valley 140 x 45
5400
0.625
32°
1.000
1.414
Determine Valley Rafter
Valley is determined in the exact
same manner as the Hip Rafter
Valley Rafter = ½ Span x Hip / m
= 2700 x 1.649
= 4452
The hip is usually measured as per
the Hip Rafter.
Calculation is only for estimating
5400
0.625
32°
1.000
1.414
Rafter 90 x 35 @ 450 c to c
Ridge 140 x 19
Valley 140 x 45
Determine Valley Rafter
for Estimating
Valley is determined in the exact same
manner as the Hip Rafter
Valley Rafter = (½ Span + O/H )x Hip / m
= (2700 + 600) x 1.649
= 5542 + 140 (Plumb Cut)
= 5682
= 5700
Note if Hip is required to be joined you
should allow at least 300mm
5400
0.625
32°
1.000
1.414
Rafter 90 x 35 @ 450 c to c
Ridge 140 x 19
Valley 140 x 45
Overhang 600
Plumb Cut Valley
209
Using Steel Square
÷3
471
5400
0.625
32°
1.000
1.414
Rafter 90 x 35 @ 450 c to c
Ridge 140 x 19
Valley 140 x 45
Overhang 600
Plumb Cut Valley
Pitch Mathematically
Tan Pitch° = Rise ÷ Plan Length
= 0.625 ÷ √2
= 0.442
Inv Tan (0.442) = 23.8° or 23.8°
(Note Inv is not mathematical inverse
Function but the Calculators Trig inverse
5400
0.625
32°
1.000
1.414
Rafter 90 x 35 @ 450 c to c
Ridge 140 x 19
Valley 140 x 45
Overhang 600
Valley True Length
½ Span = 2700
Valley Plan Length
= ½ Span – ½ Ridge Thickness
= 2700 – 17.5
= 2682.5
½ Span – ½ Ridge Thickness
Ridge 140 x 35
Valley True Length
½ Span = 2700
Valley Plan Length
= ½ Span – ½ Ridge Thickness
= 2700 – 17.5
= 2682.5
True Length
= Plan Length x Hip/m
= 2682.5 x 1.649
= 4423
½ Span – ½ Ridge Thickness
Ridge 140 x 35
Valley Creepers
Plan Length = ½ Span – (½ Valley x √2 + ½ Rafter) – ½ Ridge
= 2700 – (22.5 x √2 + 17.5) -17.5
½ Span = 2700
= 2618
Valley 140 x 45
Rafter 90 x 35
Ridge 140 x 35
Valley Creepers –
st
1
Creeper
Plan Length = ½ Span – (½ Valley x √2 + ½ Rafter) – ½ Ridge
= 2700 – (22.5 x √2 + 17.5) -17.5
= 2618
½ Span = 2700
True Length = Plan Length x Rafter /m
= 2618 x 1.179
= 3087
Valley 140 x 45
Rafter 90 x 35
Ridge 140 x 35
Valley Creepers –
st
1
Creeper
Plan Length = ½ Span – (½ Valley x √2 + ½ Rafter) – ½ Ridge
= 2700 – (22.5 x √2 + 17.5) -17.5
= 2618
½ Span = 2700
True Length = Plan Length x Rafter /m
= 2618 x 1.179
= 3087
Valley 140 x 45
Creeper Shortening
= Spacing x Rafter Length / m
= 450 x 1.179
Rafter 90 x 35
= 531
@ 450 c to c
This will be the same as the Hip
Ridge 140 x 35
Valley Creepers –
st
1
Creeper
Plan Length = ½ Span – (½ Valley x √2 + ½ Rafter) – ½ Ridge
= 2700 – (22.5 x √2 + 17.5) -17.5
= 2618
½ Span = 2700
True Length = Plan Length x Rafter /m
= 2618 x 1.179
= 3087
Valley 140 x 45
Creeper Shortening
= Spacing x Rafter Length / m
= 531
Rafter 90 x 35
@ 450 c to c
Ridge 140 x 35
Valley Creepers – All Creepers
Plan Length = ½ Span – (½ Valley x √2 + ½ Rafter) – ½ Ridge
= 2700 – (22.5 x √2 + 17.5) -17.5
= 2618
Valley Creeper
True Length = Plan Length x Rafter /m
No.
= 2618 x 1.179
1
= 3087
Creeper Shortening
= Spacing x Rafter Length / m
= 531
2
3
4
5
6
True
Length
3087
2556
2025
1494
963
432
Valley Creepers Plumb Cut
As it is the same pitch as the Rafter it is the same
Steel Square
313
500
Valley Creeper – Edge Bevel
Rafter Centreline Length
Same as Hip Creeper
½ Span
Ridge