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


Rise will be the same and ridges will meet in the centre


If Spans are not equal ridges will not meet



This part of the roof is still going up



This part of the roof is still going up

This part of the roof is going down


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

Determine The Spans


Same RaftersMust be same Span

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

1.000 1.414

Rise per1m of Rafter Plan length

Rafter Length per

1m of Rafter Plan lengthHip Length per

1m of Rafter Plan length

Hip & Valley Roof



1.000 √2

0.6251.179 1.546

Pitch 32°

Hip & Valley Roof



1.000 1.414

0.6251.179 1.649

32°

Rafter = Plan Length x Rafter per m

Determine Common Rafter

Rafter = Plan Length x Rafter per m = (5400 – 9.5) x 1.179 = 6356

5400

Rafter 90 x 35 @ 450 c to cRidge 140 x 19Valley 140 x 45

1.000 1.414

0.6251.179 1.649

32°

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

Rafter 90 x 35 @ 450 c to cRidge 140 x 19Valley 140 x 45

1.000 1.414

0.625

1.649

32°

1.179

Determine Valley Rafterfor 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

Rafter 90 x 35 @ 450 c to cRidge 140 x 19Valley 140 x 45Overhang 600

1.000 1.414

0.625

1.649

32°

1.179

Plumb Cut ValleyUsing Steel Square

5400


1.000 1.414

0.625

1.649

32°

1.179

471

209

÷3

Plumb Cut ValleyPitch Mathematically

5400


1.000 1.414

0.625

1.649

32°

1.179

Tan Pitch° = Rise ÷ Plan Length= 0.625 ÷ √2= 0.442

Inv Tan (0.442) = 23.8° or 23.8°(Note Inv is not mathematical inverseFunction but the Calculators Trig inverse

Valley True Length

Valley Plan Length = ½ Span – ½ Ridge Thickness= 2700 – 17.5= 2682.5

½ S

pan

– ½

Rid

ge T

hick

ness

½ Span = 2700

Ridge 140 x 35

Valley True Length

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 S

pan

– ½

Rid

ge T

hick

ness

½ Span = 2700

Ridge 140 x 35

Valley CreepersPlan Length = ½ Span – (½ Valley x √2 + ½ Rafter) – ½ Ridge = 2700 – (22.5 x √2 + 17.5) -17.5 = 2618 ½ Span = 2700

Ridge 140 x 35

Rafter 90 x 35

Valley 140 x 45

Valley Creepers – 1st CreeperPlan Length = ½ Span – (½ Valley x √2 + ½ Rafter) – ½ Ridge = 2700 – (22.5 x √2 + 17.5) -17.5 = 2618True Length = Plan Length x Rafter /m = 2618 x 1.179 = 3087

½ Span = 2700

Ridge 140 x 35

Rafter 90 x 35

Valley 140 x 45


Creeper Shortening = Spacing x Rafter Length / m

= 450 x 1.179 = 531This will be the same as the Hip

½ Span = 2700

Ridge 140 x 35

Rafter 90 x 35@ 450 c to c

Valley 140 x 45



= 531

½ Span = 2700

Ridge 140 x 35

Rafter 90 x 35@ 450 c to c

Valley 140 x 45

Valley Creepers – All CreepersPlan Length = ½ Span – (½ Valley x √2 + ½ Rafter) – ½ Ridge = 2700 – (22.5 x √2 + 17.5) -17.5 = 2618True Length = Plan Length x Rafter /m = 2618 x 1.179 = 3087


= 531

Valley Creeper No.

True Length

1 30872 25563 20254 14945 9636 432

Valley Creepers Plumb Cut

As it is the same pitch as the Rafter it is the same

500

313Steel Square

Valley Creeper – Edge Bevel

½ Span

Rafter Centreline Length

Same as Hip Creeper

Ridge

Hip & Valley

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