Hip Roof Framing Calculator - With Rafter Angle Cutting Templates and Setout Plans - Metric
Rafter Join Detail
For a good straight fascia, add an extra 20 mm or so to the tails of all your rafters (total length).
After they're up, you can snap a line to mark and trim the tails in a nice straight line, to make up for any ridge warp or marking, cutting and fixing errors.
Mark, cut (and test fit) 1 common and 1 hip, then use as patterns to mark and cut the rest.
Left click, release then drag to measure at scale in diagram below
- Enlarge diagram scale for more accurate measurements.
To mark and cut hip plumb and side cuts with a circular saw
- Print a Paper Template
(easy + accurate) - OR:
Mark the end plumb cut angle line
back from square) on both sides of the hip. This is the pointy end of the hip. (Don't cut yet)
from this line and mark a second, parallel line on both sides of the hip. (This is the line to cut along)
Set circular saw blade tilt angle to 45°
, cut 1 side along second line, with blade tilted toward pointy end, then flip and cut other side the same.
Print and cut full scale paper templates - fold over wood to mark and cut angles (easy)
Porch Roof Extensions
For hip roof porch extensions from an existing building wall, you can use half the calculator results.
Enter the extension wall length into 'Wall Length' and double
the extension wall width, then minus
into the 'Wall Width' entries. (minus ridge thickness to allow for ridge becoming pole plate - roof peak will be slightly higher - Ridge Thick must be same as Common).
The resulting roof diagram is then 'cut in half' along the ridge top
line, with bottom half being the roof extension,
with the ridge and 2 end (King) common rafters becoming Pole Plates that attach to the existing building wall. ①
The roof extension length must be at least twice as long as its width, or the 2 hips will meet before they reach the existing building wall.
If the extension length is half the extension length, the 2 hips will meet at
the existing wall, and the roof will come to a peak
(with no ridge), like half a pyramid. ②
If the extension length is less than
twice the width, the 2 hips will meet before they reach the existing wall, and you'll need a ridge extending from the
existing wall at 90° to join the hips where they meet. In this case, you can enter the extension wall length into the 'Wall Width'
the extension wall width into 'Wall Length', then 'cut the diagram in half' length-ways at the centre.
(move or add 2 commons to become poll plates at existing wall) ③
For Porch Width 3000, enter 5950 Wall Width
Built something using our calculators?
Please Send Photos!