The document discusses hip roofs and hip rafters. It provides information on calculating the length of common rafters, hip rafters, and jack rafters for a hip roof with a given span, run, and roof slope. It also discusses shortening the ridgeboard and common rafters to accommodate their thickness, as well as methods for cutting the side cuts of hip and jack rafters.

1. HIP RAFTER
RIDGEBOARD
BACKING, BEVELLING,
DROPPING
THE HIP ROOF - 1

2. CARPENTRY, 2ND Canadian Ed., Vogt F. & Nauth M., Nelson Education, 2013
N.B. RUN is horizontal travel of the rafter or the base of the right triangle.
CR unit run = 12”
HR unit run = 16.97” (17”)

3. CARPENTRY, 2ND Canadian Ed., Vogt F. & Nauth M., Nelson Education, 2013

4. CARPENTRY, 2ND Canadian Ed., Vogt F. & Nauth M., Nelson Education, 2013

5. CARPENTRY, 2ND Canadian Ed., Vogt F. & Nauth M., Nelson Education, 2013
N.B. The common rafter (CR) is shortened by ½ the
thickness of the ridgeboard and the Ridgeboard is
lengthened, on each end, by ½ the thickness of the CR

6. CARPENTRY, 2ND Canadian Ed., Vogt F. & Nauth M., Nelson Education, 2013

7. CARPENTRY, 2ND Canadian Ed., Vogt F. & Nauth M., Nelson Education, 2013

8. CARPENTRY, 2ND Canadian Ed., Vogt F. & Nauth M., Nelson Education, 2013

9. CARPENTRY, 2ND Canadian Ed., Vogt F. & Nauth M., Nelson Education, 2013

10. CARPENTRY, 2ND Canadian Ed., Vogt F. & Nauth M., Nelson Education, 2013

11. CARPENTRY, 2ND Canadian Ed., Vogt F. & Nauth M., Nelson Education, 2013

12. CARPENTRY, 2ND Canadian Ed., Vogt F. & Nauth M., Nelson Education, 2013

13. CARPENTRY, 2ND Canadian Ed., Vogt F. & Nauth M., Nelson Education, 2013
Given: Building 18’ x 28’. Roof slope 4 in 12, roof projection 16”
Calculations: Span = 18’; Run = 9’
Using the Framing Square Tables:-
Line 1: Unit Common R. = 12.65”, LLCR = 12.65 x 9 = 113.85” = 9’ 5⅞”
Line 2: Unit Hip R. = 17.44”, LLHR = 17.44” x 9 = 156.96” = 13’ 15/16”
Line 3: Common Difference (16”o.c.) = 16⅞”, LLHJR#1 = (9’ 5⅞” – 1’ 4⅞”)
LLHJR#1 = 8’ 1”
Line 4: Common Diff. (24”o.c.) = 255/16”, LLHJR#1 = (9’ 5⅞” – 2’ 15
/16”)
LLHJR#1 = 7’ 39
/16”
Line 5: Side Cut of Jacks = 12” & 11⅜”
Line 6: Side Cut of Hip or Valley = 12” & 1111/16”
In the next slide, line 6 is replaced by simply shortening the 1st ridge plumb line
by 11/16” (½ the 45 thickness of the hip rafter or the diagonal of a ¾” square),
and then by a further ¾” for ½ the thickness of the hip rafter stock. The line is
cut with the bevel of the circsaw set at 45 .

14. CARPENTRY, 2ND Canadian Ed., Vogt F. & Nauth M., Nelson Education, 2013
The slot in the speed
square has numbers
above for the unit rise
for the hip rafter and it
has numbers below for
the unit rise for the
common rafter. Once
the angle is set to be
marked off, the degrees
are read at the bottom
edge.