1. Roof Connection Details

2. Eave & Rake Details
Definition: Architectural details that incorporates the roof to the wall assembly
Common members included in details:
fascia and fascia trim
soffit and soffit vents
lookout or outrigger
slope/pitch
rafter and ceiling joist
double top plate

3. Terms to Know--Rake Detail
Definition: Detail taken at the sloped edge of roof or at the gable end of the building, usually this detail is perpendicular to Eave Details

4. Terms to Know--Fascia Finished member secured to end of rafters
Some construction include a sub-fascia in preparation to receiving a finished fascia.

5. Terms to Know--Soffit
Enclosed/boxed-in area or open area below rafters on the overhang of a roof
Soffit Area

6. Terms to Know--Eave Detail
The projecting portion of the roof parallel to the slope. Sometimes called the cornice detail
To draw eave detail, architect needs to know
roof material--wood vs. composition shingles
rafter size & spacing
roof/eave overhang
roof slope/pitch
roof sheathing
exterior wall sheathing
eave design
Eave Detail

7. Roof Pitch Pitch Rise over Span
Always reduced to the smallest fraction

8. Roof Slope
Slope
Slope is stated as a ratio of rise over run with run, run is 1/2 of span but is always expressed as a base of 12
Slope is placed on a detail as a upside down triangle with 12 (run) horizontal line and rise by the vertical line

9. Drafting Slope in a Detail
Assume the slope is 6:12 as shown below
All is necessary is to determine hypotenuse of a triangle having a base of 12 units and the leg of 6 units
Draft a line 12” long using the scale of your drawing
Then a vertical line 6” long with the same scale
The diagonal is the slope for this problem
SLOPE LINE for DETAILING
6” LEG LINE
12” BASE LINE

10. Calculations for Slope
Problem: Span of a building is 30’, Rise is 5’, what is the slope?
Run = 1/2 Span = x 30 = 15
Slope = Rise/Run = 5/15 = x/12 (Convert) x = 5x12
x(new rise) = (5x12)/15
x(new rise) = 4
SLOPE = 4:12

11. 2) Enclosed (Boxed) or Open Soffit 3) Fascia Styles and Designs
Eave Designs
1) Exposed tail rafters
2) Enclosed (Boxed) or Open Soffit
3) Fascia Styles and Designs

12. 1) Exposed Tail Rafters
An exposed wood member that is spliced to the common rafters
Usually thicker than common rafter with the spacing further apart

13. Boxed Cornice--Soffit Styles
1) Boxed Horizontal
2) Boxed Parallel to rafter, sloped
3) Either styles can be Open or Enclosed

14. 2) Boxed (Enclosed) verses Open Soffit
Boxed Horizontal or Boxed Parallel to rafter and sloped
Open Soffit
Boxed Horizontal Soffit
Slopped Open Soffit

15. Soffit Design Considerations
1) Must make provision for ventilation
eave soffit (intake) and attic (exhaust)
2) Determine area of ventilation
Attic area (x) 1/150 = total area of ventilation req’d (net free area)
3) Determine location of ventilation
eaves-- soffit contiuous vs. soffit cutout
gable ends--square, rectangle, round or triangle shape
ridge --continuous along roof ridge
roof --various types projecting out of the roof

16. Ventilation Products/Suppliers
Ventilation Types:
1) Roof Louvers
2) Gable Louvers
3) Ridgeline Vents
4) Gravity Turbines
5) Power Vents

17. 3) Fascia Styles and Designs
vertical vs perpendicular
Fascia vertical to rafter
Fascia perpendicular to rafter

18. Drafting the Eave Detail
It is recommended to complete the eave detail design before drafting other roof details
Common eave/cornice detail scale sizes:
1 1/2" = 1'-0"
3/4" = 1'-0"
1" = 1'-0"

19. Rake Detail Rake - assembly along sloping edge of roof
Usually different overhang from eave
No need to “notch” for rafters

20. Detail Example Eave Detail Notes Scale: 1 1/2” = 1’-0”
5-Ply built-up roof w/ 50# building edge
3/4” CDX plywood
5/8” GB (Interior finish)
38R fiberglass batt insulation(12”)(ceiling)
2x8 CLG
Pre-fab trusses optional
1x6 T&G siding over 1/2” OSB 15# felt between
(Match previous details)
Add 1x3 trim at fascia
Full fiberglass batt insulation in wall

21. Detail Notes Continued Scale: 1 1/2” = 1’-0”
Attic insulation R38- 12” foil faced fiberglass batt
2x8 rafter and ceiling 24” OC (or prefab wd truss)
1/2” AC exterior plywood soffit
7/8” stucco exterior finish w/ 1x2 redwood ground at top next to soffit
24” overhang (from stucco to fascia)
2x4 24” OC
R11-3 1/2” craft faced fiberglass batt in (2x4 16” OC