Strong Built Establishments Builders SBE Builders is a commercial and residential framing contractor located in Discovery Bay California. Our Systematic Construction Logic produces Strong Built Establishments. E-Defense stands for Earthquake-Defense. Is your building ready for the next Earthquake?

Ellipse Formulas for Eyebrow Roof Design for Architects.

Intersecting Slope Angle = arctan((Roof Pitch - Dormer Pitch ) ÷ 12)
Semi Minor Axis = Radius
Roof Surface Semi Major Axis = ( Radius ÷ tan( Intersecting Slope Angle ) ) ÷ cos( Roof Pitch Angle )
Plan View Semi Major Axis = Radius ÷ tan( Intersecting Slope Angle )
Elevation View Semi Major Axis = ( Radius ÷ tan( Intersecting Slope Angle ) ) * tan( Roof Pitch Angle )

Ellipse Formulas Eyebrow Roof Drawings

Here's a link to some of the pictures I took in Billy Dillon's Eyebrow Dormer Class in Portland Oregon and pictures of the eyebrow dormer model I built a couple weeks after Billy's class.
Billy's Dillons Eyebrow Roof Dormer Class in Portland Oregon

The Eyebrow Roof Dormer Class in Portland Oregon was hosted by Lavrans Mathiesen Woodworking
Lavrans Mathiesen
Lavrans Mathiesen Woodworking
304 SE Main St. #4
Portland, Oregon 97214
(503) 351-4774

Eyebrow Roof Dormer Geometric Development
SBG = Story Board From Ground Line 0
SBG-1
SBG-2
SBG-3
SBG-4
SBG-5
SBG-6
V-1 Rafter Bevel
V-2 Roof Surface Valley Bevel
V-3 Inner Valley Bevel

SBE Builders 5305 Laguna Ct. Discovery Bay, California 94505 (925) 634-6022 • Fax: (925) 634-6022 Commercial & Residential Framing Contractor Build it Green Framing Contractor American Carpenter and Builder Licensed Building Contractor CA LIC.#  546126

Roof Framing Geometry

Roof framing geometry is empirical-type knowledge. Information gained by means of observation, experience, or experiment. From ground Line 0: Z1, Z2, Z3 etc... To Roof Axis 0: A1, A2, A3 etc... To the bring back line 0 for scribing: B1, B2, B3 etc...