Roof Geometry ns
description
Transcript of Roof Geometry ns
ROOF GEOMETRY
GABLE ROOFSIMILAR TRIANGLES
PYTHAGOREAN THEOREM
ISOSCELES TRIANGLE2 sides equal
The Perpendicular Bisector divides the base into 2 parts.
Two Equal Triangles Equal Angles
THIS IS THE LINE DRAWING OF THE SIDE VIEW OF THE GABLE ROOF
AB = AC = Rafter line; BD = DC = Total Run; BC = Total Span; AD = Total Rise
𝐴2+𝐵2=𝐶2
C =
Video on Pythagoras' Theorem
http://learni.st/learnings/99012-pythagoras-theorem?board_id=13622
This is a D.A.L. calculator
• Direct Algebraic Logic
• You enter numbers and
symbols as you would write
themPYTHAGORAS’ THEOREM
Given: A = 4’, B = 3’
Find: C
Calc.: C =
On the Calculator:
Press: ( 4 x2 + 3 x2 ) =
Screen: (42 + 32) = 5
Roof Slope is denoted by the # of inches of rise over 12” of run.
i.e. vertical rise over the unit horizontal run of 12”
Slope(imp.) = = = , for example
Written as 6 in 12, 6:12, 6/12, or
In metric, as per the Building Code, 1 in 2 or 1:2
12
6
12
6
Pythagorean Theorem
6
12
Hypotenuse
Hypotenuse =
=
=
= 13.42”
This is called the unit length of the Common Rafter.