Transcript Oblique End - Mirkos Trade 10 Wiki

Oblique End & Skew End Roof
Solve Angles x and y
Walls are parallel
Solve Angles x and y
Determine relevant
triangle
Walls are parallel
Solve Angles x and y
Tan y = Opp/ Adj
Tan y = 2000 / 900
Walls are parallel
Solve Angles x and y
Tan y = 2.222
Angle y = 65.8⁰
Walls are parallel
Solve Angles x and y
Angle Z =180 – 90 - 65.8⁰
Walls are parallel
Solve Angles x and y
Angle Z = 24.2⁰
Walls are parallel
Solve Angles x and y
Angle X = 24.2⁰ + 90⁰
Walls are parallel
Solve Angles x and y
Angle X = 114.2⁰
Walls are parallel
Oblique End Roof
Determine Position of Centring Rafters
Position Centring Rafter
If we extend ridge (which is central) it
will intersect with centre of splay end
Positioning Centring Rafter
Two Similar Triangles will be
formed, 1 half the size of the other
Positioning Centring Rafter
Remember for later
Therefore we can say the ridge
extension length is half the length
of the splay end extension
Position Centring Rafters
Remember Hips MUST
Bisect Corners
Position Centring Rafters
Remember Hips MUST
Bisect Corners
(Angles will vary)
Positioning Centring Rafter
90⁰
x
x
Corner is
Bisected this
must also = x
Positioning Centring Rafter
90⁰
Ѳ
x
x
To form Triangle
Ѳ = 180 – 90 – x
Ѳ = 90 - x
Positioning Centring Rafter
90⁰
90⁰ - x
x
x
Hip is at 90⁰ to
Centring Rafters
Positioning Centring Rafter
90⁰
x
90⁰ - x
Ѳ⁰
Ѳ = 90⁰ – 90⁰ - x
x
Positioning Centring Rafter
90⁰
x
90⁰ - x
Ѳ⁰
Ѳ=x
x
Positioning Centring Rafter
x
90⁰
To form triangle
Ѳ =180⁰ - x – x
= 180⁰ - 2x
x
90⁰ - x
x
Ѳ
Positioning Centring Rafter
x
90⁰
x
90⁰ - x
x
180⁰ - 2x
Ѳ
If the angles formed by a T
intersection must total 180⁰
Ѳ =180 ⁰ - (180⁰ - 2x)
= 2x
Positioning Centring Rafter
x
90⁰
x
90⁰ - x
x
180⁰ - 2x
2x
Centring Rafters are at 90⁰ to
Ridge & Wall Plates
Positioning Centring Rafter
x
90⁰
x
90⁰ - x
x
180⁰ - 2x
2x
The internal angles of a 4 Sided
polygon must total 360⁰
Positioning Centring Rafter
90⁰
x
x
90⁰ - x
x
180⁰ - 2x
2x
Ѳ
Ѳ = 360⁰ - 90⁰ - 90⁰ - 2x⁰
= 180⁰ -2x
Positioning Centring Rafter
90⁰
x
x
90⁰ - x
x
180⁰ - 2x
2x
Remember Hips bisect corners
180⁰ - 2x
Positioning Centring Rafter
x
90⁰
90⁰ - x
x
180⁰ - 2x
2x
Ѳ
180⁰ - 2x
Ѳ
Ѳ = 180⁰ - 2x
2
2
= 90⁰ - x
Positioning Centring Rafter
x
90⁰
x
90⁰ - x
x
180⁰ - 2x
2x
Ѳ = 180⁰ - 2x
2
2
90⁰ - x
= 90⁰ - x
90⁰ - x
Positioning Centring Rafter
x
90⁰
x
90⁰ - x
x
180⁰ - 2x
2x
Ѳ
90⁰ - x
90⁰ - x
Complete the Triangle
Ѳ = 180⁰ - 90⁰ - (90⁰ - x)
= x
Positioning Centring Rafter
x
90⁰
x
90⁰ - x
x
Ѳ
180⁰ - 2x
2x
x
90⁰ - x
90⁰ - x
Angle between Rafters & Ridge is 90⁰
Ѳ = 90⁰ - x
Positioning Centring Rafter
x
90⁰
x
90⁰ - x
x
180⁰ - 2x
90⁰ - x
2x
x
90⁰ - x
90⁰ - x
Angle between Hip Rafters
Ѳ = 90⁰ - x + x
= 90⁰
Positioning Centring Rafter
x
90⁰
x
90⁰ - x
x
180⁰ - 2x
90⁰ - x
Angle between Hip Rafters = 90⁰
2x
x
90⁰ - x
90⁰ - x
Positioning Centring Rafter
90⁰
90⁰ -x
x
x
Therefore we can say
1. When the corners of a splayed end roof
are bisected they will intersect at the ridge
2. The angles formed by the hips will be 90⁰
90⁰
x
90
90⁰ - x
Positioning Centring Rafter
If we centre a circle on the intersection of the
Ridge & skew end
=
Then make the diameter the length
Of the skew end
=
The circle will pass thru the corners
Positioning Centring Rafter
Lines from each end of a diameter that
intersect on the circumference of the
Circle will intersect at 90⁰
=
=
Positioning Centring Rafter
If we extend lines from these intersections
To the centre of the circle
=
=
Positioning Centring Rafter
If we extend lines from these intersections
To the centre of the circle
They must be radiuses
=
=
Positioning Centring Rafter
The ridge line extended past the centring
Rafter must be a radius of this circle
Positioning Centring Rafter
The Ridge Extension must equal the
half length of the Splay end
=
=
=
Positioning Centring Rafter
=
=
=
Positioning Centring Rafter
Previously we determined that the length of
The ridge extension was half the splay end
extension
=
=
=
Positioning Centring Rafter
Therefore the offset must equal
Radius – Half Splay Extension
=
=
=
Positioning Centring Rafter
Better we can say
Half Spay End Length – Half Splay Extension
1097 – 450 = 647
Positioning Centring Rafter
90⁰
x
x
Therefore we can say
If External walls are parallel
Hips always bisect corners
90⁰ -x
90⁰
x
90
1. When the corners of a splayed end roof
are bisected they will intersect at the ridge
2. The angles formed by the hips will be 90⁰
(This is the same for a conventional roof)
90⁰ - x
Solve Angle y
Developing from last week
90⁰
x
y
x
90
90⁰ - x
Solve Angle y
Developing from last week
1. Hips Always Bisect Corners
90⁰
x
x
y
x
90⁰ - x
90
90⁰ - x
Solve Angle y
Developing from last week
90⁰
x
1. Hips Always Bisect Corners
2. Rafters are always at 90° to wall plates
x
90⁰
y
x
90
90⁰ - x
Solve y
Developing from last week
90⁰
x
1. Hips Always Bisect Corners
2. Rafters are always at 90° to wall plates
x
90⁰
This angle must = 90 - x
90 -x
x
90
90⁰ - x
Solve Crown End Run
90⁰
x
x
90⁰
90- x
90
90⁰ - x
Solve Crown End Run
90⁰
90- x
x
x
90⁰
This angle must be 90 - x
90- x
90
90⁰ - x
Solve Crown End Run
90⁰
90- x
x
x
90⁰
The angles in both these triangles
are the same
90- x
90
90⁰ - x
Solve Crown End Run
90⁰
90- x
x
x
90⁰
Therefore these triangles
are similar triangles
90- x
90
90⁰ - x
Solve Crown End Run
90⁰
90- x
x
x
90⁰
The Hypotenuse of these triangles
are the same
90- x
90
90⁰ - x
Solve Crown End Run
90⁰
90- x
x
x
The triangles are equal triangles
So all sides will be equal
90⁰
90- x
90
90⁰ - x
Solve Crown End Run
90⁰
90- x
x
x
Crown End Run = Half Span
90⁰
90- x
90
90⁰ - x
Solve Crown End Run
90⁰
90- x
x
x
Crown End Run = Half Span
90⁰
Crown End Rafter position will
Equal same distance as Centring
Rafters from the short end
90- x
90
90⁰ - x
Gathering Point
Similar to a conventional hip roof
the gathering point is at the
centreline of the Ridge & Centring
rafters
Gathering Point
Similar to a conventional hip roof
the gathering point is at the
centreline of the Ridge & Centring
rafters
Gathering Point
Similar to conventional
hip roof all members
that form the oblique
end hip have the same
rise as the common
rafters