How To Cut Common Rafters---Pt. 1
This article is written to help take the pain out of trying to cut common rafters for any type of building. In the example below, we will be cutting 2x8 rafters for a common 6/12 pitch gabled roof building 30' wide.
Terminology
Span---------------The measurement of the total width of a building--- (rough frame only).
Run----------------The measurement of half the width of a building--(rough frame only).
Plumb Cut----------Any vertical cut to a rafter.
Seat Cut-----------Any any horizontal cut to a rafter.
Bird's Mouth-------Combination of plumb cut and seat cut created on rafter at area that connects rafter to wall.
Ridge Board--------Framing member Where the rafters meet at the center of the roof.
Fascia-------------The vertical area of rafter at overhang.
Soffit-------------The horizontal area of overhang created by rafters.
Step By Step Instructions:
Calculating Your Rafters
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Measure the total width of your building-- (this measurement is known as the --" SPAN" of the building).
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Divide the "SPAN" in half-- (this measurement is known as the--
"RUN" of the building. -
Laying Out Rafters With 2' Framing Square.
It is recommended that someone
who is cutting rafters to be familiar with the terminology of the 2' Framing Square. This Square is used in multiple areas of construction and most for building an entire home.
So, needless to say, you need a 2' Framing Square to layout your rafters.
If you cannot follow along with the terminology in the next couple of paragraphs please find a framing square along with the very short manual and read up.
Another small tool that comes in handy when you layout rafters are a pair of stair guides that you can purchase at your nearest hardware store. You don't need them but they make the handling of the 2' Framing Square a little easier.
The framing square has 2 blades on it, one long blade (body-24") and one short blade (tounge-16").
The Tongue numeric graduations are for the rise or pitch of the roof. and
the Body numeric graduations are for the run of the roof (12") or if your dealing with a hip roof then it would be set at (17")--also this part of the square is for the seat cuts also known as level cuts.
continue--->HOW TO CUT COMMON RAFTERS Pt.2
