Framing Agriculture Structures

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					Unit A3-9
 Framing
Agriculture
Structures
Problem Area 3
 Construction
  Systems
    Lesson 9
Framing Agriculture
    Structures
Interest Approach
ÜWhat type of framing is used on
 machine sheds and houses?
ÜWhy do these buildings fail (fall
 down)?
ÜWhat are some parts of a building?
Student Learning Objectives
Ü Discuss designing for building strength.
Ü Discuss and compare building shapes.
Ü Discuss and compare framing systems.
Ü Explain how to identify building
  framework components.
Ü Explain how to lay out rafters.
Terms
Ü Band joists                 Ü Fascia
Ü Bird’s mouth                Ü Floor joists
Ü Block plate or sill plate   Ü Full-arch type building
Ü Bridging                    Ü Gable-type building
Ü Clear-span buildings        Ü Gambrel-type roof
Ü Collar tie                  Ü Girts
Ü Concrete block building     Ü Header
Ü Curved half-arch            Ü Hip-type roof
  buildings                   Ü Jack studs
Ü Dead loads
Terms Continued
Ü Light wood-frame      Ü Rigid arch building
  (stud) construction   Ü Rise
Ü Live loads            Ü Roof pitch
Ü Lower cripples        Ü Rough sill
Ü Lower plate           Ü Run
Ü Lower plumb line      Ü Shed-type building
Ü Overhang length       Ü Sill sealer
Ü Pole buildings        Ü Slope triangle
Ü Purlins               Ü Soffit
Ü Rafter tail
Terms Continued
Ü Span
Ü Subfloor
Ü Trimmers
Ü Truss
Ü Upper chords
Ü Upper cripples
Ü Upper plate
Ü Upper plumb line
Ü Wall sheathing
  What can be done to prevent
       building failures?
ÜBuildings are built from the opposite
 order they are decided upon.
    1st type of roof is decided
    2nd type of side construction is
   decided
    Finally foundation or support is
   decided because it depends on weight
   and style of house
Potential Building Weak Points
ÜFoundation-wall    joint - Points where
 the walls and foundation meet.
ÜWall-roof joint - Points where the
 walls meet the roof.
ÜRoof ridge joint - Point where the
 roof peaks.
  Designing Buildings That Will
  Withstand Loads and Stresses
ÜDead   Load
  constant permanent load
  parts of the structure such as the
  weight of the roof inside
   Designing Buildings That Will
   Withstand Loads and Stresses
ÜLive   Load
  temporary loads that can be moved
  without altering the structure.
   –Wind Load (maximum PSI expected)
   –Snow Load (maximum PSI probably)
Building Shapes
ÜShed-type  building - roof sloping in
 one direction
ÜGable-type building - one roof angle
 on each side with the peak in the
 middle
ÜHip-type roof - similar to gable-type
 except the roof is brought down to
 the height of side walls
Building Shapes
ÜGambrel-type roof - two different
 slopes on each side.

ÜFull or Half arch roof - steel rounded
 building
Building Framing Systems
ÜLight wood - frame (stud)
 construction - concrete foundation
 with stud walls with 2x4 or 2x6
 studs.
ÜPole building - Round poles that are
 spaced 10 to 14 ft apart; usually
 inexpensive to build.
Building Framing Systems
ÜRigid arch building - metal or
 wooden framework with the roof
 framing and wall framing fastened
 together
ÜConcrete block building - concrete
 block walls with rafter or trusses to
 form the roof; usually more
 expensive to build
How Rafters are marked out
ÜBuilder   needs to know:
   Span (full width)
   Run (half width of building)
   Rise (total height increase from
  walls to peak of roof)
     How rafters are marked
ÜRoof   pitch- defined as the rise or
 span

ÜSlope    triangle- inches of rise or foot
 of run
         How rafters are marked
Ü Look   at the common rafter table on the
  framing square.
Ü Look under the inch mark that represents the
  rise or foot of run for the building in question.
Ü Multiply that number by the total run.
Ü Divide the answer by 12 to get the rafter
  length in feet.
Ü The rafter length is marked out on a marking
  line (1½ inches from the bottom of a 2 ×4 or
  2inches from the bottom of a 2 ×6).
        How rafters are marked
Ü The   upper plumb line is the marked
  angle at the top of the rafter.
Ü It is marked using the rise or foot of run
  and the number 12.
Ü Measure where the upper plumb line
  intersects with the marking line at the
  upper end of the board along the
  marking line to the length that was
  calculated.
         How rafters are marked
Ü That  location will be the point of the
  bird’s mouth.
Ü The bird’s mouth is the notch in the
  rafter where it sets on the wall.
Ü The angled cut at the lower end of the
  rafter is called the lower plumb line.
Ü The rafter tail is the rafter from the bird’s
  mouth to the lower plumb line.
     How rafters are marked
ÜWhen    the rafter is in place on the
 roof, the horizontal distance from
 the bird’s mouth notch to the lower
 plumb line is called the overhang
 length.
      How rafters are marked
ÜTo  calculate the rafter tail length that
 is marked on the board, take the
 number on the rafter table under the
 rise or foot of run and multiple it by
 the desired overhang length.
ÜAll rafter cuts are marked using the
 rise or foot of run and the number
 12.
        Rafter marking example
Ü Forexample, the rafter for a 5–12
 building would be marked using the
 numbers 6 and 12.
       Rafter marking example
Ü If the building total run was 10 feet and the
  overhang was 2 feet, then using the
  number 13.00 inches found under the 5 in
  the rafter table would result in a rafter
  length of 130 inches or 10 foot 10 inches
  (13 × 10) and a overhang length of 26
  inches or 2 foot 2 inches (13 inches × 2).
Ü If a ridge piece is used between a pair of
  rafters each rafter must be shortened by
  half of the width of the ridge piece.
Review/Summary
ÜWhat  are some potential weak
 points of buildings?
ÜWhat are some different building
 shapes?
ÜWhat are some different framing
 systems?
ÜHow do you lay out a rafter?

				
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posted:7/23/2013
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