chapter 5 light wood frame construction light wood framing advantages flexible flexible easily...
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Chapter 5Light Wood Frame Construction
Light Wood FramingLight Wood Framing
AdvantagesAdvantages FlexibleFlexible Easily constructedEasily constructed EconomicalEconomical
DisadvantagesDisadvantages Burns rapidly, Burns rapidly, Decays if exposed to moistureDecays if exposed to moisture Changes volume with moisture changes Changes volume with moisture changes Framing unattractive (must be covered) Framing unattractive (must be covered)
History - Prior to mid-1800sHistory - Prior to mid-1800s Timber Frame Timber Frame
timber with masonrytimber with masonry timber with earth fill timber with earth fill
Interior walls were simple plank structureInterior walls were simple plank structure
Trees were plentiful, and labor was Trees were plentiful, and labor was
intense.intense.
Craftsmen were available, but tools were Craftsmen were available, but tools were
limited – and had to be operated by hand.limited – and had to be operated by hand.
History - mid 1800sHistory - mid 1800s
Light wood framing advanced by Light wood framing advanced by Development of water powered saw millsDevelopment of water powered saw mills Machine made nails became availableMachine made nails became available
Earliest Version of Lt. Wood FramingEarliest Version of Lt. Wood Framing Balloon FramingBalloon Framing
Long lengths of material was plentifulLong lengths of material was plentiful
Wood members were small & easily Wood members were small & easily handledhandled
Provided for lateral stabilityProvided for lateral stability
Balloon FramingBalloon Framing Erection of wall framing members Erection of wall framing members
on a wood sill secured to the on a wood sill secured to the foundation foundation and lapped against the and lapped against the floor joists.floor joists.
Second floor Second floor joists lapped into the joists lapped into the wall framing system.wall framing system.
Roof framing then set on top of Roof framing then set on top of wall plates. Roof rafters tied to wall plates. Roof rafters tied to ceiling joists secured lateral ceiling joists secured lateral displacement of exterior walls.displacement of exterior walls.
Components were light in Components were light in comparison to timber structures, comparison to timber structures, and erection required minimal and erection required minimal labor than before. labor than before. The practice The practice was a more efficient use of was a more efficient use of material.material.
DISADVANTAGES OF BALOON FRAMINGDISADVANTAGES OF BALOON FRAMING
Long, straight lengths of material diminished Long, straight lengths of material diminished in availability as more structures were built. in availability as more structures were built.
When buildings caught fire, When buildings caught fire, the wall cavity of the wall cavity of balloon framing allowed fire & smoke to balloon framing allowed fire & smoke to chimney all the way to the roofchimney all the way to the roof, and , and structures burned rapidly.structures burned rapidly.
Since the wall and floor structure were built Since the wall and floor structure were built integrally, integrally, most of the framing work was most of the framing work was done off the grounddone off the ground, where level conditions , where level conditions might not exist.might not exist.
• PLATFORM FRAMINGPLATFORM FRAMING
• With the disadvantages of With the disadvantages of balloon framing, the platform balloon framing, the platform frame system evolved.frame system evolved.
• The floor structure was first built The floor structure was first built onto the foundation sill, then onto the foundation sill, then decked to provide a ‘platform’ on decked to provide a ‘platform’ on which to work.which to work.
• Ground-floor walls were erected Ground-floor walls were erected with a top plate to receive the with a top plate to receive the second floor joists, which became second floor joists, which became a sill on which to erect the upper a sill on which to erect the upper floor joists – which, when decked floor joists – which, when decked became another platform.became another platform.
• Single floor framing was more Single floor framing was more plentiful because of shorter plentiful because of shorter lengths.lengths.
wallwallstuds
sill
PLATFORM
foundation
BALOON
floor
sub floor
joistssill
foundation
studs
joists
sub floor
floor
lapped second
BALOON
studswall
floor joists
ledgertemporary
joists arestuds and
second
2 - 2"x4"
floor joists
PLATFORM
studswall
plate
single 2"x4"plate
rafters
wallstuds
fascia2 - 2"x4"plate
deckroof
ceiling joists
Building SequenceBuilding Sequence Architect Plans and Designs the Facility – Architect Plans and Designs the Facility –
Then Prepares Design and Construction Then Prepares Design and Construction DocumentsDocuments
Involve a selected Contractor, who:Involve a selected Contractor, who: Obtains Building PermitObtains Building Permit Purchases necessary materialsPurchases necessary materials Selects Sub-Contractors for each phase of workSelects Sub-Contractors for each phase of work Excavation for utilities, foundationsExcavation for utilities, foundations Install Underground utility lines (electrical, Install Underground utility lines (electrical,
plumbing)plumbing) Foundation constructionFoundation construction Floor ConstructionFloor Construction Erect Framing for StructureErect Framing for Structure
Build construction pad & set batter Build construction pad & set batter boardsboards
Batter boards enable accurate layout of Batter boards enable accurate layout of foundationfoundation
A transit ensures accurate angles in A transit ensures accurate angles in layoutlayout
A level is used to ensure proper grades & A level is used to ensure proper grades & elevationelevation
Excavate & Place FoundationsExcavate & Place Foundations
Materials Typically Used:Materials Typically Used: Site Cast ConcreteSite Cast Concrete Concrete Masonry UnitsConcrete Masonry Units Reinforcing SteelReinforcing Steel Tie wireTie wire Anchor BoltsAnchor Bolts
Foundation and Basement Wall Foundation and Basement Wall ConstructionConstruction Construction for support of loadsConstruction for support of loads Damp proofing and/or perimeter Damp proofing and/or perimeter
insulationinsulation
Foundation Wall SystemsFoundation Wall Systems
Concrete or CMU Wall
Gravel for
Drainage
Perforated Drainage
Pipe
Drainage Stone under floor slab
with Vapor Barrier
Damp-proofing
Concrete grade beam
Sill
Anchor
Utility installation is simultaneous with foundation Utility installation is simultaneous with foundation workwork
Installation of Plumbing Drainage PipingInstallation of Plumbing Drainage Piping
Underground Plumbing
Example of grade beam monolithic with concrete Example of grade beam monolithic with concrete floorfloor
Thickened Slab on grade
Granular Base
WallLoad
Installation of plastic vapor barrier under concrete Installation of plastic vapor barrier under concrete floorfloor
Granular SubBase
Vapor Barrier
Foundation Foundation InsulationInsulation Some building codes Some building codes
require perimeter require perimeter insulation at foundations – insulation at foundations – especially in cold climates.especially in cold climates.
Insulate the Crawl Space Insulate the Crawl Space or Basement Wallsor Basement Walls Attach to Platform or on Attach to Platform or on
GroundGround Vapor BarrierVapor Barrier
Building the Platform Frame in Wood Floor Building the Platform Frame in Wood Floor With Crawl SpaceWith Crawl Space
Sequence of AssemblySequence of Assembly Install sills with insect barriersInstall sills with insect barriers Bolt sill members to the FoundationBolt sill members to the Foundation Install floor framing and bridgingInstall floor framing and bridging Install floor deckingInstall floor decking
Attachment to the Attachment to the FoundationFoundation
Sill MaterialSill Material Treated for Treated for
resistance to resistance to insects & decay in insects & decay in damp climates.damp climates.
Install insect shields Install insect shields
Sill Attachment with Sill Attachment with anchor boltsanchor bolts
Floor Framing OptionsFloor Framing Options
FRAME WITH DIMENSION LUMBER
FRAME FLOORSUSING TRUSSES
FRAME FLOORS WITH “I” JOISTS
Floor Framing Floor Framing Spacing & SplicingSpacing & Splicing
SpacingSpacing Factors that determine joist spacing:Factors that determine joist spacing:
Floor Loading & Span Length Floor Loading & Span Length Strength of Joist Material UsedStrength of Joist Material Used Type & thickness of floor deckingType & thickness of floor decking
Designation - Inches “o.c.” (on center)Designation - Inches “o.c.” (on center) Typical - 12” , 16”, or 24” – to fit standard Typical - 12” , 16”, or 24” – to fit standard
lumber lengths)lumber lengths)
Bridging for Floor Framing Bridging for Floor Framing
Floor Framing Floor Framing Using Steel AnchorsUsing Steel Anchors
Decking over Floor Decking over Floor Framing Framing
Materials UsedMaterials Used Plywood or OSBPlywood or OSB Concrete or gypsum is poured over Concrete or gypsum is poured over
second floor decks for sound deadeningsecond floor decks for sound deadening
InstallationInstallation Deck is laid perpendicular to floor joistsDeck is laid perpendicular to floor joists End joints are staggered to brace joistsEnd joints are staggered to brace joists Power nails, screws, construction Power nails, screws, construction
adhesiveadhesive
Building Sequence for Ground Floor Building Sequence for Ground Floor WallsWalls
LayoutLayout Sole plates installed to define wall Sole plates installed to define wall locationslocations
Wall Framing - Lay out studs & Wall Framing - Lay out studs & assemble with single top wall plateassemble with single top wall plate
Tilt up walls on the Platform & fasten Tilt up walls on the Platform & fasten to sole plateto sole plate
Install second layer of top wall plate Install second layer of top wall plate to tie all partitions and walls together.to tie all partitions and walls together.
Install Wall SheathingInstall Wall Sheathing Corner bracing required for lateral Corner bracing required for lateral stability – usually OSB or plywood at stability – usually OSB or plywood at all exterior cornersall exterior corners
Sole Plate
Top Plate - DoubledStud
Sheathing
Header
Framing Terminology
Decking
HeadersHeaders Headers are beams installed over Headers are beams installed over
openings to carry weight of second openings to carry weight of second floor or roof loads.floor or roof loads.
Sizing Factors: Sizing Factors: Load, Span, Material Load, Span, Material Materials: dimension lumber, Materials: dimension lumber,
Laminated wood, orLaminated wood, or SteelSteel
Erecting the Wall FramingErecting the Wall Framing
Build framing on the Platform & Tilt-up, Build framing on the Platform & Tilt-up, brace, and fasten to sole plates. brace, and fasten to sole plates.
Double Top PlateDouble Top Plate Joist SupportJoist Support Tie Framing Tie Framing
TogetherTogether
Double HeaderHeader Supports
Double Top Plate
Corner Framing
Sole Plate Anchorage
Wall SheathingWall Sheathing
Materials:Materials: OSB or Plywood for corner bracingOSB or Plywood for corner bracing Insulating Sheathing - Insulating Sheathing - (no structural qualities)(no structural qualities)
Exterior Wall SheathingExterior Wall Sheathing:: Joins & stabilizes the structureJoins & stabilizes the structure Resists upliftResists uplift Resists racking & lateral forcesResists racking & lateral forces Provides surface for finish materialProvides surface for finish material
Building Sequence Building Sequence PLATFORM & 2PLATFORM & 2NDND Story Walls Story Walls
Erect 2nd Story Platform Erect 2nd Story Platform Similar to 1st Floor SequenceSimilar to 1st Floor Sequence Install 2nd Floor access (stairs)Install 2nd Floor access (stairs)
Erect 2nd Story Walls & Erect 2nd Story Walls & SheathingSheathing Similar to 1st Floor SequenceSimilar to 1st Floor Sequence
Building Sequence Building Sequence Attic Floor & RoofAttic Floor & Roof
OptionsOptions Build-in-place ceiling joists, Build-in-place ceiling joists,
rafters, and bracing, ORrafters, and bracing, OR
Prefabricated Trusses, ORPrefabricated Trusses, OR
CombinationCombination
RaftersRidge Board
Roof Framing Built-in-PlaceRoof Framing Built-in-Place
Collar Ties
LOOKOUTS TO FORM
OVERHANGS
GABLE FRAMING
Prefabricated Roof TrussesPrefabricated Roof Trusses
Note Strand Orientation
Hurricane Clip
Metal clips in decking prevent uneven deflectionMetal clips in decking prevent uneven deflection
Roof ProfilesRoof Profiles
Flat RoofFlat Roof
Single PitchSingle Pitch
Roof ProfilesRoof Profiles
Gable RoofGable Roof
Hip RoofHip Roof
Hip
Ridge
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