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