6. WOOD LIGHT FRAME CONSTRUCTION6. WOOD LIGHT FRAME CONSTRUCTION

LIGHT WOOD FRAMING

AdvantagesFlexibleEasily constructedEconomical

DisadvantagesBurns rapidly, Decays if exposed to moistureChanges volume with moisture changes Framing unattractive (must be covered)

6.1 WOOD LIGHT FRAME CONSTRUCTION - AN OVERVIEW

6.1 WOOD LIGHT FRAME CONSTRUCTION - AN OVERVIEW 6.2 INTRODUCTION TO BALLOON FRAME AND PLATFORM

FRAME 6.3 BALLOON FRAME 6.4 PLATFORM FRAME - ADVANTAGES AND

DISADVANTAGES 6.5 EIGHT STEPS FOR BUILDING A LIGHT WOOD FRAME

STRUCTURE

6.2 INTRODUCTION TO BALLOON FRAME AND 6.2 INTRODUCTION TO BALLOON FRAME AND PLATFORM FRAMEPLATFORM FRAME

Advantages: Flexible - Any shape can be constructed - Has evolved over Flexible - Any shape can be constructed - Has evolved over 150 years - Easily and swiftly constructed by hands, with a minimum amount 150 years - Easily and swiftly constructed by hands, with a minimum amount of toolsof tools

Deficiencies: Rapid burning during fire - Decays fast exposed to dampness Rapid burning during fire - Decays fast exposed to dampness - Expands and contacts significantly, causing cracking of plaster, sticking of - Expands and contacts significantly, causing cracking of plaster, sticking of doors, buckling of floors, etc. - Can be controlleddoors, buckling of floors, etc. - Can be controlled

Two types: Balloon frame andand Platform frame - - Advantages and Advantages and disadvantagesdisadvantages

Conventional Platform Frame - Built with 2” (nominal size) Built with 2” (nominal size) members - connected with nails - Lumber aligned horizontally and vertically members - connected with nails - Lumber aligned horizontally and vertically and covered with sheathing - Floors and walls constructed - Sloping roof built and covered with sheathing - Floors and walls constructed - Sloping roof built with header at lower edge and ridge boards at the the topwith header at lower edge and ridge boards at the the top

6.3 BALLOON FRAME6.3 BALLOON FRAME

In 1865, G.E. Woodward wrote ”A man and a boy can now attain the In 1865, G.E. Woodward wrote ”A man and a boy can now attain the same results, with the ease, that twenty men could on an old-fashioned same results, with the ease, that twenty men could on an old-fashioned frame… the balloon frame can be put up for forty percent less money frame… the balloon frame can be put up for forty percent less money than the mortise and tenon frame”than the mortise and tenon frame”

Framed solely with slender, closely spaced wooden members - Joist for Framed solely with slender, closely spaced wooden members - Joist for floors, studs for walls, and rafters for sloping roofs - Heavy beams were floors, studs for walls, and rafters for sloping roofs - Heavy beams were eliminatedeliminated

The full length studs ran continuously for two stories from foundation to The full length studs ran continuously for two stories from foundation to roof; hence not efficient for erection - The tall hollow spaces, in roof; hence not efficient for erection - The tall hollow spaces, in between the studs, acted as multiple chimneys, spreading the fire very between the studs, acted as multiple chimneys, spreading the fire very rapidly to upper floorsrapidly to upper floors

6.3 Balloon Framing 6.3 Balloon Framing (Cont’d)(Cont’d)

““All” Light Wood FramingAll” Light Wood Framing

Full Length StudsFull Length Studs

Cost - Less than TimberCost - Less than Timber DisadvantagesDisadvantages

– Full length studs difficult to handleFull length studs difficult to handle

– Hang 2nd floor platformHang 2nd floor platform

– No firestopNo firestop

6.4 PLATFORM FRAME WITH ADVANTAGES AND 6.4 PLATFORM FRAME WITH ADVANTAGES AND DISADVANTAGESDISADVANTAGES

Evolved from balloon frame after many modificationsEvolved from balloon frame after many modifications Accepted now as the universal standard for wood light frame constructionAccepted now as the universal standard for wood light frame construction Complex in details, but simple in conceptComplex in details, but simple in concept A floor platform is built, made up of either of a concrete slab on-ground or A floor platform is built, made up of either of a concrete slab on-ground or

with masonry/concrete footings - Wood load-bearing walls are erected upon with masonry/concrete footings - Wood load-bearing walls are erected upon this floor/footings - A second floor wood platform is built on these walls - this floor/footings - A second floor wood platform is built on these walls - Then a second set of walls is built on this platform - The attic and roof are Then a second set of walls is built on this platform - The attic and roof are then built upon the second set of walls - Many variations are possible; one or then built upon the second set of walls - Many variations are possible; one or two stories tall, several types of roof (with or without attic) can be builttwo stories tall, several types of roof (with or without attic) can be built

AdvantagesAdvantages:: Uses short, easily handled lengths of lumber for the vertical Uses short, easily handled lengths of lumber for the vertical framing - Vertical hollow spaces are automatically fire-stopped at each floor framing - Vertical hollow spaces are automatically fire-stopped at each floor levellevel

6.4 Platform Frame6.4 Platform Frame (cont’d)(cont’d)

AdvantagesAdvantages Short, easily handled lumberShort, easily handled lumber Made entirely of 2” lumberMade entirely of 2” lumber Automatic fire stopAutomatic fire stop Working platformsWorking platforms Nail ConnectionsNail Connections

Disadvantage -Vertical shrinkageDisadvantage -Vertical shrinkage

Disadvantages: Each floor constitutes of a thick layer of wood, whose grain Each floor constitutes of a thick layer of wood, whose grain runs horizontally - Leads to relatively large amount of vertical shrinkage in the runs horizontally - Leads to relatively large amount of vertical shrinkage in the frame, as moisture dries from the wood - Can lead to distress in exterior/interior frame, as moisture dries from the wood - Can lead to distress in exterior/interior finish surfacesfinish surfaces

A conventional frame built entirely of 2” members (1A conventional frame built entirely of 2” members (111//22 ” actual), with all ” actual), with all connections made with nailsconnections made with nails

Number of framing lumber are aligned parallel to one another, and nailed to cross Number of framing lumber are aligned parallel to one another, and nailed to cross pieces; then covered with a sheathing (made up of a facing layer of boards, or pieces; then covered with a sheathing (made up of a facing layer of boards, or panels) that join and stabilize the pieces into a single structural unit - In a wall panels) that join and stabilize the pieces into a single structural unit - In a wall structure, the vertical parallel pieces are structure, the vertical parallel pieces are called the studs, the cross pieces at the , the cross pieces at the bottom are the bottom are the sole plates, and the cross pieces on top are called the , and the cross pieces on top are called the top platestop plates

In a floor, the parallel pieces are In a floor, the parallel pieces are floor joists, and the cross pieces at the ends are , and the cross pieces at the ends are called called headers, rim joists, or band joists. Sheathing on floor is called . Sheathing on floor is called sub-floorsub-floor

In a sloping roof, the rafters are headed off by the In a sloping roof, the rafters are headed off by the top plates at the lower edges of at the lower edges of the roof and by the the roof and by the ridge board at the peak at the peak

6.4 PLATFORM FRAME6.4 PLATFORM FRAME ….. ….. (Cont’d)(Cont’d)

6.5 Building Sequence6.5 Building Sequence

Plan / Design the FacilityPlan / Design the Facility– Establish Use, Owner Preference, Budget Establish Use, Owner Preference, Budget

– Consider Codes, Zoning & other Legal RequirementsConsider Codes, Zoning & other Legal Requirements

– Graphically Communicate Building Design Graphically Communicate Building Design » Foundations DesignFoundations Design

» Framing plans (identifies & locates framing members)Framing plans (identifies & locates framing members)

» Architectural Floor Plans (locations, dimensions, walls, etc)Architectural Floor Plans (locations, dimensions, walls, etc)

» Exterior Elevations (details, openings, heights, finishes, etc.)Exterior Elevations (details, openings, heights, finishes, etc.)

» Interior Elevations & Sections (construction details, finishes, etc.) Interior Elevations & Sections (construction details, finishes, etc.)

» Heating & AC, Plumbing, ElectricalHeating & AC, Plumbing, Electrical

6.5 EIGHT STEPS FOR BUILDING A WOOD LIGHT 5 EIGHT STEPS FOR BUILDING A WOOD LIGHT FRAME STRUCTURE FRAME STRUCTURE (Cont’d)(Cont’d)

Step 1: Establishing the position, shape, and size of the building on site - Erecting the batter boards, beyond the area to be excavated - Erecting the batter boards, beyond the area to be excavated - Corner stakes located with a plumb bob - Corner stakes located with a plumb bob

Step 2: Excavation and construction of the foundation and substructure walls - Excavating the foundations - Excavating the foundations - Form work built for walls- Form work built for walls

- Site-cast concrete foundation - Site-cast concrete foundation - Slab-on-grade or other - Slab-on-grade or other

- 4” layer of crushed stone, 3” to 4” thick concrete - 4” layer of crushed stone, 3” to 4” thick concrete - drainage for foundation- drainage for foundation - Wall keyed to the floor slab- Wall keyed to the floor slab - Independent spread footings- Independent spread footings

Foundation Wall SystemsFoundation Wall Systems

Concrete or CMU Wall

Stone for

Drainage

Perforated Drainage

Pipe

Drainage Stone under SOG

often w/ Vapor Barrier

Damp-proofing

Concrete Strip

Footing

Sill

Anchor

Thickened Slab-on-GradeThickened Slab-on-Grade

Thickened SOG

Stone Base

Load

Damp-proofing, Protection Board, & Drainage

Sequenced Photos of a Home Under Construction

Foundation

Foundation MaterialsFoundation Materials

Reinforced Concrete Concrete Masonry Units

Vapor Barrier

Granular SubBase

Foundation InsulationFoundation Insulation

Insulate the Crawl SpaceInsulate the Crawl Space– Attach to Platform or on GroundAttach to Platform or on Ground

– Vapor BarrierVapor Barrier

Insulate the Exterior of the WallInsulate the Exterior of the Wall– Insulation exposed to the elementsInsulation exposed to the elements

Insulate the Interior of the WallInsulate the Interior of the Wall– Space & condensation considerationsSpace & condensation considerations

Insulation within the Wall (CMU)Insulation within the Wall (CMU)

6.5 EIGHT STEPS ……….6.5 EIGHT STEPS ………. (Cont’d)(Cont’d)

- Concrete wall built- Concrete wall built - Interior steel pipe columns- Interior steel pipe columns - Exterior foam insulation for frost protection- Exterior foam insulation for frost protection - Batt insulation over plastic moisture barrier in crawl space in basement- Batt insulation over plastic moisture barrier in crawl space in basement - Drainage for walls- Drainage for walls

Step 3: Making the ground floor platform - Floor framing plan- Floor framing plan - Fire place and stair case opening- Fire place and stair case opening - Double header and trimmer joists at floor openings- Double header and trimmer joists at floor openings - Bridging at mid-span- Bridging at mid-span - Plywood sheets laid with their length directions perpendicular to joists- Plywood sheets laid with their length directions perpendicular to joists - Joining details- Joining details

Step 4: Framing of the ground floor walls - Wall framing details- Wall framing details

Building Sequence - Step ThreeBuilding Sequence - Step ThreeErecting the Platform FrameErecting the Platform Frame

ConsiderationsConsiderations

– Attachment Attachment to the to the FoundationFoundation

– Floor Floor FramingFraming

– SheathingSheathing

Attachment to the FoundationAttachment to the Foundation

Sill MaterialSill Material– Decay ResistantDecay Resistant

Termite Shield Termite Shield Sill AttachmentSill Attachment

– Anchor BoltsAnchor Bolts– Expansion BoltsExpansion Bolts– Add’l for Wind / QuakeAdd’l for Wind / Quake

Set to Line & ElevationSet to Line & Elevation

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Floor FramingFloor Framing - - Spacing & SplicingSpacing & Splicing

SpacingSpacing– Factors Influencing Joist Spacing:Factors Influencing Joist Spacing:

» Floor Loading (Floor Loading (Minimums in CodeMinimums in Code) & Span Length ) & Span Length

» Strength of Joist Material UsedStrength of Joist Material Used

» Sheathing (strength & size)Sheathing (strength & size)

– Designation - Inches “o.c.” (on center)Designation - Inches “o.c.” (on center)» Typical - 16” oc (Other Typ. Options - 12” or 24”)Typical - 16” oc (Other Typ. Options - 12” or 24”)

SplicingSplicing a) In - Linea) In - Line (w/ metal strap or wood)(w/ metal strap or wood) b) Lappedb) Lapped

Floor Framing MaterialFloor Framing Material

I-Beams

2” Material(larger sizes optional)

TrussesWood, Metal, orCombination

Floor Framing Floor Framing Bridging & AnchorageBridging & Anchorage

Joist Hanger•Metal - Sized to Joist•Purpose

Anchorage & Support

Bridging•Material - Wood or Metal•Purpose:

Improve RigidityHold Joist Straight &Distribute Loads

•Code requires for joists > 2x12

Wall Framing Layout Wall Framing Layout Framing Member Size & SpacingFraming Member Size & Spacing

Loads - Vertical & LateralLoads - Vertical & Lateral– Floor Loads, # of Stories, Roof Loads, Wind, QuakeFloor Loads, # of Stories, Roof Loads, Wind, Quake– Minimum - Code RequirementsMinimum - Code Requirements

Attachment of:Attachment of:– Exterior and Exterior and – Interior FinishesInterior Finishes

Opening Locations - Doors & WindowsOpening Locations - Doors & Windows Insulation Requirements Insulation Requirements (may elect to use ‘deeper (may elect to use ‘deeper

framing to accommodate thicker insulation)framing to accommodate thicker insulation)

Framing TerminologyTop Plate -

Often Doubled

Header

Sole Plate

Sheathing

Stud

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Constructing the Wall FramingConstructing the Wall Framing

Build on the Platform & Tilt-up orBuild on the Platform & Tilt-up or Build in PlaceBuild in Place

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Wall Framing

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Step 5: Building the upper-floor platform - Details of second floor platform- Details of second floor platform

- Interior stairways- Interior stairways

Step 6: Framing of the second-story walls - Reinforcing against uplift- Reinforcing against uplift

Step 7: Framing of the attic floor and roof - Roof framing and details- Roof framing and details - Chimney details- Chimney details - Dormer- Dormer - Hip rafter- Hip rafter - Roof framing- Roof framing

Step 8: Completing the overall building frame

6.5 EIGHT STEPS ……….6.5 EIGHT STEPS ………. (Cont’d)(Cont’d)

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Wall SheathingWall Sheathing Materials:Materials:

– Typically – OSB or Plywood Typically – OSB or Plywood – Insulating Sheathing - Insulating Sheathing - (no structural qualities)(no structural qualities)

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Sheathing Purposes:Sheathing Purposes:

Joins & stabilizes the structureJoins & stabilizes the structure Resists upliftResists uplift Resists wracking- Resists lateral forcesResists wracking- Resists lateral forces Provides surface for finish materialProvides surface for finish material

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Roof Framing Built-in-Place Roof Framing Built-in-Place

Ridge BoardRafters

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Collar Ties

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Lookouts

Gable Framing

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Note Strand Orientation

Hurricane Clip

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Roof ProfilesRoof Profiles

Flat RoofFlat Roof

Single PitchSingle Pitch

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Roof ProfilesRoof Profiles

Gable RoofGable Roof

Hip RoofHip RoofHip

Ridge

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Siding