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6. WOOD LIGHT FRAME CONSTRUCTION. LIGHT WOOD FRAMING Advantages Flexible Easily constructed Economical Disadvantages Burns rapidly, Decays if exposed.

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Presentation on theme: "6. WOOD LIGHT FRAME CONSTRUCTION. LIGHT WOOD FRAMING Advantages Flexible Easily constructed Economical Disadvantages Burns rapidly, Decays if exposed."— Presentation transcript:

1 6. WOOD LIGHT FRAME CONSTRUCTION

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3 LIGHT WOOD FRAMING Advantages Flexible Easily constructed Economical Disadvantages Burns rapidly, Decays if exposed to moisture Changes volume with moisture changes Framing unattractive (must be covered)

4 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

5 6.2 INTRODUCTION TO BALLOON FRAME AND PLATFORM FRAME Flexible - Any shape can be constructed - Has evolved over 150 years - Easily and swiftly constructed by hands, with a minimum amount of tools Advantages: Flexible - Any shape can be constructed - Has evolved over 150 years - Easily and swiftly constructed by hands, with a minimum amount of tools Rapid burning during fire - Decays fast exposed to dampness - Expands and contacts significantly, causing cracking of plaster, sticking of doors, buckling of floors, etc. - Can be controlled Deficiencies: Rapid burning during fire - Decays fast exposed to dampness - Expands and contacts significantly, causing cracking of plaster, sticking of doors, buckling of floors, etc. - Can be controlled and - Advantages and disadvantages Two types: Balloon frame and Platform frame - Advantages and disadvantages Built with 2 (nominal size) members - connected with nails - Lumber aligned horizontally and vertically and covered with sheathing - Floors and walls constructed - Sloping roof built with header at lower edge and ridge boards at the the top Conventional Platform Frame - Built with 2 (nominal size) members - connected with nails - Lumber aligned horizontally and vertically and covered with sheathing - Floors and walls constructed - Sloping roof built with header at lower edge and ridge boards at the the top

6 6.3 BALLOON FRAME 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 frame… the balloon frame can be put up for forty percent less money than the mortise and tenon frame 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 frame… the balloon frame can be put up for forty percent less money than the mortise and tenon frame Framed solely with slender, closely spaced wooden members - Joist for floors, studs for walls, and rafters for sloping roofs - Heavy beams were eliminated Framed solely with slender, closely spaced wooden members - Joist for floors, studs for walls, and rafters for sloping roofs - Heavy beams were eliminated The full length studs ran continuously for two stories from foundation to roof; hence not efficient for erection - The tall hollow spaces, in between the studs, acted as multiple chimneys, spreading the fire very rapidly to upper floors The full length studs ran continuously for two stories from foundation to roof; hence not efficient for erection - The tall hollow spaces, in between the studs, acted as multiple chimneys, spreading the fire very rapidly to upper floors

7 6.3 Balloon Framing (Contd) All Light Wood Framing All Light Wood Framing Full Length Studs Full Length Studs Cost - Less than Timber Cost - Less than Timber Disadvantages Disadvantages –Full length studs difficult to handle –Hang 2nd floor platform –No firestop

8 6.4 PLATFORM FRAME WITH ADVANTAGES AND DISADVANTAGES Evolved from balloon frame after many modifications Evolved from balloon frame after many modifications Accepted now as the universal standard for wood light frame construction Accepted now as the universal standard for wood light frame construction Complex in details, but simple in concept Complex in details, but simple in concept 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 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 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 built 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 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 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 built Advantages: Uses short, easily handled lengths of lumber for the vertical framing - Vertical hollow spaces are automatically fire-stopped at each floor level Advantages: Uses short, easily handled lengths of lumber for the vertical framing - Vertical hollow spaces are automatically fire-stopped at each floor level

9 6.4 Platform Frame (contd) Advantages Short, easily handled lumber Short, easily handled lumber Made entirely of 2 lumber Made entirely of 2 lumber Automatic fire stop Automatic fire stop Working platforms Working platforms Nail Connections Nail Connections Disadvantage -Vertical shrinkage

10 Each floor constitutes of a thick layer of wood, whose grain 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 finish surfaces Disadvantages: Each floor constitutes of a thick layer of wood, whose grain 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 finish surfaces A conventional frame built entirely of 2 members (1 1 / 2 actual), with all connections made with nails A conventional frame built entirely of 2 members (1 1 / 2 actual), with all connections made with nails 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 panels) that join and stabilize the pieces into a single structural unit - In a wall structure, the vertical parallel pieces are, the cross pieces at the bottom are the, and the cross pieces on top are called the top plates 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 panels) that join and stabilize the pieces into a single structural unit - In a wall structure, the vertical parallel pieces are called the studs, the cross pieces at the bottom are the sole plates, and the cross pieces on top are called the top plates In a floor, the parallel pieces are, and the cross pieces at the ends are called. Sheathing on floor is called sub-floor In a floor, the parallel pieces are floor joists, and the cross pieces at the ends are called headers, rim joists, or band joists. Sheathing on floor is called sub-floor In a sloping roof, the rafters are headed off by the at the lower edges of the roof and by the at the peak In a sloping roof, the rafters are headed off by the top plates at the lower edges of the roof and by the ridge board at the peak 6.4 PLATFORM FRAME ….. (Contd)

11 6.5 Building Sequence Plan / Design the Facility Plan / Design the Facility –Establish Use, Owner Preference, Budget –Consider Codes, Zoning & other Legal Requirements –Graphically Communicate Building Design »Foundations Design »Framing plans (identifies & locates framing members) »Architectural Floor Plans (locations, dimensions, walls, etc) »Exterior Elevations (details, openings, heights, finishes, etc.) »Interior Elevations & Sections (construction details, finishes, etc.) »Heating & AC, Plumbing, Electrical

12 5 EIGHT STEPS FOR BUILDING A WOOD LIGHT FRAME STRUCTURE (Contd) 6.5 EIGHT STEPS FOR BUILDING A WOOD LIGHT FRAME STRUCTURE (Contd) - Erecting the batter boards, beyond the area to be excavated - Corner stakes located with a plumb bob Step 1: Establishing the position, shape, and size of the building on site - Erecting the batter boards, beyond the area to be excavated - Corner stakes located with a plumb bob - Excavating the foundations - Form work built for walls Step 2: Excavation and construction of the foundation and substructure walls - Excavating the foundations - Form work built for walls - Site-cast concrete foundation - Slab-on-grade or other - Site-cast concrete foundation - 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

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16 Foundation 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

17 Thickened Slab-on-Grade Thickened SOG Stone Base Load

18 Damp-proofing, Protection Board, & Drainage

19 Sequenced Photos of a Home Under Construction Foundation

20 Foundation Materials Reinforced ConcreteConcrete Masonry Units

21 Vapor Barrier Granular SubBase

22 Foundation Insulation Insulate the Crawl Space Insulate the Crawl Space –Attach to Platform or on Ground –Vapor Barrier Insulate the Exterior of the Wall Insulate the Exterior of the Wall –Insulation exposed to the elements Insulate the Interior of the Wall Insulate the Interior of the Wall –Space & condensation considerations Insulation within the Wall (CMU) Insulation within the Wall (CMU)

23 6.5 EIGHT STEPS ………. (Contd) - 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

24 Building Sequence - Step Three Erecting the Platform Frame Considerations Considerations –Attachment to the Foundation –Floor Framing –Sheathing

25 Attachment to the Foundation Sill Material Sill Material –Decay Resistant Termite Shield Termite Shield Sill Attachment Sill Attachment –Anchor Bolts –Expansion Bolts –Addl for Wind / Quake Set to Line & Elevation Set to Line & Elevation

26 26 Floor Framing - Spacing & Splicing Spacing Spacing –Factors Influencing Joist Spacing: »Floor Loading ( Minimums in Code ) & Span Length »Strength of Joist Material Used »Sheathing (strength & size) –Designation - Inches o.c. (on center) »Typical - 16 oc (Other Typ. Options - 12 or 24) Splicing a) In - Line (w/ metal strap or wood) Splicing a) In - Line (w/ metal strap or wood) b) Lapped b) Lapped

27 Floor Framing Material I-Beams 2 Material (larger sizes optional) Trusses Wood, Metal, or Combination

28 Floor Framing Bridging & Anchorage Joist Hanger Metal - Sized to Joist Purpose Anchorage & Support Bridging Material - Wood or Metal Purpose: Improve Rigidity Hold Joist Straight & Distribute Loads Code requires for joists > 2x12

29 Wall Framing Layout Framing Member Size & Spacing Loads - Vertical & Lateral Loads - Vertical & Lateral –Floor Loads, # of Stories, Roof Loads, Wind, Quake –Minimum - Code Requirements Attachment of: Attachment of: –Exterior and –Interior Finishes Opening Locations - Doors & Windows Opening Locations - Doors & Windows Insulation Requirements (may elect to use deeper framing to accommodate thicker insulation) Insulation Requirements (may elect to use deeper framing to accommodate thicker insulation)

30 Framing Terminology Top Plate - Often Doubled Header Sole Plate Sheathing Stud

31 31 Constructing the Wall Framing Build on the Platform & Tilt-up or Build on the Platform & Tilt-up or Build in Place Build in Place

32 32 Wall Framing

33 33 - Details of second floor platform Step 5: Building the upper-floor platform - Details of second floor platform - Interior stairways - Interior stairways - Reinforcing against uplift Step 6: Framing of the second-story walls - 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 ………. (Contd)

34 34 Wall Sheathing Materials: Materials: –Typically – OSB or Plywood –Insulating Sheathing - (no structural qualities)

35 35 Sheathing Purposes: Joins & stabilizes the structure Joins & stabilizes the structure Resists uplift Resists uplift Resists wracking- Resists lateral forces Resists wracking- Resists lateral forces Provides surface for finish material Provides surface for finish material

36 36 Roof Framing Built-in-Place Ridge Board Rafters

37 37 Collar Ties

38 38 Lookouts Gable Framing

39 39 Note Strand Orientation Hurricane Clip

40 40 Roof Profiles Flat Roof Flat Roof Single Pitch Single Pitch

41 41 Roof Profiles Gable Roof Gable Roof Hip Roof Hip Roof Hip Ridge

42 42 Siding


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