2. Light Wood Frame Construction
Chapter 5
Light Wood Frame Construction

3. Light Wood Framing Advantages Disadvantages Flexible
Easily constructed
Economical
Disadvantages
Burns rapidly,
Decays if exposed to moisture
Changes volume with moisture changes
Framing unattractive (must be covered)
Advantages
Flexible
MOST ANY SHAPE
ASSIMILATED ALL THE CHANGES - MPE
Easily constructed
MINIMAL EQUIPMENT & TOOLS
Economical
STILL COMPETITIVE WITH “FACTORY BUILT”
Disadvantages
Burns rapidly, Decays if exposed to moisture
Changes volume with moisture changes
NATURAL PRODUCT - HUMIDITY AFFECTS

4. History - Prior to mid-1800s
Timber Frame
timber with masonry
timber with earth fill
Interior walls were simple plank structure
Trees were plentiful, and labor was intense.
Craftsmen were available, but tools were limited – and had to be operated by hand.

5. History - mid 1800s Light wood framing advanced by
Development of water powered saw mills
Machine made nails became available
Earliest Version of Lt. Wood Framing
Balloon Framing
Long lengths of material was plentiful
Wood members were small & easily handled
Provided for lateral stability

6. Balloon Framing
Erection of wall framing members on a wood sill secured to the foundation and lapped against the floor joists.
Second floor joists lapped into the wall framing system.
Roof framing then set on top of wall plates. Roof rafters tied to ceiling joists secured lateral displacement of exterior walls.
Components were light in comparison to timber structures, and erection required minimal labor than before. The practice was a more efficient use of material.

7. DISADVANTAGES OF BALOON FRAMING
Long, straight lengths of material diminished in availability as more structures were built.
When buildings caught fire, the wall cavity of balloon framing allowed fire & smoke to chimney all the way to the roof, and structures burned rapidly.
Since the wall and floor structure were built integrally, most of the framing work was done off the ground, where level conditions might not exist.

8. PLATFORM FRAMING
With the disadvantages of balloon framing, the platform frame system evolved.
The floor structure was first built onto the foundation sill, then decked to provide a ‘platform’ on which to work.
Ground-floor walls were erected with a top plate to receive the second floor joists, which became a sill on which to erect the upper floor joists – which, when decked became another platform.
Single floor framing was more plentiful because of shorter lengths.

12. Building Sequence
Architect Plans and Designs the Facility – Then Prepares Design and Construction Documents
Involve a selected Contractor, who:
Obtains Building Permit
Purchases necessary materials
Selects Sub-Contractors for each phase of work
Excavation for utilities, foundations
Install Underground utility lines (electrical, plumbing)
Foundation construction
Floor Construction
Erect Framing for Structure

13. Build construction pad & set batter boards

14. Batter boards enable accurate layout of foundation

15. A transit ensures accurate angles in layout

16. A level is used to ensure proper grades & elevation

17. Excavate & Place Foundations
Materials Typically Used:
Site Cast Concrete
Concrete Masonry Units
Reinforcing Steel
Tie wire
Anchor Bolts
Foundation and Basement Wall Construction
Construction for support of loads
Damp proofing and/or perimeter insulation

18. Foundation Wall Systems
Sill Anchor
Concrete or CMU Wall
Damp-proofing
Drainage Stone under floor slab
with Vapor Barrier
Gravel for
Drainage
Perforated Drainage Pipe
Concrete grade beam

19. Utility installation is simultaneous with foundation work

20. Installation of Plumbing Drainage Piping
Underground Plumbing

21. Example of grade beam monolithic with concrete floor
Wall
Load
Granular Base
Thickened Slab on grade

22. Installation of plastic vapor barrier under concrete floor
Granular SubBase

23. Foundation Insulation
Some building codes require perimeter insulation at foundations – especially in cold climates.
Insulate the Crawl Space or Basement Walls
Attach to Platform or on Ground
Vapor Barrier

24. Building the Platform Frame in Wood Floor With Crawl Space
Sequence of Assembly
Install sills with insect barriers
Bolt sill members to the Foundation
Install floor framing and bridging
Install floor decking

26. Attachment to the Foundation
Sill Material
Treated for resistance to insects & decay in damp climates.
Install insect shields
Sill Attachment with anchor bolts

27. Floor Framing Options FRAME WITH FRAME FLOORS DIMENSION LUMBER
USING TRUSSES

28. FRAME FLOORS WITH “I” JOISTS

29. Floor Framing Spacing & Splicing
Factors that determine joist spacing:
Floor Loading & Span Length
Strength of Joist Material Used
Type & thickness of floor decking
Designation - Inches “o.c.” (on center)
Typical - 12” , 16”, or 24” – to fit standard lumber lengths)

30. Bridging for Floor Framing

31. Floor Framing Using Steel Anchors

32. Decking over Floor Framing
Materials Used
Plywood or OSB
Concrete or gypsum is poured over second floor decks for sound deadening
Installation
Deck is laid perpendicular to floor joists
End joints are staggered to brace joists
Power nails, screws, construction adhesive

33. Building Sequence for Ground Floor Walls
Layout
Sole plates installed to define wall locations
Wall Framing - Lay out studs & assemble with single top wall plate
Tilt up walls on the Platform & fasten to sole plate
Install second layer of top wall plate to tie all partitions and walls together.
Install Wall Sheathing
Corner bracing required for lateral stability – usually OSB or plywood at all exterior corners

34. Framing Terminology Top Plate - Doubled Stud Header Sheathing Decking
Sole Plate

35. Headers
Headers are beams installed over openings to carry weight of second floor or roof loads.
Sizing Factors: Load, Span, Material
Materials: dimension lumber, Laminated wood, or Steel

36. Erecting the Wall Framing
Build framing on the Platform & Tilt-up, brace, and fasten to sole plates.

37. Double Top Plate
Joist Support
Tie Framing Together

38. Double Top Plate Double Header
Header Supports

39. Corner Framing

40. Sole Plate Anchorage

41. PROVIDES THE STURCTURAL STABILITY NEED DIAGONAL BRACING W/O SHEATHING
Wall Sheathing
Materials:
OSB or Plywood for corner bracing
Insulating Sheathing - (no structural qualities)
PROVIDES THE STURCTURAL STABILITY
NEED DIAGONAL BRACING W/O SHEATHING

42. Exterior Wall Sheathing:
Joins & stabilizes the structure
Resists uplift
Resists racking & lateral forces
Provides surface for finish material

43. Building Sequence PLATFORM & 2ND Story Walls
Erect 2nd Story Platform
Similar to 1st Floor Sequence
Install 2nd Floor access (stairs)
Erect 2nd Story Walls & Sheathing

44. Building Sequence Attic Floor & Roof
Options
Build-in-place ceiling joists, rafters, and bracing, OR
Prefabricated Trusses, OR
Combination

45. Roof Framing Built-in-Place
Ridge Board
Rafters

46. Collar Ties

47. LOOKOUTS TO FORM OVERHANGS
GABLE FRAMING

48. Prefabricated Roof Trusses

49. Note Strand Orientation
Hurricane Clip

50. Metal clips in decking prevent uneven deflection

51. Roof Profiles
Flat Roof
Single Pitch

52. Roof Profiles
Gable Roof
Hip Roof
Hip
Ridge