Homework ..
CMST 102
Dr. Charner Rodgers
WOOD MATERIALS & CONSTRUCTION
Lumber
Wood construction is common for many houses throughout the world and considered to the most cost-effective and best approach for housing. Wood frame is used for approximately 90% of the houses constructed in the US.
Industry
Commodity
$270 billion/year
Consumption +50% by 2050
Timber to lumber
Manufacturing
Felling
Debarking/bucking
Headrig
Bandsawing
Resaw
Seasoning
Planing
Stamping/banding
Characteristics
Nominal 2x4
Actual 1.5x3.5
Board foot
BF Calculator: http://extension.missouri.edu/scripts/explore/g05506.asp
Grading
Factors
Dimension lumber categories
Stamps
Treated
Prevent destruction
Increase service life
Preservatives
Fire retardants
Heat treated
Pressure treated
Wood Products
MANUFACTURED WOOD PRODUCTS
Glulam
Terminology
(handout)
Fiber reinforced glulam beams
Pedestrian bridge-Norway
Todaiji temple-largest wood structure
Conceptual model
Glulam
Manufacture
Engineered Beams (composite) http://www3.telus.net/selkirk99/selkirk/Beams/beams.html
LVL beam used as kitchen counter
PSL Beam
LVL beams meet to form medallion
Joists
Save time
No special tools
Less wasteful
No warp, twist or shrink
Quick installation
Knock-out holes
Trusses and panels
Plywood and OSB
Layers of veneer with grain alternating
Glue between layers
Heated and pressed
strong in all directions
Wood Frame Construction
WOOD FRAME CONSTRUCTION
System of construction using many small and closely spaced members that can be assembled by nailing. It is the standard for U.S. suburban housing. The balloon-frame house with wood cladding, invented in Chicago in the 1840s, aided the rapid settlement of the western U.S. In North America, with its abundant softwood forests, the framed building enjoyed an extensive revival after World War II in the form of platform frames.
In platform framing, each floor is framed separately, as contrasted with balloon framing, in which the studs extend the full height of the building. Freed from the heavy timbers of the post and beam system, platform framing offers ease of construction. Carpenters first fabricate a floor, which consists of wood joists and subflooring. The floor often serves as a working platform on which the stud wall frames are fabricated in sections and then lifted into place. On top of this is placed a second floor or the roof.
The roof is formed of rafters or wood trusses. Framed structures traditionally were constructed individually at each house site; today many of the framing elements are mass-produced elsewhere and assembled on-site.
The parts and pieces…
Platform Framing
Platform Framing details
Configuration & Spacing
Studs
Load bearing walls (supporting one/multiple floors)
Nonload bearing walls
Joists
Rafters
Terms
Joist: horizontal or sloped framing member
Rafter: sloping framing member for the roof
ceiling joist
floor joist
stud
rafter
Stud: vertical framing member
“Stick built”– one piece at a time
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Wall Framing
Wood Stud Walls
2 x 4’s or 2 x 6’s
16” or 24” o.c.
Insulation
vapor barriers
Interior finish (gypsum)
Header
Sill
Cripple/Jacks
sill
header
cripple/jacks
sill cripple/jacks
stud
jack stud
bottom plate
top plate
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Plates - Horizontal members at top & bottom of studs
@ Sill
@ Wall
@ Foundation
stud
bottom plate
top plate
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Blocking
Solid piece of isolated wood (stud) placed between framing members (walls, floors, roofs).
Usually for support or attachment of something else.
blocking
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Floor Framing
Wood Joist System
Relatively small joist members (2x6, 2x8, 2 x10)
closely spread
(12”, 16”, 24” o.c)
Short spans for subflooring, underlayment and gyp-board ceilings
Bridging
Material between framing members (continuous) to evenly distribute loads
Keeps framing members from twisting
Solid blocking
Diagonal bridging
blocking
bridging
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Floor Framing
Example: joist size, orientation and
spacing for the following plan
Sample Floor Joist Span Table
Sample Floor Joist Table
Douglas Fir-Larch (lumber species)
No. 1 and No. 2 (lumber grade)
All joists are bridged
12’-0”
13’-0”
Floor Systems - Floor Projections
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Floor Systems - Floor Openings
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Floor Systems - Partition Connections
Partition parallel to joists
Partition perpendicular to joists
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Partition perpendicular to joists
Partition parallel to joists
Floor Systems - Partition Connections
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Roofs
Types and slopes
Roofs
Rafter Example:
Wood Roof Framing Table for Maximum Roof Rafter Spans
Sheathing
- material covering the framing members (roof, floor & walls)
Plywood (typically 4’ x 8’ modular sheets) roll sliced lumber
OSB (oriented strand board) reconstituted (recycled) wood
Boards (cut lumber)
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Insulating sheathing
http://www.buildingscience.com/documents/guides-and-manuals/gm-guide-insulating-sheathing
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House-wrap (Dupont Tyvek)
over paneled sheathing.
http ://www2.dupont.com/Tyvek_Weatherization/en_US/products/residential/resi_homewrap.html
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