Bark
Outermost protective layer of tree
Cambium Layer
New wood cells in tree
Sapwood
living cells that store and transport nutrients
Heartwood
dead cells that contribute to structural strength
pithe
first years growth, innermost layer
Softwoods
cone bearing trees
simple cells structure
N/A forests
Hardwoods
harvested around the world
FSC (Forest Stewardship Council)
only certified org. recognized by LEED certification
Sawing
first stage in lumber production
Plainsawn
growth rings parallel to wide face of board
Quartersawn
growth rings perpendicular to wider face of baord
Quartersawn
narrow spaced grain pattern on wider face
Ritesawn
angle of grain falls perfectly between plainsawn and quaretrsawn
Seasoning
second step in lumber production
Seasoning
drying lumber after it is sawn
Below 20%
Decay fungi cant live with MC content:
Below 30%
Wood shrinks after the MC content:
diff between tangential and radial shrinkage
causes distortions in lumber shape
EMC (Equilibrium Moisture Content)
when wood dries equal to air
15-19%
EMC content for exterior uses:
5-11%
EMC content for interior uses
Surfacing
third stage in lumber production
Surfacing
making lumber smooth and of perfect dimensions
framing lumber
(S4S)
type of surfacing on 4 sides
finishing lumber
(S4S or S2S)
four sides surfaced, or two sides and the other two left for woodworker
surfacing after seasoning
(S-Dry)
removes some drying distortions
surfacing after seasoning
(S-GRN)
more economical
better for wood that doesnt excessively distort
construction planking
unsurfaced
results in stronger plank bc no material is removed
more slip resistant
Structural Grading
way of rating lumber
higher ratings means less defects
performed visually or machines
Appearance Grading
way of rating lumber
for extent defects (knots)
always visually
Compression and Tension
Wood has good strength in:
less
Actual sizes are ___________ than normal sizes in lumber
3/4" x 3.5"
1.5" x 3.5"
1.5" x 9.25
Actual dimensions of a 1x4? 2x4? 2x10?
sometimes stronger and stiffer
Manufactured wood products are __________
Nominal
(by board foot)
In US, we price lumber by nominal or actual sizes?
Glue Laminated Wood
readily available wood that can be curved
uses high grade pieces ONLY at points of high stress
1. Laminated Strand Lumber and Oriented Strand Lumber
(LSL) (OSL)
2. Laminated Veneer Lumber (LVL)
3. Parallel Strand Lumber (PSL)
List in order by increasing strength the 3 structural composite lumber products?
beams and headers
what are structural composite lumber used for?
headers
short beams over openings
Wood-Plastic Composties
less stiff and greater thermal expansion than solid lumber
Plastic Lumber
(aka Wood plastic composite)
greater than 50% plastic
1. Plywood
2. Composite Panels
3. Oriented Strand Board
4. Particleboard
5. Fiberboard
List 5 Structural Wood Panels
4x8'
5/16"
1 and 1/8" thick
standard sizes of structural wood panels
sheathing and subflooring
Structural Wood Panels used for:
exposure 1
most common durability classification
1. Fire-retardent Wood
2. Preservative Treated Wood
2 types of chemically treated wood
1. Nails
2. Screws
3. Bolts
3 types of wood fasteners
Bolts
require pre-drilled hole
screws
_________ CAN require pilot holes
screws
require more time but hold better than nails
trusses
type of manufactured wood products
lightweight, joined with tooth plates
I-Joists
raw material
type of manufactured wood product
span further than solid lumber
uses less ___________
Panel Components
type of manufactured wood product
act structurally or attached to frame
1. Manufactured Homes (Mobile Homes)]
built to HUD standard
2. Modular Construction
factory
2 types of factory built housing
1. built to ________ ______
2. built in ______ and trucked to site