thick layer of living wood cells inside cambium

-distributes sap upward

wood from coniferous trees

-simpler microstructure made mostly of large tracheids and small number of rays

wood from broadleaf trees

-more complex in structure

-larger percentage of rays

-fibers and pores transport sap

plainsawn

(flatsawn)

 wood dividing method that produces maximum yield

-tends to warp during seasoning, vary in surface appearance, erode quicker

-structural use

quartersawn

(rift or edge sawn)

sawing method that produces edge grain but with more waste of slab(more $)

-growth rings perpendicular to wider face of board

-withstands moisture, weathering, paint

-flooring, trim, furniture

EMC

moisture content of wood expected in the completed, conditioned building

shrinkage in the radial direction

-larger than longitudinal

shrinkage around the circumference of the log

-greater than radial and longitudinal

discontinuities in structure from tree itself

-knots(branch joins tree trunk)

-knotholes(loose knots dropping out of wood)

-decay

-insect damage

discontinuities in lumber caused at the mill

-difference in shrinkage

-different grain orientation

crooking

bowing

cupping

lumber sizes given in US

-different from actual size due to sawing, seasoning, surfacing

-2x10 becomes 1.5x9.25

glue laminated wood

(glulam)

joining many smaller strips of wood together with glue

-used for size, shape, quality

structural composite lumber

(engineered lumber)

Laminated stand lumber (LSL)

and 

Oriented strand lumber (OSL)

wood fibers and plastics of various types, mixed with other ingredients which are then heated and pressed into a final form

-decking, railing, trim

lumber like products with a plastic content of 50% or more

-also recycled plastic lumber RPL

structural grad plastic lumber

SGPL

at least as strong as conventional solid wood

-less stiff, more prone to long term creep under permanent loads

-oriented strand board OSB

-Particle board

-fiberboard

oriented strand board

OSB

waferboard

smaller particles than OSB

-underlayment panel

fine grained board made from wood fibers and synthetic resin binders

-interior only

-MDF

medium density overlay

or

high density overlay

plywood

load tested

-permits use of many types of woods and panels whicle achieveing same structural purpose

made from finely recycled paper waste

-wall sheathing, acoustical isolation, carpet underlay

Fire-retardant treatment

FRT

oily derivative of coal widely used to treat wood in engineering structures

-high odor and toxicity, unpaintable

chromated copper arsenate

CCA

waterborne salt wood preservative

-toxicity, phased out of residential and commercial building

Alkaline copper quat

ACQ

and

Copper Boron azoles

CBA

Sodium Borate

SBX

borate compunds, least toxic

-above ground only

common nail

and 

box nail

smaller in diameter, used to fasen finish woodwork

-less obtrusive

unit used in the US to measure nails

-abbreviated "d."

-face nailing

-end nailing

-toe nailing

large screws for structural connections

-square or hexagon heads

used mainly for structural connections in heavy timber framing

-fasten ledgers, beams, etc.

used in conjunction with bolt and inserted in matching circular grooves in matting pieces of wood

-greater capacity by spreading the load across greater area

used in factory produced lightweight roof and floor trusses

-metal splice plates, each with alrge number of built in nails

structural insulated panel

SIP

Stressed skin panel

SSP

review:

changes in moisture content and effects on dimension of lumber from time it is cut, processed, put into service in building

1. free water leaves-30% water left in tree

2.bound water leaves-shrinkage starts

3. seasoned to below 15-19% moisture

---air or kiln dried

---most shrinkage in diameter

4.wood reaches EMC

review:

plainsawn vs. quartersawn lumer:

applications for each

plainsawn:

-maximum yield; tendency to warp

--structural uses

Quartersawn:

.free water evaporates first, 30%left in tree

.bound water leaves, shrinkage starts

.seasoned to below 15-19%

.air or kiln dried

-shrinkage is greatest radially, can cause distortion

-once installed, it will react to atmospheric conditions, expanding and shrinking based on humidity

plainsawn: -max number of pieces

-tendency to warp    -varied grain patterns

.structural uses

quartersawn:  -more stable    -resists shrinkage

-resists warp   -better paint surface   -less splitting

.flooring, paint

give the actual cross sectional dimensions of the following pieces of kiln dried lumber:

1x4

2x4

2x6

2x8

4x4

4x12

3/4 x 3 1/2

1 1/2 x 3 1/2

1 1/2 x 5 1/2

1 1/2 x 7 1/4

3 1/2 x 3 1/2

3 1/2 x 11 1/4

*1-6= 1/2" off

6 ^= 3/4" off 

why: wood is laminated to achieve desired size, shape, quality that would otherwise be impossible; more efficient

products: glue laminated wood, structural composite lumber, wood plastic composites

.more versatile & available

.increased strength

.no defects

32 is the allowable span in inches between centers of rafters when used in roof sheathing

16 is the allowable span when used as subflooring

products: plywood, composite, OSB, any wood species

name the most appropriate plywood veneer grade for each of the following applications:

a. the outer face of a wall or roof sheathing panel

b. subflooring to receive a wood finish flooring

c. underlayment to receive a thin, resilient vinyl floor covering

d. plywood to receive a paint finish in an application demanding the highest quality finish

a. C or D

b. B

c. C

d. A

reasons: places where decay or insect resistance is needed(termites), marine docks, fences

alternatives: redwood, cedar heartwood