welcome to western red cedar lumber grading · slide 2 wrc lumber grading lumber grading items nlga...
TRANSCRIPT
Slide 1
Welcome toWestern Red Cedar
Lumber GradingPresented by
Rob Johnson
Slide 2
WRC Lumber Grading Lumber Grading ItemsNLGA Clear Bevel SidingNLGA Clear Finish and PanelingNLGA Knotty Paneling and SidingWRCLA Clear DeckingWRCLA Knotty Decking Inland BoardsAppearance TimbersExam Questions
Slide 3
Coastal Log Grade ZonesClear Zone - Appearance: Clear Bevel Siding, Clear
Finish and Panelling, Clear Decking (most valuable zone)
Factory Zone - Cutting Qualities:
Flitches and Shop Lumber
Construction Zone: Knotty Decking, Knotty
Bevel Siding, Knotty Panelling, Inland Boards
Slide 4
Sections of the Tree
Roots: anchor the tree; absorb moisture and mineral salts. The resulting solution, called sap, passes up the trunk to the crown.
Crown:a system of branches and twigs which bear the needles. They form the crown where the sap from the roots is transformed into tree food.
Trunk:provides mechanical support for the
crown, conducts liquid materials between the roots and the crown, stores reserve food.
Slide 5
Parts of the Trunk
Pith
The trunk consists of five (5) parts The woody part is divided into Pith, Heartwood and Sapwood
sap rising up from the roots is conducted through the sapwood Between the Sapwood and the Outer Bark is the active growth layer of
the tree called the Cambium where all new cells of wood and bark originate (the main purpose of the outer layer of bark is protection)
HeartwoodSapwoodCambium
Bark
Slide 6
Sapwood vs. Heartwood Heartwooddarker in colour, infiltrated materials functions as support lower moisture content
Sapwood lighter in colour functions as a conductor of foodhigher moisture content
Slide 7
Durability of Sapwood vs. Heartwood
Sapwood in a living tree is rarely attacked by fungus
Heartwood in the living tree, however, is more susceptible to attack
Slide 8
Annual Rings the two layers of bands, the springwood and
summerwood, together make up what is called an “annual ring”
one annual ring represents one year’s growth
Slide 9
Springwood the layer of wood cells put on
by the tree during the spring rapid growth forms wood cells
with large cavities and thin walls
appear as lighter coloured bands
Slide 10
Summerwood the layer of wood cells put on by the
tree later in the season slower growth forms wood cells with
small cell cavities and thick cell walls appear as darker
coloured bands
Slide 11
Summerwood vs Springwood
the summerwood cellsare thick-walled and therefore stronger and denser than the thin-walled springwood cells
a guide to strength and density is the amount of summerwood present
Slide 12
Rate of Growth
used to describe the relative width of growth rings
rate of growth requirements are sometimes part of a grading rule
Slide 13
Cell Structure tiny hollow longitudinal cells
running parallel to the length of the trunk
in addition to the longitudinal cells there are cells that run radially from the pith to the bark called “wood rays”
wood rays comprise 7% to 10% of the total volume of wood
Slide 14
Tree and Branch Growth
A tree begins its growth in height by sending up a single shoot, (leader) the end of the growing season small buds are formed at the top of the leader (terminal bud).
Slide 15
Tree and Branch Growth
Year after year the growth in height will be from the terminal budand the length of the branches (twigs) from the buds at the ends.
Slide 16
Knot Formation and Quality
• Sound - show no indication of unsound wood. It may be natural colour or black(not necessarily intergrown.)
• Unsound - contains decay• Tight - so fixed by growth, shape or position that it will retain its place in the
piece.
Slide 17
Knot Quality
Sound - show no indication of unsound wood. It may be natural colour or black (not necessarily intergrown.)Unsound - contains decayTight - so fixed by growth, shape or position that it will retain its place in the piece.
Sound and Tight
Encased
Unsound
Slide 18
Grain the fibres in wood and their direction, size,
arrangement, appearance or quality
Slide 19
Wood GrainWood GrainVertical Grain
Flat Grain
DiagonalGrain
Forms of KnotsForms of KnotsRound Knot
Oval Knot
Spike Knot
Slide 20
Spiral Grain and Slope of GrainSpiral Grain caused when tree fibres
take a spiral course around the trunk
edge of the piece
Slope of Grainin lumber, the deviation of the line of fibres from a straight line parallel to the sides (edges) of the piece
Slide 21
Intended Uses of Grades Clears - graded for their
attractive features (appearance)
Construction lumber is graded for strength and tight construction when sawing for strength
items, lumber should be produced as flat grain
Slide 22
WRC Clear Bevel SidingNLGA Para. 201-201E
Grade Names
Clear V.G. Heart
A
Rustic
Basic Size 6” x 12’ 6” x 12’ 6” x 12’
Faces Graded
Surfaced Face Surfaced Face Rough Face
Knots Not Permitted 1 S&T Knot = 3/4” ave. dia.
4 S&T Knots = 3/4” ave. dia.
Sapwood Not Permitted Any Amount Any Amount
Slide 23
WRC Clear Bevel Siding - Head lap
Plain Bevel – 1” head lap Rabbeted Bevel – ¾” head
lap
Slide 24
Basic Size
6”
Basic size is expressedin surface units (S.U.). and is equal to 72 S.U.
Slide 25
Faces Graded – Smooth Face
Slide 26
NLGA Western Red CedarClear Bevel Siding
Grade names:Clear V.G. HeartARustic – graded from rough
face
Slide 27
Angle of Grain
7½”
55/8”
Clear V.G. Heart
Pieces must present a vertical grain appearancefor ¾ of the actual width measured from the thickedge.
Slide 28
Knot measurement - average diameter of the longest dimension (A) and the narrowest dimension (B).
Knots
Slide 29
Intergrown Knot growth rings are partially or completely intergrown
on one or more faces with the growth rings of the surrounding wood
Slide 30
Loose/Not Firmly Fixed Knot not held tightly in place by growth, shape or position,
cannot be relied upon to retain its place
film of barkencompassing it
Slide 31
Encased Knot surrounded with pitch or bark and is not intergrown
with the growth rings of the surrounding wood
Slide 32
Unsound Knot a knot that contains decay
Slide 33
Star Checked Knot a knot that contains seasoning checks, usually
occurring from the pith to the edge of the knot
Slide 34
Sapwood
Clear V.G. Heart
Sapwood is not permittedanywhere on the exposedwidth.
Slide 35
NLGA WRC Clear Bevel SidingReview Basic Size? Normal “head lap”? Faces graded? Knots are measured? Purpose Intended? Sapwood permitted in
“Clear VG Heart”?
6” x 12’ = 72 S.U. 1” Surfaced face Average Diameter Appearance No
Slide 36
Slide 37
Clear Finish/PanelingNLGA - Para. 200 - 200CGrade Names Clear Heart A B Basic Size 8” x 12’ 8” x 12’ 8” x 12’ Faces Graded Best Face Best Face Best Face Knots - 2 - 3/4” S&T 4 - 1” Sapwood - Permitted Permitted
Cutout - - 3” - 3’ - 12’ lgr
Slide 38
Basic Size
8”Basic size is expressedin surface units (S.U.).
4”
Finish and Panelling Drop Siding and Ceiling
Slide 39
Faces Graded
5” & narrower 6” and wider
Finish
Panelling and Ceiling
Slide 40
Sapwood
sapwood
sapwoodheartwood
Slide 41
Knot measurement - average diameter of the longest dimension (A) and the narrowest dimension (B).
Knots
Slide 42
Wane bark or lack of wood from any cause, except eased
edges, on the edge or corner of a piece of lumber
Slide 43
Wane
Basic Wane EquivalentWider
EquivalentLonger
Slide 44
Cut Out
3”
Slide 45
NLGA WRC Clear Finish and Panelling - Review
Basic Size? Knots are measured? Purpose Intended? Sapwood in “Clear Heart”? Faces graded - Panelling? Faces graded - 1”x6” Finish? Faces graded - 1”x4” Finish?
8” x 12’ = 96 S.U. Average Diameter Appearance No Patterned face Best face + 1 edge Best face + both edges
Slide 46
Slide 47
Knotty Paneling/SidingNLGA Rules - Para. 204-204B
Grade Names Select Quality Faces Graded - Panelling Best or patterned face
Faces Graded - Siding Sawn or Textured face
S & T Knots Permitted Permitted
NFF/Unsound Knots Not Permitted 1” - 2 / 12’
Spike Knots 1/2 Actual Width Equivalent
Cutout Not Permitted 3” - 3’- 12’ & longer
Slide 48
NLGA Western Red CedarKnotty Panelling and Siding
Grade names:Select Knotty.Quality Knotty.
Faces Graded:Panelling – Patterned Face.Bevel Siding – Rough Face
Slide 49
Knot measurement - average diameter of the longest dimension (A) and the narrowest dimension (B).
Knots
Slide 50
Spike Knots Spike knots are measured between lines parallel to the
edges.
Slide 51
Cut Out
3”
Slide 52
NLGA WRC Knotty Panelling and Siding - Review
Knots are measured? Basic Size? Faces graded - Panelling? Faces graded - Siding? Spike knots - Select Knotty? Cutout in Quality Knotty? Purpose Intended?
Average diameter None Patterned face Rough face 1/2 actual exposed width 3” / 3’ / 12’ & longer Appearance & Weather
resisting qualities
Slide 53
Slide 54
Specifying WRCLA Cedar Decking WRCLA grade categories of decking provide a choice of clear grades
(WRCLA Clear Decking) or rustic knotty grades (WRCLA Knotty Decking) for outdoor decks of any style and budget
Slide 55
WRCLA Clear DeckingGrade Names Architect Clear Custom Clear
Faces Graded Patterned face and corresponding 1/2 edge
Basic Size 8” x 12’ 8” x 12’
Knots Two, 3/4”, S & T (per basic size)
Three, 1” S & T Four, 1/2” NFF or Unsound (per basic size)
Slide 56
WRCLA Clear Decking Thickness classifications:2” and Under thicknesses3” and 4” thicknesses
Grade names:Architect Clear DeckingCustom Clear Decking
Slide 57
Faces Graded All sizes and all grades are graded from the
patterned face and corresponding ½ of edges.
Patterned face½ of edge
½ of edge
Slide 58
Basic Size8”
Basic size is the size of a piece onwhich a specific number ofirregularities are permitted.
A standard basic sized piece is 8” x 12’.
Slide 59
Knot measurement is by average diameter of the longest dimension (A) and the narrowest dimension (B).
Knots
Slide 60
WRCLA Clear Decking Review
Grade names?
Basic size? Knots are measured? Faces graded?
Purpose Intended?
Architect Clear and Custom Clear
8” x 12’ = 96 S.U. Average diameter Best face and corresponding
1/2 edges Appearance
Slide 61
Slide 62
WRCLA Knotty Decking
Grade Names Architect Knotty Custom Knotty
Faces Graded Patterned face and corresponding 1/2 edge
Knots S & T 4” Widths = 11/2” 6” Widths = 2”
4” Widths = 2” 6” Widths = 2-7/8”
Unsound or NFF Knots
Not Permitted 4” Widths = 1” 6” Widths = 11/2”
Slope of Grain 1 in 10 1 in 8
Reverse Face Wane
1/3T, 1/4W, Full Length
1/3T, 1/3W, Full Length
Slide 63
WRCLA Knotty Decking
Grade names:Architect Knotty.Custom Knotty.
Slide 64
Faces Graded All sizes and all grades are graded from the
patterned face and corresponding ½ of edges.
Patterned face½ of edge
½ of edge
Slide 65
Knot measurement is by average diameter of the longest dimension (A) and the narrowest dimension (B).
Knots
Slide 66
WRCLA Knotty Decking Review
Grade names?
Knots are measured? Faces graded?
Purpose Intended?
Architect Knotty and Custom Knotty
Average diameter Best face and corresponding
1/2 edges Strength and Appearance
Slide 67
Slide 68
Inland Boards - WWPA Para. 30.12 – 30.14
Grade Names #2 Common #4 Common
Faces Graded Best Face
Knots - S & T Permitted Permitted
Knots - NFF or Unsound
Not Permitted Approximately 2/3 Actual Width
Spike Knots Equivalent Equivalent
Wane Face: None Allowed Back – 1/2T, 1/6W, 1/3L
On Face: 1/2T, 1/8W, 1/6 L Heavy on Back
Slide 69
WWPA Inland Boards
Grade names:#2 Common#5 Common
Slide 70
Faces Graded Grade is determined from the best face,
regardless of dressing.
Slide 71
Round Knot produced when the limb is cut at approximately
right angles to the length of its axis
found on flat grainsurfaces
Slide 72
Oval Knot produced when the limb is cut at slightly more
than right angles to the length of its axis
found on angledgrain surfaces
Slide 73
Spike Knot produced when the limb is cut either lengthwise
or diagonally to the length of its axis
found on vertical grain surfaces
Slide 74
Knot Measurement in BoardsA
B
A
B
BA
Round or Oval Knot Spike Knot
Irregular Knot Spike Knot
Slide 75
Wane
#2 Common 1” x 8” x 6’
Basic Wane EquivalentWider
EquivalentLonger
Slide 76
WWPA Inland Boards Review
Grade names? Knots are measured? Faces graded? Purpose Intended? Wane allowed on the
face in #2 Common?
#2 Common and #5 Common Average diameter Best face Construction No
Slide 77
Slide 78
Appearance TimbersGrade Names Appearance Builders Grade Faces Graded All Faces All Faces
Slope of Grain 1 in 6 1 in 4
Wane 1” across corner, ¼ Length (max 1-1/2”)
1” across corner F.L. additional 2” for 1/4 Length
S & T Knots 3” 3-1/2”
NFF/Unsound Knots
One 2” per 4’ or equivalent
3-1/2”
Slide 79
Faces Graded Graded from ALL faces and both ends. The worst or most serious characteristic
determines the grade.
Slide 80
Slope of Grain
edge of the piece
Slide 81
Slope of Grain A term used to express the amount of deviation of
the wood fibres from a line parallel to the edges of a piece.
The deviation is expressed as a ratio (i.e. 1 in 10,1 in 8).
Illustration shows slope of grain of 1 in 4
24”
6”
Slide 82
Appearance Timbers
Grade names:Appearance GradeBuilder’s Grade
Slide 83
Round and Oval Knots
Average the size on worst face. The number of knots is not controlled.
Slide 84
Appearance Timbers - Review
Knots are measured? Purpose Intended? Faces graded?
Average diameter Strength All faces plus both ends
Slide 85
Slide 86
Pieces are LabelledThey are Categorized By Team, Number, Item, Size, and Length
B 1Clear Bevel Siding
1" x 6" - 6'Review
A 1Clear Bevel Siding
1" x 6" - 6'Review