Lesson A3–8: Selecting Lumber Selecting Lumber. Problem Area 3. Construction Systems.

Lesson A3–8:Lesson A3–8:

Selecting LumberSelecting Lumber

Problem Area 3.Problem Area 3.

Construction SystemsConstruction Systems

TerminologyTerminology Bending strengthBending strength Board feetBoard feet Common boardsCommon boards Compression strengthCompression strength Dimension lumberDimension lumber Dressed lumberDressed lumber Factory or shop lumberFactory or shop lumber Green lumberGreen lumber HardboardHardboard HardnessHardness

HardwoodHardwood Kiln-dried lumberKiln-dried lumber Linear feetLinear feet Nominal or rough lumberNominal or rough lumber PanelingPaneling Particle boardParticle board PegboardPegboard Plain sawingPlain sawing PlywoodPlywood Quarter sawingQuarter sawing

TermsTerms SeasoningSeasoning Select or finish boardsSelect or finish boards SoftwoodSoftwood StiffnessStiffness Structural lumberStructural lumber ToughnessToughness VeneerVeneer Wafer boardWafer board Worked lumberWorked lumber Yard lumberYard lumber

Student Learning ObjectivesStudent Learning Objectives

Explain how to produce and Explain how to produce and process lumber and wood products.process lumber and wood products.

Discuss the grading and selection of Discuss the grading and selection of lumber.lumber.

Explain the process of sizing, Explain the process of sizing, buying, and storing lumber.buying, and storing lumber.

Interest ApproachInterest Approach

Show samples of various sizes of Show samples of various sizes of lumber and examples of wood lumber and examples of wood products such as plywood, particle products such as plywood, particle board, and wafer board. board, and wafer board.

Ask students questions to spark their Ask students questions to spark their interest in learning about selecting, interest in learning about selecting, grading, buying, and storing lumber. grading, buying, and storing lumber.

Interest ApproachInterest Approach

What happens between cutting What happens between cutting down a tree and you buying the down a tree and you buying the wood as lumber?wood as lumber?

How is lumber graded and stored? How is lumber graded and stored? How can you determine which type How can you determine which type

of lumber to buy? of lumber to buy?

Anticipated Problem:Anticipated Problem:

How are lumber and other How are lumber and other wood products produced wood products produced

and processed?and processed?

Lumber Production and ProcessingLumber Production and Processing

After trees are cut down they are After trees are cut down they are transported to the sawmill. transported to the sawmill.

The logs are soaked until sawing The logs are soaked until sawing time to prevent checking, cracking, time to prevent checking, cracking, and warping.and warping.

Lumber Production and ProcessingLumber Production and Processing

After removing the bark, the wood is After removing the bark, the wood is cut into standard lengths and widths cut into standard lengths and widths and is referred to as lumber.and is referred to as lumber.

Logs are either plain-sawed or Logs are either plain-sawed or

quarter-sawed. quarter-sawed.

Plain-SawingPlain-Sawing

Plain sawing: Cutting the log on a Plain sawing: Cutting the log on a tangent to the growth ringstangent to the growth rings Is faster with less waste resulting in Is faster with less waste resulting in

lower cost lumber. lower cost lumber. Produces a flat or slash-grained Produces a flat or slash-grained

lumber that is used for most buildings. lumber that is used for most buildings.

(Picture Courtesy, Interstate Publishers, Inc.)

Plain-SawingPlain-Sawing

Quarter-Sawed LumberQuarter-Sawed Lumber

Quarter sawing: Cutting the log Quarter sawing: Cutting the log perpendicular to the growth ringsperpendicular to the growth rings Results in lumber less likely to warp, Results in lumber less likely to warp,

shrink, and swell.shrink, and swell. Since quarter-sawed edge or Since quarter-sawed edge or

vertical grained boards have a vertical grained boards have a prettier grain, they are often used to prettier grain, they are often used to make furniture.make furniture.

Quarter-Sawed LumberQuarter-Sawed Lumber

Drying LumberDrying Lumber

After the lumber is cut, it is ready to After the lumber is cut, it is ready to be dried. be dried.

Seasoning: Process of drying Seasoning: Process of drying lumber to the point where it is ready lumber to the point where it is ready to use. to use.

Green lumber: Freshly cut lumber Green lumber: Freshly cut lumber with 20 percent or more moisture.with 20 percent or more moisture.


Lumber can be stacked outside with Lumber can be stacked outside with spacers to allow air flow between spacers to allow air flow between layers. layers.

Air drying takes from one to three Air drying takes from one to three months and typically reduces months and typically reduces moisture content to 15 percent. moisture content to 15 percent.


Kiln-dried lumber uses a large oven Kiln-dried lumber uses a large oven or kiln to dry the lumber to 6 to 12 or kiln to dry the lumber to 6 to 12 percent moisture.percent moisture.

Starting with high steam and low Starting with high steam and low heat the kiln gradually adjusts to low heat the kiln gradually adjusts to low steam and high heat to remove steam and high heat to remove moisture without creating cracks in moisture without creating cracks in the lumber.the lumber.


After drying, the lumber in some After drying, the lumber in some cases is used rough, also referred cases is used rough, also referred to as unmilled or unplaned.to as unmilled or unplaned.

Dressed lumber is smoothed and Dressed lumber is smoothed and

given uniform dimensions by given uniform dimensions by running it through a planer.running it through a planer.

Dried and Planed LumberDried and Planed Lumber

Can be processed into a variety of Can be processed into a variety of wood products such as:wood products such as: Beveled siding,Beveled siding, Tongue-and-groove flooring, Tongue-and-groove flooring, Trim, Trim, Molding, Molding, Etc..Etc..

Plywood:Plywood:

Wood product made of a series of Wood product made of a series of plies or layers (3, 5, or 7) glued plies or layers (3, 5, or 7) glued together with the grains of adjacent together with the grains of adjacent layers arranged at right angles to layers arranged at right angles to each other to form a 4×8 sheet.each other to form a 4×8 sheet.

By gluing layers so that the grain By gluing layers so that the grain runs in opposite directions the runs in opposite directions the strength is maximized.strength is maximized.

Particle BoardParticle Board

4×8 sheet made by gluing wood 4×8 sheet made by gluing wood chips, splinter, and sawdust chips, splinter, and sawdust together.together.

Because it is hard and brittle, it is Because it is hard and brittle, it is used under countertops and in used under countertops and in some furniture.some furniture.

Particle BoardParticle Board

While particle board is cheaper than While particle board is cheaper than plywood, it needs to be cut with a plywood, it needs to be cut with a carbide-tipped blade and warps carbide-tipped blade and warps quickly when it gets wet.quickly when it gets wet.

WaferboardWaferboard

Also known as OSB board and chip Also known as OSB board and chip boardboard

Made by gluing wood chips to form Made by gluing wood chips to form 4×8 sheets.4×8 sheets.

Since it is cheaper and more water Since it is cheaper and more water resistant, wafer board is replacing resistant, wafer board is replacing plywood as roof sheathing and plywood as roof sheathing and subflooring.subflooring.

HardboardHardboard

Made by gluing wood fibers into Made by gluing wood fibers into sheets. sheets.

Since it is hard and brittle, it should Since it is hard and brittle, it should be cut with a carbide-tipped blade be cut with a carbide-tipped blade and it does not hold nails well. and it does not hold nails well. May be used as tabletops or shaped May be used as tabletops or shaped

in long boards to use as siding.in long boards to use as siding.

PegboardPegboard

Pegboard: Hardwood with a series Pegboard: Hardwood with a series of uniformly sized and shaped of uniformly sized and shaped holes. holes. Pegboard is useful as a hand tool Pegboard is useful as a hand tool

organizer. organizer. Peg-board hooks of various sizes are Peg-board hooks of various sizes are

available at most hardware stores.available at most hardware stores.

PanelingPaneling

1/8 or ¼ inch sheet of wood or 1/8 or ¼ inch sheet of wood or hardboard with a wood grain hardboard with a wood grain surface. surface.

Cheap paneling may be hardboard Cheap paneling may be hardboard with wood grain contact paper on with wood grain contact paper on the surface.the surface.

VeneerVeneer

Thin layer of material that is glued Thin layer of material that is glued to an inferior quality material. to an inferior quality material.

While high quality furniture is While high quality furniture is generally solid wood, low cost generally solid wood, low cost furniture is often particle board with furniture is often particle board with a veneer wood grain surface layer.a veneer wood grain surface layer.


How is lumber graded and How is lumber graded and selected for use?selected for use?

Lumber Grading and Selection Lumber Grading and Selection

Wood for lumber is divided into two Wood for lumber is divided into two broad categories, “softwood” and broad categories, “softwood” and “hardwood”. “hardwood”. Refers not to the hardness of the Refers not to the hardness of the

wood, but to the type of tree they wood, but to the type of tree they come from. come from.

Lumber Grading and Selection Lumber Grading and Selection

Softwood: Lumber cut from Softwood: Lumber cut from coniferous (cone-bearing) coniferous (cone-bearing) evergreen trees with needle-like evergreen trees with needle-like leaves.leaves.

Hardwood is lumber cut from broad-Hardwood is lumber cut from broad-leaved (deciduous) trees that drop leaved (deciduous) trees that drop their leaves in the fall. their leaves in the fall.

Lumber Grading and SelectionLumber Grading and Selection

Fine furniture is typically made from Fine furniture is typically made from hardwood. hardwood.

Since construction lumber is Since construction lumber is generally softwood this unit will generally softwood this unit will focus on softwood grading.focus on softwood grading.

Softwood GradingSoftwood Grading

Softwood grading is based on:Softwood grading is based on: Appearance,Appearance, Strength, or Strength, or Combination of the two. Combination of the two.


Defects which can affect both Defects which can affect both appearance and strength include:appearance and strength include: knots,knots, checks, checks, splits,splits, decay,decay, stains, stains, insect holesinsect holes


Softwood grading classifies lumber Softwood grading classifies lumber according to use: according to use: Yard lumber, Yard lumber, Structural lumber, and Structural lumber, and Factory or shop lumber. Factory or shop lumber.

Yard LumberYard Lumber

Lumber less than five inches thickLumber less than five inches thick

Used for ordinary construction and Used for ordinary construction and general building purposes.general building purposes.

Structural lumberStructural lumber Two inches or more in nominal Two inches or more in nominal

thickness and widththickness and width Stress tested and used as:Stress tested and used as:

Joists,Joists, -Beams, -Beams, Stringers,Stringers, -Posts, -Posts, Timbers, Timbers, -Truss members.-Truss members.

For the most part, it is wider and For the most part, it is wider and thicker than dimension lumber.thicker than dimension lumber.

Factory or shop lumberFactory or shop lumber

Used in:Used in: Doors,Doors, Window sashes, Window sashes, Foundry patterns, and Foundry patterns, and General cut-up purposes.General cut-up purposes.

Select or Finish BoardsSelect or Finish Boards

While blueprints may specify stress While blueprints may specify stress rated structural lumber for some rated structural lumber for some framing components, most building framing components, most building is done with yard lumber. is done with yard lumber.

Yard lumber includes select or finish Yard lumber includes select or finish boards, common boards, and boards, common boards, and dimension lumber. dimension lumber.

Select or Finish BoardsSelect or Finish Boards

Select or finish boards: Graded A Select or finish boards: Graded A through D based on appearance.through D based on appearance.

Typically one inch thick Typically one inch thick (1 × 4,1 ×6,etc.)(1 × 4,1 ×6,etc.)

Used as an inside surface to be Used as an inside surface to be coated with varnish or paint.coated with varnish or paint.

Common Boards:Common Boards:

One inch thick,One inch thick, 2 to 12 inches wide 2 to 12 inches wide Graded on a combination of Graded on a combination of

appearance and strength from appearance and strength from number 1 common to number 5 number 1 common to number 5 common.common.

Dimension Lumber:Dimension Lumber: Two to five inches thick Two to five inches thick Two inches or more wide Two inches or more wide Graded on strength and stiffness.Graded on strength and stiffness. Dimension lumber grades are:Dimension lumber grades are:

Construction, Construction, Standard,Standard, Utility, Utility, Economy, and Economy, and Economy stud. Economy stud.

Graded LumberGraded Lumber

Graded lumber will have a grade Graded lumber will have a grade mark that includes:mark that includes: Grade, Grade, Moisture content, Moisture content, Species of the tree, Species of the tree, Mill where processing was done, and Mill where processing was done, and Certification mark indicating the Certification mark indicating the

association that graded the lumber.association that graded the lumber.

PlywoodPlywood

Grade is based on the outer plies. Grade is based on the outer plies. Interior plies are grade D. Interior plies are grade D. Grade is based on the presence of Grade is based on the presence of

knots, knot holes, and surface knots, knot holes, and surface plugs.plugs.

Exterior plywood has waterproof Exterior plywood has waterproof glue glue

PlywoodPlywood

Interior plywood has only water Interior plywood has only water resistant glue.resistant glue.

Application with only one exposed Application with only one exposed surface can be graded A–D or A–C. surface can be graded A–D or A–C.

Signs and cabinets need A–A with Signs and cabinets need A–A with two good sides. two good sides.

Roof sheathing is usually Roof sheathing is usually construction grade plywood (CDX).construction grade plywood (CDX).

Selecting Grade to BuySelecting Grade to Buy

Use the lowest quality of lumber Use the lowest quality of lumber suitable for the purpose. suitable for the purpose.

Inexperienced buyers should Inexperienced buyers should depend on the advice of an depend on the advice of an experienced, reliable lumber yard experienced, reliable lumber yard employee to make grade purchase employee to make grade purchase decisions.decisions.

Matching Lumber to jobMatching Lumber to job

Requires a knowledge of the Requires a knowledge of the characteristics of each species of characteristics of each species of wood.wood.

What to look for when:What to look for when: Siding for a house:Siding for a house:

Good nailing and weather resistant qualities.Good nailing and weather resistant qualities. House framing members:House framing members:

Strength and stiffness. Strength and stiffness.


Furniture construction:Furniture construction: Attractive appearance, freedom from Attractive appearance, freedom from

blemishes and flaws, desirable wood blemishes and flaws, desirable wood grain, hardness, and resistance to grain, hardness, and resistance to warping are important.warping are important.


White woods (white pine, fur, and White woods (white pine, fur, and spruce) and yellow pine: Most spruce) and yellow pine: Most popular species used in popular species used in construction.construction.

Properties of WoodProperties of Wood Good understanding of wood Good understanding of wood

properties is essential for intelligent properties is essential for intelligent lumber selection.lumber selection.

Properties Include:Properties Include: Hardness Hardness Bending strength Bending strength Stiffness Stiffness Compression strength Compression strength ToughnessToughness

HardnessHardness

Wood is solid or firm, and will not Wood is solid or firm, and will not dent or scratch easily.dent or scratch easily.

Weight of dry wood is a good Weight of dry wood is a good indicator of its relative strength. indicator of its relative strength.

Freedom from warping and bowing Freedom from warping and bowing is important. is important.

Ease of cutting and nail-holding Ease of cutting and nail-holding power should be considered.power should be considered.

Bending StrengthBending Strength

Ability of lumber to be bent without Ability of lumber to be bent without breaking.breaking.

StiffnessStiffness

Ability of wood to resist bending Ability of wood to resist bending under load. under load.

Compression StrengthCompression Strength

Ability of a piece of lumber to resist Ability of a piece of lumber to resist being mashed or squeezed together being mashed or squeezed together by weight applied against its ends.by weight applied against its ends.

ToughnessToughness

Ability of the wood to withstand Ability of the wood to withstand sudden shock.sudden shock.

Tough wood refuses to break when Tough wood refuses to break when subjected to repeated shocks, jars, subjected to repeated shocks, jars, or blowsor blows


How is lumber sized, How is lumber sized, purchased, and stored?purchased, and stored?

Sizing, Purchasing, and Storing Sizing, Purchasing, and Storing LumberLumber

May be purchased green (over 20 May be purchased green (over 20 percent moisture), air dried, or kiln percent moisture), air dried, or kiln dried.dried.

They may be rough, dressed, or They may be rough, dressed, or worked lumber. worked lumber. Nominal, or rough lumber: Lumber as Nominal, or rough lumber: Lumber as

it comes from the saw (unplaned). it comes from the saw (unplaned).


Most lumber is planed before it is Most lumber is planed before it is sold.sold.

Planed lumber is also called:Planed lumber is also called: Surfaced,Surfaced, Dressed, and Dressed, and Milled.Milled.


The difference between nominal The difference between nominal and dressed dimensions of lumber and dressed dimensions of lumber is the result of:is the result of: Planing,Planing, Shrinkage that occurs during drying. Shrinkage that occurs during drying.


Worked lumber: Wood that has Worked lumber: Wood that has been:been: Shaped (trim), Shaped (trim), Matched (tongue-and-groove), or Matched (tongue-and-groove), or Patterned (molding).Patterned (molding).

Actual vs. Nominal DimensionsActual vs. Nominal Dimensions

Project planner uses the actual Project planner uses the actual planed dimensions (¾×3½ , planed dimensions (¾×3½ , 1½×7¼, etc.) to determine the 1½×7¼, etc.) to determine the number and length of boards number and length of boards needed needed

Nominal dimensions (2×4, 1×6, etc.) Nominal dimensions (2×4, 1×6, etc.) are used when ordering lumber. are used when ordering lumber.


Softwood nominal widths are 2, 3, Softwood nominal widths are 2, 3, 4, 6, 8, 10, and 12 inch. 4, 6, 8, 10, and 12 inch.

Standard available lengths are even Standard available lengths are even feet from 6 to 20. feet from 6 to 20.

Lumber with nominal thickness of 1 Lumber with nominal thickness of 1 inch is actually ¾ inches while 2 inch is actually ¾ inches while 2 inch lumber is actually 1½ inch inch lumber is actually 1½ inch thick.thick.


To find the actual width for nominal To find the actual width for nominal widths of 6 inches or less drop ½ widths of 6 inches or less drop ½ inch. inch.

For nominal widths of over 6 inches For nominal widths of over 6 inches drop ¾ inch to find the actual width.drop ¾ inch to find the actual width.

Board SizesBoard Sizes

Common boards and dimension Common boards and dimension lumber is bought and sold by the lumber is bought and sold by the board foot or per thousand feet.board foot or per thousand feet.

Board feet = thickness × width × Board feet = thickness × width × length divided by 12.length divided by 12.

Molding and trim boards are sold by Molding and trim boards are sold by the linear feet or running feet, rather the linear feet or running feet, rather than board feet. than board feet.


Linear feet: is simply length in feet Linear feet: is simply length in feet without regard to thickness or width.without regard to thickness or width.

Generally sold by the 4×8 sheet:Generally sold by the 4×8 sheet: Plywood, Plywood, Particle board, Particle board, Hard-board, Hard-board, Pegboard, and Pegboard, and Paneling are generally sold by the 4×8 sheet. Paneling are generally sold by the 4×8 sheet.


Thickness of these sheets vary Thickness of these sheets vary through a range of ¼, 3 / 8 ,½,5 / 8 , through a range of ¼, 3 / 8 ,½,5 / 8 , to ¾ inch. to ¾ inch.


All of these materials are priced All of these materials are priced either by the square foot or by the either by the square foot or by the sheet. sheet.

Other building materials, such as Other building materials, such as roofing and siding, are sold by “the roofing and siding, are sold by “the square”. square”. ““The square” actually means 100 The square” actually means 100

square feet of surface coverage.square feet of surface coverage.

Ordering LumberOrdering Lumber Do not order large quantities of Do not order large quantities of

lumber long in advance of the time it lumber long in advance of the time it will be needed. will be needed.

If delivered lumber must be stored for If delivered lumber must be stored for a period of time, care should be taken a period of time, care should be taken to avoid:to avoid: Warping,Warping, Staining, and Staining, and Moisture absorption problems.Moisture absorption problems.

Ordering LumberOrdering Lumber

Lumber should be neatly stacked Lumber should be neatly stacked using stickers or spacers every few using stickers or spacers every few rows to allow air circulation.rows to allow air circulation.

If stored outside:If stored outside: Keep the stack relatively level, Keep the stack relatively level, off the ground, and off the ground, and covered with moisture-resistant covered with moisture-resistant

covering like plastic.covering like plastic.

(Picture Courtesy, Interstate Publishers, Inc.)

ReviewReview How are lumber and wood products How are lumber and wood products

produced and processed?produced and processed? How is lumber graded and selected How is lumber graded and selected

of lumber?of lumber? How is lumber sized, bought, and How is lumber sized, bought, and

store?store?

Lesson A3–8: Selecting Lumber Selecting Lumber. Problem Area 3. Construction Systems.

Documents

process lumber

dressed lumber

lumber production

selection of lumber

type of lumber

rough lumber nominal

shop lumber factory

lower cost lumber