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DD > Ch25 > Flashcards

Ch25 Flashcards

1
Q

Rough Carpentry and Finish Carpentry

- Define

A
  • Rough: structural framing, sheathing, blocking, etc. (usually hidden once construction is complete, except some exposed beams)
  • Finish: trims, bases, paneling, cabinetry, shelving (normally done on site, but can be pre-manufactured)
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2
Q

Lumber

- Pros and Cons

A
  • Pros: plentiful, low cost, easy to shape and assemble, good thermal insulating qualities, aesthetically pleasing
  • Cons: Lacks uniform appearance and strength compared to manufactured materials, susceptible to dimensions changes when moisture content changes
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3
Q

Characteristics of Lumber:
Types and Species:
-Hardwood and Softwood

A
  • Softwood comes from coniferous trees (like fir, spruce, pine), used for structural and rough carpentry because of greater availability and lower cost, as well as for finish carpentry and woodwork
  • Hardwood comes from deciduous trees (like oak, walnut, maple), used primarily for finish carpentry and architectural woodwork
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4
Q

Characteristics of Lumber:

Strength

A
  • Depends on direction of load relative to direction of wood grain
  • Strongest in compression parallel to grain, then tension parallel to grain, then compression perpendicular to grain
  • Weakest when horizontal shear force is induced
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5
Q

Characteristics of Lumber:
Defects
- Knots, checks, pitch pockets, shakes splits, wane

A
  • Knot: branch or limb embedded in tree, classified according to quality, size, and occurrence
  • Check: separation of wood fibers lengthwise through grain
  • Pitch Pocket: open area between rings that contains resin
  • Shake: lengthwise separation of the wood that usually occurs between or through rings
  • Split: separation between rings that extends completely through lumber, usually at ends
  • Wane: bark or absence of wood on the edge or corner of a piece of lumber
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6
Q

Characteristics of Lumber:
Warping
- Bows, crooks, cups

A
  • Warp: Any variation from true or plane surface, usually caused by natural shrinkage characteristics of wood and uneven drying
  • Bow: deviation parallel to length of lumber, in line with flat size
  • Crook: deviation parallel to flat side of the piece
  • Cup: Deviation along the width of the lumber
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7
Q

Characteristics of Lumber
Grading
- Why, how, primary concerns for structural or finish lumber

A
  • Lumber is categorized to allow selection of best piece for particular use
  • Grading done by visual inspection or machine
  • For structural lumber, primary concern is amount of stress that a grade of lumber of a specific species can carry
  • For finish lumber, primary concern is appearance and how it accepts finishes
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8
Q

Characteristics of Lumber
Grading
- Classifications of softwood lumber

A
  • Yard lumber: for structural purposes and rough framing

- Factory and shop lumber: for door frames, windows, and finish items

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9
Q

Characteristics of Lumber:
Yard Lumber
- Boards, Dimension, and Timber

A
  • Boards: Nominal dimensions up to 2” thick, 2” to 4” wide
  • Dimension: 2” to 5” thick, 4” or more wide
  • Timber: 5” thick or more, 5” wide or more
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10
Q

Characteristics of Lumber:
Yard Lumber
- Dimension lumber: subdivisions, examples

A
  • Light framing: 2” to 4” thick, 4” wide
  • Structural light framing: 2” to 4” thick, 2” to 4” wide
  • Structural joists and planks: 2” to 4” thick, 6” or more wide
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11
Q

Characteristics of Lumber:
Yard Lumber
- Timber: subdivisions, examples

A
  • Beams and stringers: 5” or more wide with a depth that is 2” or more greater than the width
  • Posts and timbers: 5” by 5” and larger, with a depth not more than 2” greater than the width
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12
Q

Characteristics of Lumber
Yard Lumber
- Common and select grades

A
  • Common: No. 1, 2, or 3 (1 is highest quality)

- Select: C or D select (C is highest quality

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13
Q

Characteristics of Lumber

Factory and Shop Lumber- Classification

A
  • Common: No 1 through 5, 1 being the best

- Select: B & Better, C Select, D Select

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14
Q

Characteristics of Lumber
Dimensioning
- Nominal to actual dimensions

A 
1" = 3/4" 
2" = 1-1/2" 
4" = 3-1/2" 
6" = 5-1/2"
8" = 7-1/4"
10" = 9-1/4"
12" = 11-1/4"
14" = 13-1/4"
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15
Q

Characteristics of Lumber
Dimensioning
- Board Feet

A
  • Measure of a quantity of lumber equal to a piece 12” wide by 12” long by 1” thick
  • Ex: Actual piece 3/4” thick, 11-1/4” wide, 2’-0” long contains 2 board feet
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16
Q

Moisture Content in Lumber

A
  • Weight of water in wood as a fraction of the weight of oven-dry wood
  • Affects amount of shrinkage, weight and strength, and withdrawal resistance of nails
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17
Q

Moisture Content in Lumber

-Fiber saturation point

A
  • When cell walls are completely saturated but no water exists in cell cavities
  • Averages about 30% moisture content in all woods
  • Above this point, wood is dimensionally stable (as it dries below this point, begins to shrink)
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18
Q

Moisture Content in Lumber

- Dry and Kiln Dry

A
  • Dry lumber has a moisture content that does not exceed 19%
  • Kiln dry lumber has a moisture content that cannot exceed 15%
  • Design values assume dry lumber, if moisture content exceeds 19%, must decrease allowable stresses
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19
Q

Moisture Content in Lumber

- Wood shrinkage

A
  • Shrinks most in direction perpendicular to grain, and very little parallel to grain (Especially important for wood members placed on top of each other)
  • Parallel to grain, shrinks most in direction of growth rings, and about half as much across the rings (Especially important consideration in cuts of wood)
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20
Q

Framing

A

Assembly of lumber and timber components to construct a building, usually limited to small to moderate sized buildings for wood framing

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21
Q

Light Frame Construction

A

Small, closely spaced members for walls and partitions, and nominal 2” thick members for floor and roof joists
- Beams may be built of 2x lumber, or heavy timber or steel

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22
Q

Platform framing (western framing)

A
  • Uses separate studs for each floor of the building, with top plates, floor joists, and floor framing of the second level being constructed before second floor walls are erected
  • Each floor can be completed and used for constructing next floor, and shorter studs cost less
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23
Q

Balloon framing

A
  • Continuous wall studs from foundation to 2nd floor ceiling
  • Vertical shrinkage is minimized because most of the construction is parallel to the direction of the grain, where shrinkage is least
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24
Q

Fire cut

A
  • Where wood joists are framed into masonry walls, diagonal cut at end of beam prevents masonry from being pushed up and out if the wood member collapses during fire
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25
Q

Framing wood joists into masonry walls

A
  • Joists must rest on metal hangers attached to wood ledger strips
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26
Q

Framing over a window opening

A
  • Usually a double 2x, size depends on the span
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27
Q

Framing a floor opening

A
  • Double header (when opening is 4’ or more) and double trimmer (trimmer runs parallel with the joists)
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28
Q

Plywood

A
  • Sheets of thin veneer glued together to form a rigid panel
  • Standard 4ft by 8ft sizes in thicknesses of 1/4”, 3/8”, 1/2”, 5/8”, and 3/4” (other sizes and thicknesses also available)
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29
Q

Plywood span rating

A
  • A measure of the strength and stiffness of the plywood parallel to the face grain
  • For most structural applications, including sheathing
  • Consists of two numbers (ex: 32/24) where the first number gives the max. spacing in inches for roof supports under average loading conditions, and the second gives max. spacing in inches for floor supports under average residential loading
  • These spacings are allowed if the face grain is perpendicular to the direction of the supports and if panels are continuous over three supports
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30
Q

Plywood veneer grades: N grade

A
  • Intended for a natural finish, made from all heartwood or all sapwood; free from defects, only available on special order
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31
Q

Plywood veneer grades: A grade

A
  • Smooth and paintable with few knots or other defects, best grade commonly available
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32
Q

Plywood veneer grades: B grade

A
  • Allows for plugged knotholes but has a smooth surface
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33
Q

Plywood veneer grades: C grade

A
  • Allows small knotholes and some splits
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34
Q

Plywood veneer grades: D grade

A
  • Allows larger knotholes
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35
Q

Sheathing

A
  • Thin panel material attached to framing to provide lateral support, increase rigidity, and provide a base for exterior finishes
  • Often plywood or particleboard
36
Q

Particleboard

A
  • Small wood particles, fibers, or chips mixed together in a binder and formed under pressure into a panel
  • Available in several sizes and thicknesses and in low-, medium-, or high-density
  • Generally preferred for backing and framing of finish carpentry and woodwork because it is less expensive and more dimensionally stable than plywood
37
Q

Oriented Strand Board (OSB)

A
  • Precision cut wood strands (max. 4” long and .0027” thick) arranged in layers at right angles and bonded with resin waterproof glue under heat and pressure
  • Primary strength is along orientation of chips on face layer, generally parallel to length of panel
  • More susceptible to delamination than plywood, but acceptable for sheathing with short-term weather exposure
38
Q

Medium Density Fiberboard (MDF)

A
  • Panel product made from wood particles reduced to fibers then combined with a resin and bonded under heat and pressure
  • Most dimensionally stable of the mat-formed panel products
  • Smooth, uniform, and dense surface is good for painting, thin overlay materials, veneers, and high-pressure decorative laminate
39
Q

Hardboard

A
  • Inter-felted fibers consolidated under heat and pressure to a specific density
  • Available sanded on one or both sides and either tempered or untempered (tempered has greater hardness, stiffness, and weight)
40
Q

Blocking

A
  • Wood framing installed between main structural members to provide extra rigidity or provide a base for nailing
41
Q

Bridging

A
  • Bracing between joists that prevents buckling
  • Solid wood blocking, 1 x 3 wood cross members, or metal cross briding
  • Intervals not exceeding 8 ft unless both top and bottom edges of joists are supported for entire length
42
Q

Firestops

A
  • Barriers installed in concealed spaces of combustible construction to prevent spread of fire caused by drafts
  • May include 2x wood members, gyp board, or mineral wool
    Generally used in concealed spaces between floors, between floor and ceiling or attic, between floors under stairs, and in vertical openings around vents, chimneys, and ducts
43
Q

Benefits of engineered wood products

A
  • Better use of natural resources
  • Improved product without typical wood defects
  • Increased strength for a given size compared with standard wood products
  • Consistent size and strength
44
Q

Plywood web joists

A
  • Plywood or OSB web fitted into grooves of solid wood or laminated chords
  • Same depths as standard solid wood joists, and deeper
  • Higher load carrying capacity as standard solid wood joists
  • Efficient use of wood
45
Q

Plywood web joists

- Advantages

A
  • Higher load carrying capacity as standard solid wood joists
  • Efficient use of wood and don’t require best quality wood
  • Minimal shrinkage
  • Ease of handling
  • Uniform size and shape
46
Q

Laminated veneer lumber

A
  • Thin veneers of lumber glued together to build up rigid, strong, dimensionally stable framing members that can be used like solid framing lumber
  • Used for headers, beams, studs
47
Q

Trusses

- Definition, spacing, spans

A
  • Factory made assemblies of relatively small wood members held together with toothed plate connectors
  • Common spacing is 24 in O.C.
  • Span up to 40 ft (floor trusses) to 70 feet (roof trusses)
48
Q

Structural Insulated Panels (SIPs)

A
  • Composite building unit of two outer skins bonded to inner core of rigid insulating material (usually 7/16” OSB facings with molded expanded polystyrene core)
  • Thicknesses from 4-1/2” to 12-1/4”
  • Panel sizes from 4 ft x 8 ft to 9 ft by 28 ft
  • Used for walls, floors, and roofs in residential and light commercial construction
49
Q

Structural Insulated Panels (SIPs)

- Advantages

A
  • Decreased construction time (1/3 less than stick-built)
  • Improved insulation value with no thermal bridges
  • Reduced air infiltration
  • Stronger than conventional stud and sheathing
  • Very flat walls for subsequent finishes
  • Dimensional stability
50
Q

Structural Insulated Panels (SIPs)

- Sustainability

A
  • Less wood than conventional framing
  • Renewable resources for facings
  • Improved thermal performance
  • Reduced construction waste
  • Low emissions
51
Q

Structural Insulated Panels (SIPs)

- Construction

A
  • Strength in compression, bending, shear, and uplift
  • Slip SIPs over wood plate attached to floor
  • Fasten panels together with wood splines at vertical joints
  • Vertical and horizontal chases for wiring, cut through with saw or hot wire for other pipes and equipment
52
Q

Structural Insulated Panels (SIPs)

- Common COncerns

A
  • Detailing a vapor barrier inside the panels
  • Seismic anchors
  • Termite shields
53
Q

Composite Decking

A
  • Small wood fibers (or wood flour) mixed with plastic and formed into planks (approx. 50/50 ratio)
  • Used for exterior decks and railings
54
Q

Composite Decking

- Advantages and disadvantages

A
  • Strong, durable, splinter-free, and typically made of recycled materials that may quality for LEED credit
  • Can be hot underfoot, depending on sun exposure, especially if dark in color
55
Q

Cross Laminated Timber (CLT)

A
  • Dimensional lumber layered at right angles to form thick structural panel
  • Custom sizes from 2 ft to 10 ft wide and up to 50 ft long
56
Q

Cross Laminated Timber (CLT)

- Structural qualities (loads, spans)

A
  • Resist axial, bending, and racking loads and provide diaphragm action for lateral loads
  • Spans up to 25 feet without intermediate support
57
Q

Cross Laminated Timber (CLT)

- Advantages

A
  • Manufactured under controlled conditions with pre-cut openings for reduced construction time on site
  • Made of small diameter timber, environmentally stable, no job site waste
58
Q

Heavy Timber Construction

- Building code requirements (UBC)

A
  • 8x8 nominal size minimum
  • 6x10 beams and girders supporting floors
  • Girders framed into masonry walls must be fire cut
  • Floor decking must be 3” nominal thickness with no concealed spaces below
  • Roof decking must be 2” nominal thickness
59
Q

Glu-Laminated Construction

A
  • Built up from individual pieces of lumber glued and finished under factory conditions
  • Used for beams, columns, purlins, and other structural components
  • Used where large wood members are required and simple sawn timber is not available to meet needs
  • Can be formed into arches, tapered forms, and pitched shapes
60
Q

Glulam Construction

- Dimensions

A
  • Usually in multiples of 1-1/2” deep, depending on number of laminations used
  • 3/4” pieces may be used for tight curves
  • Standard widths 3-1/8”, 5-1/8”, 6-3/4”, 8-3/4”, 10-3/4”, 12-1/2”
61
Q

Glulam Construction

- Advantages

A
  • Individual pieces can be selected to be free from defects and seasoned to proper moisture content
  • Manufactured under controlled conditions
  • Allowable stresses are higher than solid timber
62
Q

Glulam Construction

- Designations and grades

A
  • For structural purposes, designated by size and stress rating
  • Appearance grades range from industrial (worst) to architectural to premium (best)
63
Q

Wood Planking/Decking

A
  • Solid or laminated timber that spans beams
  • Nominal thicknesses of 2”, 3”, 4”, or 5”, with varying widths
  • Tongue and groove edging
  • Can span greater distances between beams (4 ft to 20 ft typ.)
64
Q

Wood Planking/Decking

- Advantages and disadvantages

A
  • Easy installation
  • Attractive appearance
  • Efficient use of material bc it serves as floor structure, finish floor, and finish ceiling
  • No place to conceal insulation, electrical conduit, or mechanical services
65
Q

Fasteners

- Nails

A
  • Most commonly used fastener for light frame construction

- Weakest of wood connectors

66
Q

Nails

- Types

A
  • Smallest to largest diameter: box nails, wire nails, common wire spikes
67
Q

Nails

- Schedules

A
  • Typical schedules found in building code

- Give minimum size, number, and penetration of nails for specific applications

68
Q

Fasteners

- Preferred orientation

A
  • Preferred orientation is to have fastener loaded laterally in the side of the grain, where holding power is greatest
  • Least desirable orientation is to have fastener parallel to grain
69
Q

Fasteners

- Screws

A
  • Threaded design offers better holding power and is easier to remove and replace than nails
70
Q

Screws

- Sizes

A
  • No. 0 (.060 in diameter) to No. 24 (.372 in diameter)

- Lengths from 1/4 in to 5 in

71
Q

Screws

- Construction

A
  • Slightly smaller holes must be drilled into wood to permit proper insertion of screw and prevent splitting of wood
72
Q

Lag screw

A
  • threaded with a pointed end, like a wood screw, but with a head like a bold
  • Inserted by drilling lead holes and screwing fastener into wood like a wrench
  • Washer is used between head and wood
73
Q

Bolts

A
  • Common for joints of moderate to heavy loading
  • Sizes from 1/4 in to 1 in
  • Used with a washer under head and nut of bolt to prevent crushing of wood and to distribute load
74
Q

Bolts

- Structural consideration

A
  • Design values and spacing is affected by thicknesses of main and side members, ratio of bolt length in main member to bolt diameter, and number of members jointed
75
Q

Metal Fasteners

A
  • Designed to make wood construction fast, easy, and structurally sound
  • Ex: joist hanger, post cap, saddle hanger, post base
76
Q

Split rings

A
  • Metal fastener for heavy timber construction
  • 2-1/2” or 4” diameter
  • Grooves are cut in each piece of wood member and split ring fits between, so half of ring is in each groove
  • Members are held together with a bolt concentric with the ring
  • Transfers larger loads than bolts or screws alone
77
Q

Shear plates

A
  • 2-5/8” or 5” diameter flat plates with flange extending from face to plate, inserted into pre-cut grooves in a piece of wood so the plate is flush with one surface
  • 3/4” or 7/8” bolt is placed through the plate to hold the members together
  • Transfer larger loads than bolts or screws alone
  • Esp. suited for constructions that must be disassembled
78
Q

Common sources of attack and damage to wood

A
  • Fungi (when moisture is present)
  • Insections (such as termites and marine borers)
  • Fire
79
Q

Pressure treatment

A
  • Most effective method of wood treatment
  • Preservative is forced deep into cell of wood
  • Three basic types: creosote, oil-born, and water-borne
80
Q

Creosote

A
  • Disstillate of coal tar
  • Effective protection against insects
  • Insoluble in water
  • Relatively easy to apply
  • Used mainly for railroad ties, marine timbers, not buildings
81
Q

Oil-borne preservatives

A
  • Often used for utility poles and cross arms, fresh water pilings, and bridge timbers
  • Brussed, dippped, or pressure treated application
  • Not used in buildings except some glulam beams supporting long spans in sports arenas, swimming pools, etc.
82
Q

Waterborne preservatives

A
  • Most common for residential, commercial, and industrial buildings
  • Clean, odorless, and nonstaining
  • Leave wood paintable
  • Protect against termites and decay
83
Q

Considerations in wood preservatives/treatment

A
  • Fasteners and connectors compatible with the chemical preservative should be specified
  • Cutting into treated wood
84
Q

Ideal configuration for wood stud wall construction

A
  • Structural sheathing applied to wood studs provides firm base for house wraps, air barriers, or water resistant barriers
  • Rigid insulation is applied over sheathing to protect WRB against win, to provide insulation as required for climate, and prevent thermal bridges (all in addition to insulation in stud cavity)
  • Vertical wood furring is fastened through to studs, and provides air gap and rain screen
  • Exterior cladding is applied over furring
  • Flashing at base of assembly
85
Q

WRB and Vapor retarder considerations

A
  • Correct permeance for climate and materials
  • Interior wall must be able to dry, to interior or exterior
  • Permeance and thickness of rigid insulation
86
Q

Advanced house framing

- Advantages

A
  • Reduce amount of lumber used and waste generated

- Improves energy efficiency by reducing thermal bridging and replacing lumber with insulation

87
Q

Advanced house framing

- Techniques (as allowed by building codes)

A
  • 24” OC spacing instead of 16” OC spacing for studs, joists, and rafters
  • Single top plates instead of double top plates
  • Covering openings with insulated headers
  • Single stud at window openings with header hangers to support header
  • Eliminate headers in non-bearing walls
  • Use ladder blocking instead of three-stud framing at the intersection of exterior wall with interior wall

DD (5 decks)

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