MATERIALS - WOOD Flashcards
WHAT WOOD DEFECT IS A KNOT
BRANCH OR LIMB
WHAT WOOD DEFECT IS A CHECK
Result Of Improper Seasoning. Checking is cracking that develops along the radius of a log. It rarely extends through the beam to the other side,
WHAT WOOD DEFECT IS A PITCH POCKET
OPEN AREA BETWEEN GROWTH RINGS THAT CONTAINS RESIN
WHAT WOOD DEFECT IS A SHAKE
LENGTHWISE SEPARATION OF WOOD USUALLY OCCURS THROUGH THE ANNUAL GROWTH RINGS heart shake, star shake, ring shake Shake is a timber defect. It occurs around the growth rings of a timber and is often found in older trees that grow in wet areas.
WHAT WOOD DEFECT IS A SPLIT
SIM TO CHECK EXCEPT SEPARATION EXTENDS COMPLETELY THROUGH PIECE OF LUMBER, USUALLY AT THE ENDS.
WHAT WOOD DEFECT IS A WANE
PRESENCE OF BARK OR ABSENCE OF WOOD ON THE EDGE OF CORNER OF PIECE OF LUMBER
WHAT ARE the FIVE SIZE GROUPS OF YARD LUMBER
- 2 to 4 inch thick, 2 to 4 inch wide
- 2 to 4 inch thick, 4 inch wide, category for 2 x 4
- 2 to 4 inch thick, 5 inch wide and wider
- more rectangular …Beams and stringers, 5 inches wide and wider, min of 2 inches more than width deep
- more square ..Post in Timbers, members 5” x 5” and larger with the depth max than 2 inches greater than the width
What Are Select Grades For Board Lumber
Select grades:
A - Does not exhibit knots, splits or visible defects.
B - A few small visible defects.
C - Small knots, but one side may be completely clear of defects.
D - May contain pin knots and other small blemishes.
actual dimension of 2x4?
1-1/2 x 3-1/2
actual dimension of 2x10?
1-1/2 x 9-1/4 (changes from 1/2” to 3/4” at 7” wide)
Sheathing
thin panel material attached to framing to provide lateral support, increased rigidity, provide base for applying exterior finishes.
Oriented strand board OSB
engineered panel product from cut wood strands maximum 4 inches long.
Plywood
manufactured from thin layers or “plies” of wood veneer that are glued together with adjacent layers having their wood grain rotated up to 90 degrees to one another.
Plywood graded in two ways
-First is by span rating 2 numbers: 32/24 first for roof second for floor, spanning perpendicular to the direction of supports and if panels are continuous over 3 supports. -Second by Quality of face veneer.
Particleboard
composed of small wood particles, fibers, or chips of various sizes mixed together in a binder informed under pressure into a panel
Hardboard
panel product composed of inter-felted fibers consolidated under heat and pressure. Available sanded on one or both sides either tempered untempered.
Medium density fiberboard MDF
from wood particles reduced to fibers. In a moderate pressure steam vessel then combined with the resin and bonded together under heat and pressure. The most dimensionally stable of the mat-formed panel products.
Plywood web joists
For the same depth they have a much higher load carrying capacity then wood joists, very efficient. Minimal shrinkage, ease of handling, uniformity of size and shape
Cross-laminated timber (clt)
layering dimension lumber is right angles to form structural panel. Like plywood CLT is formed from odd numbers of layers typically 3, 5 or 7. Panels are custom manufactured in range from 2 feet to 10 feet wide and up to 50 feet long. Very strong. Resist axial bending and wrecking loads and provide time from action for lateral loads spans up to 25 feet.
Parallel strand lumber ( PSL)
made by bonding long, narrow would strands together on the heat and pressure using waterproof adhesive. Proprietary product PARALLAM
Laminated veneer lumber (LVL)
thin glue laminated framing. Gluing thin veneers of lumber together to build up strong with your dimensionally stable framing member
Glued laminated construction / glulams
individual pieces or lumber glued together and finished on the factory conditions for uses beams, columns, purlins and other structural components. Heavy loads and long spans. In most cases 1-1/2” actual depth pieces are used so overall depth is some multiple of 1-1/2”,
Planking / decking
solid or laminated timber. Available in nominal thickness of 2, 3, 4, and 5 inches (actual sizes vary - manufactureD OF solid or laminated). tongue-and-groove edging, unlike sheeting, planking is intended to span greater distances between beams rather than between closely spaced joist. Common spans range from 4 feet to 20 feet.
-Oil-borne wood preservatives
-Oil-borne preservatives: Creosote is oil-based so can’t be painted, toxic, no longer used in new construction; pentachlorophenol is oil-based so can’t be painted, think of a telephone pole
4 Opaque wood finish types
Lacquer - Coding with high nitrocellulose content modified with resins and plasticizers dissolved in the volatile solvent.
Varnish - consisting of various types of business materials dissolved in one of several types of volatile liquids. Conservation varnish is produced with alkyd and urea formaldehyde resins. When high solids content is specified, the finish becomes opaque.
Polyurethane - synthetic finish that gives very hard, and durable finish. Difficult to repair or we finish, off of superior resistance to water, too many commercial and household chemicals, and to abrasion. Available in sheens from dull satin to full gloss.
Polyesters - another type of synthetic finish, gives hardest, most storable finish possible available only in full gloss sheen. Very difficult to repair and refinish, but very durable, 80% of hardness of glass.
wood Stains, 2 TYPES
Water-Based - Yield A Uniform Color But Raise The Grain
Solvent-Based - Dry Quickly, Do Not Raise The Grain, But Less Uniform In Color
What Is No. 1 Common Grade For Board Lumber - Softwood
No. 1 - Construction - Contains moderate number of tight knots. Paints well. - Siding, shelving, paneling
What Is No. 2 Common Grade For Board Lumber - Softwood
No. 2 - Standard - Contains larger and more numerous knots. Will accept paint fairly well. - Siding, shelving, paneling
What Is No. 3 Common Grade For Board Lumber - Softwood
No. 3 - Utility - Contains splits and knotholes. Will not accept paint well. - Sheathing, subflooring, crate construction
What Is No. 4 Common Grade For Board Lumber - Softwood
No. 4 -Economy -Contains numerous splits, knotholes and similar defects, which large areas of waste wood. Will not paint well. -Sheathing, subflooring, creation of forms for concrete work
What Is No. 5 Common Grade For Board Lumber - Softwood
No. 5 - Economy - Contains the largest amount of waste areas and courser defects. -Sheathing, subflooring, creation of forms for concrete work
Plywood graded by Quality of face veneer. N-grade
N-grade - natural finish made from all heart wood or all sapwood. Free from defects -
Plywood graded by Quality of face veneer. A-grade
A-grade - smooth and paintable, Best grade commonly available.
Plywood graded by Quality of face veneer. B-grade
B grade - allows for plugged knotholes, smooth surface
Plywood graded by Quality of face veneer. C-grade
C-grade - small knotholes, some splits
Plywood graded by Quality of face veneer. D-grade
D-grade - allows for large knotholes
Nominal dimensions from 1 to 5/4
1/4” less than nominal
Nominal dimensions 2, 3, 4, 5 and 6
actual dimensions 1⁄2” less than their nominal dimension
Nominal dimensions 8, 10, 12 and higher
3⁄4” less than their nominal dimension
Board-feet
is an approximation of the volume of lumber needed,
measured in nominal dimensions.
A 1x10 that is 8 feet long is 1x10x8’/12=6.7 board-feet.
-Water-borne wood preservatives
-Water-borne preservatives - PTI is less corrosive to metal fasteners; borate compounds (SBX and DOT) resist termites but not rot.
Bored holes
annot exceed 40% of stud depth
joist notches
boreholes
joist notches cannot exceed 1⁄6 of joist depth and may not be located in the middle third of the beam
boreholes annot exceed 40% of stud depth
dry lumber mc
dry lumber - cannot exceed 19%
kiln dried mc
kiln dried - moisture cannot exceed 15%
matching between adjacent Venere leaves - 3 ways
Book matching – most common - every other piece is turned over Jason please former symmetrical grain pattern
Slip matching - consecutive pieces side-by-side
Random matching - no particular sequence
matching veneers within a panel - 3 ways
Running match - simply alternates bookmatched Venere pieces regardless of the width how many must be used to complete a panel.
Balance match - Venere pieces a trimmed to equal widths
Central match - even number of veneer leaves of uniform width, so that there is some symmetry about a veneer joint in the center of the panel
matching panels within a room - 3 ways
Not matched / pre-manufactured - cheapest - normally 4 foot wide by eight or 10 feet long or assembled from Single flitch that yields from 6 to 12 panels. Field cut to fit around doors windows and other obstructions, resulting in loss of grain continuity
Sequence matching - use this panels of uniform width - manufactured for a specific job veneers arranged in sequence. Some panels must be trimmed to fit around doors /obstructions, moderate loss of grain continuity.
Blueprint matching - most expensive, manufactured precisely to fit the room and line up with every obstruction so that grain continuity is not interrupted
• Structural wood Panel Specification,
Exposure durability classification
Exterior: suitable for use as siding or other permanently exposed
applications
Exposure 1: have fully waterproof glue by don’t have veneers of as high a
quality as Exterior. Can be used for structural sheathing and subflooring
Exposure 2: suitable for panels that will be fully protected from weather and
will be subjected to a minimum of wetting during construction
About 95% of structural panel products are Exposure 1
S-DRY
S-DRY: Lumber with moisture content of 19% or less.
S-GRN:
S-GRN: Lumber with moisture content of 19% or more.
MC 15 , KD 15
MC (moisture content) 15 or KD (kiln dried) 15: Lumber with moisture content of 15% or less. However, this classifications does not effect structural performance.
The drying means, either kiln or air dried, does not effect the structural performance of the wood.
