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List 2 benefits of alternating the grain while manufacturing plywood.
- 1. To minimize the amount of shrinkage or swelling
- 2. To add strength
How is a sheet of plywood designed to minimize dimensional movement?
The grain direction and thickness of the veneers is balanced across the thickness of the plywood
Area all the plies forming a sheet of hardwood plywood cut from hardwood trees?
NO, usually just the surface (face plie)
What are the benefits of using an engineered wood core in hardwood plywood construction?
- Usually costs less and is flatter
- BUT weighs more
How are softwood veneers typically cut for the production of plywood?
How are hardwood veneers typically cut for the production of plywood?
Rotary cut or plain sliced
How do the expansion characteristics of plywood along the face grain and across the face grain compare to the expansion characteristics of solid wood?
It is slightly greater along the grain but much less than solid wood
What are the benefits of using tongue and groove plywood for sub-floor sheathing?
Interlock to ensure effective transmission of load across joints; thereby, eliminating differential deflection between adjoining panel edges making the use of blocking or H-clips at longitudinal joints unnecessary.
List 2 finish flooring materials that can be applied directly over plywood.
- 1. Resilient flooring
- 2. Carpet
What must be completed before underlayment panels are installed?
Underlayment panels should not be installed until wood subfloor, concrete, plaster and lumber framing have dried to the approximate conditions that will exist in the structure during occupancy.
What type of plywood should be used as concrete forms to produce the highest quality concrete?
Overlays -- help to protect plywood from oil and water. They simplify form stripping and extend the service life of concrete forms.
Can plywood displaying an American grading stamp be used in Canada?
NO, because standards are not the same.
When cutting plywood, what is the maximum amount of circular saw blade should protrude beyond the material?
No more than 6mm (1/4"), and good face down
Does plywood bend more sharply perpendicular or parallel to the face grain?
Are all fiber board fibers laid out in the same direction during manufacturing?
NO - they are randomly oriented, creating equal expansion/contraction in all directions
What can be done to reduce the formaldehyde emissions from a composite panel?
Properly applied laminate/coatings can reduce emission levels by 95%.
list 3 benefits that composite panels have over solid wood
- 1. solid surface free from knots
- 2." "voids
- 3. " " grains
where should you never apply particle board underlayment?
over concrete or below grade
Why should laminate be applied to both sides of a composite panel?
To prevent an imbalance of moisture content and warping.
Should particle board underlayment be nailed starting from one edge or from the centre?
CENTRE - working outward. Nail each panel completely before starting the next.
What is the difference between the material used to produce fiberboard and the material used to produce particle board?
Fiberboard is typically manufactured from softwood broken down into wood fibers rather than particles (particleboard)
Can MDF be formed into different shapes?
YES -- available in lengths up to 20 feet.
How should MDF products be stored?
Stored inside and flat. Any significant contact with water will produce fiber rays, resulting in necessity of extra sanding to finish.
Describe the 3 steps of how OSB is manufactured.
- 1. Laying wood strands up to 150 mm long an 25 mm wide (mixed with an exterior grade adhesive resin.
- 2. Strands are aligned, mat-formed into panels
- 3. Compressed under heat.
List 2 benefits of using PSL beams.
- 1. Eliminating shrinking
- 2. Eliminate checking
What is the application of OSB panels?
Less expensive substitute for sheathing grades of plywood. A structural panel comprised of thin wafers of wood.
How do LVLs differ from plywood?
- LVLs: Veneer is laid up, with all grain parallel in predetermined patterns
- Plywood: Plies are cross-banded, the grain direction is alternated.
What components make up a decorative laminate sheet? (3)
- 1. Base of phenolic resin-impregnated Kraft paper
- 2. ...over which an overlay of printed paper or wood veneer is applied.
- 3. A thin sheet of melamine resin is laid overall.
What products are typically used for a base for laminates?
Laminates are commonly applied to core materials of plywood, particleboard and hardboard (the core must be defect-free)
What is the difference between polystyrene and polyurethane?
- Polystyrene: Thermal plastic foam that is available in board stock (rigid) or loose fill form.
- Polyurethane: Produced from the reaction of 2 ingredients (polyol & polyisocyanate), available in sheets or spray-in foam.
What must you remember NOT to do when applying vinyl siding?
Do NOT nail anything tight, otherwise the excessively expanding vinyl, plastic or metal may not be able to move lengthwise along the wall. Allowance for expansion and contraction approximately 6mm must be left at joints, panels, and corner posts.
List 4 areas in which flashing is required.
- 1. Valleys
- 2. Tops of doors and windows
- 3. Anything protruding through the roof surface (e.g. chimneys, vents, plumbing stacks)
- 4. Point where a wall intersects a roof (usually step-flashed)
List 4 advantages of metal stud framing over conventional solid wood framing.
- 1. Available in long splice free lengths
- 2. Eliminate warping and twisting
- 3. Made of flameproof material
- 4. Light and easy to handle
What are the most common types of resilient flooring? (4)
cork, vinyl,linoleum, and rubber.
When hand-sawing plywood sheets, where should the good face be faced?
Good face UP
When portable circular sawing plywood sheets, where should the good face be faced?
Good face DOWN
When table-sawing plywood sheets, where should the good face be faced?
Good face UP
What kind of plywood is difficult to glue?
Treated with wood preservatives and fire-retardant.
What should you NOT apply over particleboard?
What does PSL stand for?
Parallel Strand Lumber
What does LVL stand for?
Laminated Veneer Lumber
What must you do if using foam plastics on an interior of a building?
Cover with fire-rated gypsum board.
What kind of flashing can NOT be used with cedar shingles?
Copper flashing -- as the copper will permanently deteriorate
What is metal lath?
Plaster base made of metal, often as a diamond mesh