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Wood Flashcards

1
Q

how much % of world’s wood comes from North America?

A

1/3

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2
Q

t or f wood takes less energy to produce than that of steel, cement, copper and aluminum

A

true

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3
Q

what is the most economical choice for building materials

A

wood

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4
Q

what is wood technically?

A
  • dead or dying cells below the cambium layer

- made of small fibres that are long and narrow

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5
Q

what strength is wood strong in?

A

tension

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6
Q

what bonds the cells (cellulose) together in wood?

A

lignin

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7
Q

what % makes up wood?

A
  • 60% cellulose ; small long narrow cells
  • 28% lignin; glue that holds all together
  • 12% sugars and extracts
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8
Q

what are characteristics of hardwoods?

A
  • dicotelydons
  • oak, maples, birch ect
  • cells thicker, denser and stronger
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9
Q

what are characteristics of softwoods?

A
  • conifers/ evergreen
  • spruce pine fir and cedar
  • cells are thin, less dense and weaker
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10
Q

what is the pith of the tree

A
  • centre, where earliest growth occurs
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11
Q

what is the heartwood?

A

dead portion of the tree located towards the centre

-provides structural support, more resistant to rot

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12
Q

what is the sapwood?

A

-contains the living portion of the tree: sap

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13
Q

what is the cambium ?

A

growth area of the tree

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14
Q

what is the springwood ?

A

rapid growth, thin walled cells

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15
Q

what is the summerwood?

A

slow growth, thick walled cells

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16
Q

when does the growth year start/ stop of a tree?

A

-stops when tree drops leaves and goes dormant, starts when new leaf development

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17
Q

t or f, all trees have growth rings

A

-false; only occurs when climate limits growth part of the year

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18
Q

characteristics of cedar

A

-tannins, resists rot, easy to work with, food look, colour and aroma

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19
Q

uses of spruce ?

A
  • farming, must have preservatives for outdoor use

- good availability

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20
Q

uses of pine?

A
  • good availability

- needs preservatives for outdoor uses

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21
Q

what is the hardest softwood?

A

fir

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22
Q

characteristics of hemlock

A

-good rot resistance, poor availability, hard to work with

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23
Q

characteristics of fir?

A

-even grain, needs preservatives for outdoor use

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24
Q

redwood characteristics

A

-good for structure, rot resistant, poor availability= expensive

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25
characteristics of hardwoods?
-good for furniture, expensive, will rot and doesnt receive preservatives well
26
what are 4 natural destructive agents to wood?
- decay/ rot - fire - insects - UV rays
27
what 4 things need to be present for decay ?
- food supply - moisture - oxygen - warm temperatures
28
what is green wood?
- term for freshly cut or 'live' wood | - moisture content over 32%, could be as high as 100%
29
what is seasoning of wood?
- process of removing moisture from wood | - reduces moisture content to make stronger
30
what is the fibre saturation point
- as moisture content of wood is reduced from seasoning process, water removed from cell cavities and voids - any remaining moisture is contained within cells = fibre saturation point
31
what is the moisture content at the fibre saturation point?
25%- 32% | -point where cell shrinkage and reduction of wood column begins
32
what direction does wood shrink? by what % at the end of the seasoning process?
- width | - 2.6%
33
what varies as moisture content varies?
- strength - weight - shrinking - ability to resist and decay
34
when is wood considered 'seasoned wood'
-19%
35
describe natural method of seasoning wood?
- undercover/ out of direct sunlight and weather - open sides to env't - properly / neatly stacked off the ground with spaces b/ween layers --> air flow - takes min 1 year
36
what is kiln dried?
kiln dried 80- 100C for 24-48 hours
37
what is dressed lumber ?
-process of planing down the lumber to its finished dimension leaving it with smooth / dressed surfaces
38
when is the best time to dress wood?
- after the seasoning process so that most of the woods shrinking would already occurred - accurate dimension--> wood done shrinking
39
what would a piece of lumber be stamped with if it was dressed after seasoning?
KD- HT
40
what would a piece of lumber be called if it was dressed on green wood?
S-GRN
41
what is the most effective way to prevent rot and decay
add preservative --> Pressure treating
42
describe pressure treating process
- heat up wood to allow for better penetration than inject/ spray chemical on wood at high pressure
43
name 2 common chemicals used in pressure treatments?
- CA (copper azole) and ACQ (sodium borate)
44
which chemicals should you avoid pressure treating with?
- creosote (railroad ties) - pentachlorophenol (hudro poles) - both petroleum based
45
what is the difference between wood preservatives and coatings?
- coating provide protection but don't preserve
46
give 3 ex of wood coatings
stain, paint, water coating
47
what other benefits are there for coating wood?
1. reduce effects of UV 2. retard moisture fluctuations 3. provide increased resistance to abrasion
48
what is grading lumber
- gov't agencies that control grades of lumber | - measurement of amount of 'clear wood' in a piece
49
what is 'select wood'
- no large or loose knots and no less than 85% clear wood
50
name 4 common grades of lumber
1. select 2. structural 3. light framing 4. stud
51
who reinforces the grading of lumber?
- National Lumber Grades Authority (NLGA)
52
differences between western red cedar vs eastern white cedar
red: stronger psi - straight grain - higher shipping cost - high ability to hold fasteners White: -smaller, lots of knots - weaker - cheaper to ship - better posts
53
what are common sizes of lumber ?
1x2, 2x2, 2x4, 2x8, 2x10, 2x12 | 8, 10, 12, 14, and 16 lengths
54
what lengths do 1x 6 fence boards come in?
4, 5, 6, 8
55
describe how EcoVantage wood is produced?
no chemicals, wood treated with heat and steam - processed over 400F - eliminates sugars and starches
56
what are pros of ecovantage wood
- natural wood product - free toxins and chemicals - fully recyclable - bio- degradable - no resin, sugars, low moisture - 30 year warranty
57
key properties to EcoVantage wood
- permeability - warp. twist, expansion substantially reduced - hardness improved - strength reduced - density increased - biological durability improved
58
what is pervious concrete?
- 'No fines concrete' - concrete with interconnected voids to allow water to pass through - near 0 slump - course aggregate, cement, admixtures and water
59
what date was pervious concrete invented?
1852, became popular after WW2
60
what are pros of pervious concrete?
- reduced upfront infrastructure cost - reduce burden on again infrastructure - controls flooding and erosion - reduces glare - reduced ice pavement build up
61
how does pervious concrete improve water quality?
- removes 80% suspended solids from rainwater -contains hydrocarbon within system , then broken down over tiem by micro organisms
62
what is hydromedia technology ?
- 2nd generation High Performance Pervious concrete - uses sufficient paste to coat and bind the aggregate particles together to create a system of highly permeable, interconnected voids that drains quickly - doesn't require heavy compaction
63
name 3 types of hydromedia finishes
1. cost effective 2. coloured/ intergral 3. polished

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