H2 Wood Framing Flashcards
True or false wood is the second most commonly used building material
True
How long does it take to grow a mature tree for suitable use as lumber
40 to 100 years
Which products have been made from the waste of lumber production or utilize smaller diameter logs?
Particle board, wafer board, dense fiberboard, laminated veneer lumber, glue laminated beams, parallel strand lumber beams, oriented strand board and plywood.
True or false, Wood ladders are used because they are poor conductors of electricity?
True
True or False, both oil and latex paint can be used on wood for interior or exterior purposes?
True
What is the relationship between wood and moisture?
All the properties of wood are affected by its MC, it can change in thickness and width due to it’s MC
How can you protect wood from decay?
Protected with chemicals or by keeping it dry and well ventilated. Below-grade wood must be treated with chemicals.
Eg paints, stains, alkaline copper quaternary and copper azole
How can wooden structures be made fire-resistant?
Using other materials over wood such as plaster or gypsumboard panels.
What are two main reasons for wood cracking?
Drying and nailing are two of many reasons wood may crack or split.
What can cause weakness in a board?
Loose knots
What kind of tree produces hardwood?
Deciduous
What kind of tree produces softwood?
Coniferous.
What is a crown?
It’s in this part of the tree that the food required for growth is manufactured. The crown may consist of the top 15% of the tree.
The more crown a tree has, the more it grows
What are roots?
The roots of the tree perform two functions, anchoring the tree in the soil and absorbing moisture and nutrients.
What is the Trunk of the tree?
The “stem” Provide structural support for the crown and transport food and moisture from the roots to the crown
Wood used for framing should have what MC?
15 percent to 19 percent
Wood used for finishing should have what MC?
8 to 11%
Where is water found within the wood?
Within the cell cavity(Free water) and in the fibres of the cell walls.(bound water)
When wood dries, when does shrinkage occur?
It does not take place until all the free water is gone from the cell cavities.
What is the density of wood?
Wood: 500 to 600 kg/M
What is the density of steel?
Steel: 8000 kg/M
What is the density of concrete?
Concrete 2400 kg/M
Why does using wood for window frames reduce condensation on the inside surfaces?
Wood is a better insulator than metal. Therefore wood is warmer, reducing the chance of warm moist air condensing on the frame.
How can wood be re-used? How do you prepare wood for reuse?
If wooden construction members are removed carefully.
Finish materials: Pull nails through the backside of materials to reduce damage to face materials.
How long does it take for wood to mature to a size that it can be harvested for lumber?
40 to 100 years
What happens when wood is exposed to atmospheric change?
Swelling or shrinkage occurs
Which hold its strength longer in fire situations, wood or steel?
Wood.
Which type of sawing produces the most “flat grain” lumber?
Plain Sawn
which type of sawing produces the most “edge grain” lumber?
Quarter sawn
What angle must the grain be to be considered edge grain?
Greater than 45 degrees
Describe “plain sawing”
Boards are cut through the full width of the log.
Which abbreviation is used for 1 x 10 re-sawn boards?
S1S2E
What does “S-GRN” stand for?
Surfaced green
Name the three main parts of a tree.
Roots»_space;> Trunk»_space;> Crown
This structure is an extremely thin region of living cells, which is responsible for the formation of the millions of new cells produced by a tree each year. The cells produced by this structure form other structures, which make up the bulk of the tree.
Cambium Layer
This region of the tree consists of light coloured, commercially valuable wood. Its function is to conduct sap upward from the roots to the crown of the tree.
Sapwood.
Consisting of dark-coloured, structurally weak material, this structure is located at the centre of the tree. First wood growth takes place around it.
Pith.
These long, narrow structures appear as fine lines on the surface of a cross section of a tree trunk or branch. Their purpose is to conduct food and moisture laterally across the trunk or branches.
Medullary Rays.
This corky material is composed entirely of dead cells. Its function is to protect the tree from pests, disease and damage.
Outer bark.
This part of the tree wood is darker than other structures. Composed of dead cells with natural tannins and resins, it’s more durable and less susceptible to decay than other wood structures. Its main function is to give the tree structural support.
Heartwood.
This region of the tree transports sugars from the leaves down to mix with water and nutrients from the roots.
Inner Bark.
These structures consist of concentric cirlces or rings, which are visible on a cross sectional cut of a new trunk or branch. They can be used to determine the age of a tree and eventually they form the wood grain pattern when a log is sawn into boards.
Annual growth rings.
True or False, Tropical woods tend to have an obscure grain, while most woods native to North America tend to have an obvious grain?
True
What is water in a cell wall called?
Bound water
At what stage of drying does wood begin to shrink?
Once all of the free water is gone from the cell cavity and bound water starts to leave cell walls
Where does the greatest shrinkage take place in a piece of wood?
Width and thickness
A cup is formed when what kind of grain board dries out?
Flat grain dries out, a cup is formed
Which is the heaviest speices of softwood?
Western larch.
Which is the lightest species of softwood?
Western Red Cedar
Which of the three species are considered to be the strongest of the softwoods?
Douglas Fir, Larch, Hemlock.
Which species of wood is considered to be free from resins?
Western Hemlock
Which species of wood is best suited for manufacturing ladders?
Sitka spruce
Name four species of wood that have very little or no taste or odour?
Spruce, some species of pine, balsam fir and alpine fir.
What species of wood is considered to be free from resins?
Western hemlock
Which species of wood is best suited for manufacturing ladders?
Sitka Spruce
Name four species of wood that have very little or no taste or odour?
Spruce, some species of pine, balsam fir and alpine fir
Which species of wood has a deep, warm brown colour?
Western red cedar
Before harvest logs are milled, what happens to them?
They are washed with high-pressure jets and then de-barked.
Which grain of wood will shrink more along it’s width, Edge Grain or Flat Grain?
Edge grain will resist wear better.
How can you tell visually that a board is Edge grain?
The grain pattern on the face of the board appears as relatively straight lines that are paralell to the edge of the board.
The angle formed by the annular growth rings and the face of the board is less than 45 degrees for which board?
Flat grain
Which produces more flat grain boards, Plain or Quarter Sawn?
Plain Sawn
Which produces more edge grain boards? Quarter or Plain sawn lumber?
Quarter
What % of Moisture does BC code allow for Framing Lumber?
19% max
Either Kiln dries or air dried.
What is the difference between surfaced green(s-grn) and surfaced-dry(s-dry) lumber?
S-dry lumber is surfaced AFTER being dried, less shrinkage.
S-grn lumber is surfaced BEFORE being dried, more shrinkage.
Which sides of rough lumber are surfaced?
They are machined on all 4 sides at once with a planer.
What does “S4S” mean?
Surfaced 4 sides (in the milling process)
What is a resawn board?
Example:
Plank is cut in half across their width with a bandsaw. This changes a S4S plank to two S1S2 boards.
How is lumber treated at the mill?
Due to tight packaging and moisture present, lumber is often surface treated at the mil to give cosmetic protection from mold and sap stains.
What is pressure-treated lumber?
Lumber treated with Alkaline Coper Quaternary(ACQ), to protect against fungi that cause rot and against wood-eating insects such as termites.
An S-GRN board of 2-4” has an actual dimension how much smaller?
7/16”
An S-GRN board of 6” has an actual dimension of how much less?
3/8
An S-Dry board of 8, 10 of 12 has an actual size how much less?
3/4”
An S-GRN board of 8, 10 or 12 has an actual size of how much?
1/2” less