H2 Flashcards
When a dry piece of wood is exposed to moisture, the cell walls absorb moisture until they become totally saturated and can hold no more. What is this called?
Fiber Saturation Point, or FSP.Once FSP is reached, additional moisture accumulates in the cell cavities as free water.FSP is reached at mc % of 25% to 30%
Which holds its strength longer in a fire situation would or steel
Wood
This part of Treewood is darker than other wood structures. Composed of dead cells with natural Tannins and resins it is more durable and less susceptible to decay then other wood structures. its main function is to give the tree structural support
Heart wood
What should be done when installing joist hangers for engineered floors
Double check to make sure the correct hardware as per the engineer
A cup is formed when a…. Grain board dries out
Flat green
Why is it easy to make a 4’ x 12 ‘ sheet of OSB but difficult to make it from plywood?
OSB is manufactured in very large sheets over 12 ‘ x 12 ‘ whereas logs for plywood are cut just over 8’
What grade plywood is used for sheathing if it’s sanded
Sheathing grade
What happens when wood is exposed to atmospheric change?
Swelling or shrinkage occurs
The outer bark of a tree consists of quirky layer material and can grow up to how thick
300mm
What is a powder post beetlew
The bore round holes 2 to 3 mm in diameter inside the wood. their tunnels are filled with sawdust and excrement. Sapwood with a high moisture content in shaded areas is especially susceptible to attack.
What is a western subterranean termite?
Feeds on wood and consequently can be very destructive to wooden structures. Live in wood in contact with the soil but will travel inside spec mud tube to feed on the wood above the soil. Mostly damaging basements at ground level.
What is shear strength in a nail?
The ability to resist lateral movement.Ex a ledger which supports a deck joist must be able to resist.EX Hangar nails with thick shank
What % of Moisture does BC code allow for Framing Lumber?
19% max Either Kiln dries or air dried.
An S-GRN board of 8, 10 or 12 has an actual size of how much?
1/2” less
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.
Compared to steel or concrete wood demonstrates as a
Good insulator
Two reasons to use a coated nail are:
1) Prevents corrosion 2) better holding power
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 first step when choosing framing hardware?
To determine the type of material being used.
What is the density of concrete
2400 kg/m³
What type of sign produces flat grain lumber?
Plane sawing
List four grades used with lumber classifies as light framing
Construction, standard, utility, economy
What is a check?
A separation of the wood, which normally occurs across or through the rings of annual growth. It’s usually the result of seasoning when there is uneven shrinkage.
What is pitch
The accumulation of resinous material. it usually collects when wood in the tree is damaged by wind or lightning
Before harvest logs are milled, what happens to them?
They are washed with high-pressure jets and then de-barked.
what size and spacing must be used to nail the double top plate to the top plate on a wall
3” nails at 24” o.c. or walls with studs sat 16” o.c. nails are placed at stud location to keep out of way for plumbing and wiring
What insects leaves piles of sawdust and makes wrestling sounds in walls
Carpenter ants
Name nine species Of wood that are readily available
Douglas fir, western larch, western, hemlock, Pacific Coast cypress, eastern larch, jack pine, lodgepole pine, sitka spruce and western red cedar
Where is machine stress-rated lumber used?
Critical members are engineered using wood-trusses.
What does the outer bark do
This quirky material is composed entirely of dead cells. It’s function is to protect the tree from pests, disease and damage
What happens in a diamonding defect?
The sides of timber are no longer square to each other.
What does “S-GRN” stand for?
Surfaced green
The colour is from a creamy white to a light pinkish tinge. There is a little difference between the hardwood and softwood, but a considerable difference between the Springwood and Summerwood. The wood is straight Grand and strong for for its weight to strength ratio. It’s ideal wood for ladders and Scaffolding after seasoning there is no taste or order. Light in weight, moderately stiff, moderately
Sitka sproue
What is brown rot
It attacks the cellulose material that makes up the walls of oneself, and eventually it reduces the affected wood to brittle, brownish material.
Diamonding
Is it change in the shape of a timber and is due to unequal shrinkage. The sides of the timber are no longer Square to each other
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
what is sawn lumber
Lumber that is cut from logs
Benefits of a box nail
They have a smaller diameter Shank but this weekend’s both their sheer and holding power are used when nailing into thin wood to prevent splitting
What are some disadvantages of using Wood
-It swells and shrinks when the moisture content in the atmosphere changes.-it is likely to rot or be invaded by insects-flammable-it is not uniform in composition ex: has knots and different speeds of growth affect its strength
What are actual dimensions of lumber vs nominal
.5 “ less for 2”-6”8,10,12 is 3/4 “ less
What is water in a cell wall called?
Bound water
What is Pacific Coast yellow cedar noted for
It’s resistance to acids and DEcay
Planks are cut in half across there with with a band saw this changes S4s plane to
S1S2E
Name four species of wood that have very little or no taste or odor
Spruce, some species of pine, balsam fir ,Alpine fur
What is compression wood
Abnormal wood that forms on the underside of leaning and crooked coniferous trees. it is characterized by hardness,brittleness, and a relatively lifeless appearance. It’s color is easily distinguished from that of normal wood. Lumber with this defect is not permitted if the defect can be readily seen, or if it rates potentially damaging in the stress grades, or if it is specifically listed as unacceptable
Flat grain or plains on boards are cut along the tangentical face and which way do they tend to cup
They tend to cup away from the center as they lose moisture
What is a pitch?
A pitch is the accumulation of resinous material. It usually collects when wood in the tree is damaged by wind or lighting.
What quality must framing hardware have when used with preservative treated lumber?
Corrosion resistant.
The sapwood region of softwood trees contains specialized cells which move sap through tiny openings called pits. what are they called?
Tracheids
How long does it take to grow a mature tree for suitable use as lumber
40 to 100 years
How you know Western subterranean termites are in your building
Western subterranean Termites live in wood in contact with the soil but will travel inside specially-constructed mud tubes to feed on wood above the soil. Most of the damage is confined to wood in basements and at ground levelThey are winged termites and are about 10 mm long and have black bodies and long pale wings
When a new layer of wood is added to the diameter of the tree every season, they are called?
Annual growth rings.
what kinds of finish and paint can you use on wood?
It holds very well if it is dry. it is easy to paint, stain and varnish.both oil base and latex based paint can be used on wood
How long does it take for wood to mature to a size that it can be harvested for lumber?
40 to 100 years
What is Rot fungus
It feeds on both the contents of the cells and the cell walls themselves and breaks large holes in the cell walls and holes cause the wood to deteriorate.
What is a pith shake?
A pith shake extends through the growth rings from or through the pith towards surface of a piece.Pith shake, heart shake, star shake or heart check.
What can cause weakness in a board?
Loose knots
When does wood shrink
When it dries
How can wooden structures be made fire-resistant?
Using other materials over wood such as plaster or gypsumboard panels.
What is a toeredo worm?
Destructive pest of submerged timber. Softwood can become riddled with tunnels within months of being in salt water
This layer is made up of extremely thin regions of living cells located between the inner bark and the sapwood. In this region the new cells making up the bulk of the tree or form cells are used by the tree to create new sapwood and new inner bark.
Cambium layer
What is the density, relative to water, for a hemlock log that sinks to the bottom of a lake?
Greater than 1.0 kg/M cubed
What is the coverage in the width for T/G plywood floor teething
47 1/2
Which hold its strength longer in fire situations, wood or steel?
Wood.
What does painted edge on OSB do?
Protect from moisture.
How long does it take for wood to mature to a size size that it can be harvested
From 40 to 100 years
List four grades used lumber classified as structural choice and planks
Select structural, number one, number two, number three
Which insect travels in specially constructed mud tunnels?
Western subterranean termite
Two basic types of sheathing panel
Wafer board, osb, plywood
What does Heartwood consist of
Dead cells formed by a series of chemical changes Heartwood color deep deepens as natural tannins and resin darker. These tannins and resins make Heartwood more durable and less common to decay
Describe cross banding
Is when layers of veneer and plywood are manufactured in right angles to one another
What is dry rot?
Dry rot infects trees after they are felled and can continue to thrive after the lumber-drying process. Dry rot often turns up after wood is put into service in poorly ventilated areas such as cavities beneath floors.
What does S-GRN stand for?
Surface Green
These long narrow structures appear as fine lines on the surface of the cross-section of a tree trunk or branch their purpose is to conduct food and moisture laterally across the trunk or branches
RAYS
What is the benefits of edge grain lumber
They do not suffer as much distortion when exposed to changes in moisture content
What is the abbreviation to know if Lumber has been surfaced after it’s been kiln-dried
S-DRY
What are three main causes of manufacturer defects in lumber
Improper seasoning techniques, improper handling, improper storage
Where is water found within the wood?
Within the cell cavity(Free water) and in the fibres of the cell walls.(bound water)
Similar to LVL, except instead of full sheets of veneer, strands of veneer are laid in parallel formation and glued together. Same use as LVL.
What is Parallel Strand lumber?
What is a split in a board
Separation of wood which happens when wood cells Tear apart
when must you use rigid foam insulation to fill wall cavities?
when you cant configure studs to allow for insulation to be put in after the roof is on.
What is dry rot
It survives the drying processIt occurs in wood surfaces that are in contact with damp wallsThe name dry rot arises from the condition which infected what is reduced. The wood breaks into dry brown cubes, which crumble to fine dust under finger pressure.
What is brown rot?
Brown rot attacks the cellulose that makes up the walls of the wood cell. Reduces wood to brittle, brownish material.Not persists after wood dies
What is a sound knot or live not
It is formed from a live branch. It starts out as a bud on the side of the treetrunk and as it develops successive layers of wood cover it. As a result both trunk and branch increasing girth at roughly the same rate as long as the branch remains alive it’s outer growth rings remain fused to the adjoining Trunk. and even after the tree is cut into planks the knot can be depended on to remain in place
What is sapwood and where is it located
It’s between hardwood and cambium layer.The main function of sapwood is to carry sap, water, nutrition from the roots to leaves and cones
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.
What is the density of Douglas fir
400 to 480kg/m3
An S-GRN board of 2-4” has an actual dimension how much smaller?
7/16”
In what location is a column Anchorage especially important
Locations were high winds can create extreme uplifting forces
What is the limit of spacing in framing members in balloon framing
24 inches
What is a structural strap used for?
Wall bracing
Wood used in construction must be uniform in size and grade, who regulates the sizes and grades?
NLGA - National Lumber Grade Authority
What are three common types of rot?
White Rot, Brown rot, and dry rot
What is machine gouge
A groove cut by the machine below the desired line
This structure of the tree is an extremely thin region of living cells which is responsible for the formation of 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
Does Brown Rot occur after the wood has been dried?
Most does not.
Why is balloon-frame construction only used in special situations
It is very time-consuming
How does decay occur? (rot)
All decay results from the invasion of a single class of plant called Fungi. Once MC% is less than 20, no further rot occurs but the wood will remain damaged.
What is sap stain fungus
It turns the wood blue but has no effect on the structural strength because it feeds on the contents of the wood cells without damaging the walls
List the four grades used with lumber classified as “structural joists and planks”
Select Structural, #1, #2 and #3.
In which application wood a knot be considered an asset
When it is in Knotty Pinewall paneling where knots lend a decorative quality to the final product
What is the difference between a loose knot and a tight knot
A loose knot is a dead not which has completely come loose and there is a hole in the board a tight knot is still the separate piece of dead branch still in the board.
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.
Glue laminated Timbers
Glulams are boards often 2x4 2x6 laid on flat and glued together to form a beam column they are produced in curved shapes, offering design flexibility and the BC building code includes plan tables and part 9 for glue laminated beams and lentils
What are four insects that damage wood
Carpenter ants western subterranean termitesPacific dampwood termitesPowder-post beetles
Which sides of rough lumber are surfaced?
They are machined on all 4 sides at once with a planer.
What 2 features do T&G have to help them resist water damage?
Painted edges, drainage holes along the tongue
Where does the greatest shrinkage take place in a piece of wood
In it’s width and thickness
Which type of frame construction is also known as Eastern frame construction
Balloon-frame construction
What angle must the grain be to be considered edge grain?
Greater than 45 degrees
In which type of framing construction are the studs 18 feet long and extend from the concrete at the bottom right to the top of the second floor walls
Balloon-fame construction
Which species of wood is considered to be free from resins
Western hemlock
What species of wood has a deep, warm brown color
Oh yeah Western red cedar
What is hardboard?
Denser than MDF, made from exploded wood fibers that are glued togetherUsed for clipboards, pegboards and drawer bottoms
What is Chip Marks
Shallow depressions or indentations on the surface of dressed lumber. They occur during dressing when shavings or chips become embedded in the surface
Water in the cell cavity is called bound water or free water?
Water in the cell cavity is called “Free water”
The building is made of wood and masonry what needs to happen
A space must be left at the top of the masonry veneer so that as the wood shrinks it will not be damaged since the masonry is stronger
Quite light and colour, and except for some Pines, have no to little odour or taste after being seasoned
Spruce, Pine, Balsam Fir, Alpine fir
What is the pith shake
It is also known as a heart-shake, star shake, or heart check it extends through the growth rings from or through the path towards the surface of the piece. it can be distinguished from the season check by the fact that the greatest width of the season check in the pith- centered piece is farthest from the pith
What is a ring shake or cup shake
The split which occurs between the growth rings and partially or wholly in circles the pith
What is Waferboard?
Waferboard looks similarused for floor, wall and roof sheathing, but not as strong as OSB 0-2
What is Sap-strain dungus?
Stap stain fungus causes wood to turn blue but has no effect on structural strength.Feeds on the contents of the wood cells without damaging.
In a stack of lumber, which boards are less likely to be warped?
Boards at the bottom of the stack, under weight of the other boards.
The region of the tree consists of light color commercially valuable wood. It’s function is to conduct sap upwards from the roof to the crown of the tree
Sapwood
Which species of wood is considered to be free from resins
Western hemlock
What kind of fasteners must be used when using acq treated lumber
Corrosion resistant
how are bottom or sole plates attached to joists or blocking?
nailed through the subfloor sheathing at 16” o.c. with 3.25 nails
What is the benefit of balloon framing
The lack of shrinkage and settling
In which type of framing construction are the second floor Joists resting on a ledger that is carved into the walls
Balloon-frame construction
Which grain of wood will shrink more along it’s width, Edge Grain or Flat Grain?
Edge grain will resist wear better.
When wood dries, shrinkage does not take place until when?
All the *FREE* water is gone from the cells.
Bright finished nails are used for what?
GC, including framing and sheathing. Rust in weather.
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.
IN what locations is column anchorage especially important?
Locatiosn where high winds can create extreme up-lifting forces.
Which insect leaves piles of sawdust and makes a rustling sound in walls?
Carpenter ants
What is a pitch streak?
A well-defined accumulation of pitch in the wood cells, in a more or less regular streak. It should not be confused with dark grain.
Which of the three species are considered to be the strongest of the softwoods?
Douglas Fir, Larch, Hemlock.
What is a cross laminated timber?
Engineered panel made similar to veneers in plywood. often an architectural feature
What is the density, relative to water for hemlock log that sits at the bottom of the lake
Greater than 1.0
What are the actual dimensions of a 2x8 that is surface green and what is the density of Western red cedar
Inch and 9/16 x 7 1/2Density of Western red cedar 310-340 kg M3
What causes chip marks
The occurred during dressing when shavings or chips become embedded in the surface are the material
How are seismic hold downs extended?
Threaded rods and coupling nuts
Define Douglas fir
Very stiff, very strong, very hard,. There’s a pronouns difference between the Heartwood which is orange red to red or sometimes yellowish
Where in Canada are Jackpine and Balsam fir Found
Eastern Canada
What happens to Wood when it’s exposed to atmospheric changes
It’s Wells or shrink because wood is diametrically unstable
What kind of nail would you use in marine construction, or when maximum corrosion resistance is required?
Stainless Steel Nails
What must be done if changes are made to the structure of a woodframe building
A complete review of design
Which type of defect occurs when particles of wood are broken below the line of cut?
Chipped grain
Nominal sizes are done when?
After rough cutting
What are the actual dimensions of a 2x8 that’s surfaced green?
1 9/16 x 7 1/2
What type of nail is best suited for exposure to the weather?
1) Stainless steel2) Hot-dipped galvanized
A screw length should be how much thicker than the subfloor when screwing in
Inch and a quarter
What kind of tree produces hardwood?
Deciduous
How do you prevent decay
Ensure that lumber has been dried to moisture content of 20% or less space ensure that wood placed in service is adequately ventilated treat wood with preservatives to prevent fungus attack
Laminated veneer lumber
Laminate veneer lumber looks like plywood beams, except all the piles have the grain running in the same direction. Made of multiple layers of thin veneers this lumber is very strong and stable and can span further than Sun timbers. Laminated veneer lumber can be used for rafters, headers, beams, joyce, rim boards, studs and columns
What is torn grain
An irregularity in the surface of a piece, where wood has been torn or broken out by surfacing.
What causes a board to warp
Incorrect seasoning or make her naturally due to great
Why have engineering building products been developed
They use waste that accompanies sawn lumber production and some of these products such as beams are not only stronger than solid lumber but are available in sizes wider and longer than the lengths cut from a single log
Water in the fibres of cell walls is called free water or bound water?
Bound water
What is a dead knot?
Forms after a branch dies. Happens in lower branches that have been deprived of light by dense foliage around them.
BOARD MEASURE - is
Board footage is calculated by multiplying the nominal thickness in inches(T) by the nominal width in inches (W) by the actual length in feet (L) anddividing by 12. The formula is: T x W x L = Board ft.12
Describe “Plain sawing”
When the boards are cut through the FULL width of the log.
Name four species of wood that have very little or no taste or odour?
Spruce, some species of pine, balsam fir and alpine fir.
And platform frame construction what is the standard platform framing stud length of the walls
92 1/4 inches. Which incorporates a single bottom [sole] plate and 2 top plates