Glencoe: Section 65 Flashcards
Select floor joist lumber carefully so that the floor will be,
flat and strong
Any joist with a slight edgewise bow should always be placed with the crown
on top
Crown:
the outermost curve of the bow.
How do you mark a joist with a crown:
an arrow pointing to the crown.
What happens to a crowned joist when the subfloor and loads are placed on it?
straightens out.
Be sure that knots in the joist are on its X side
compression (top) side. because they are less likely to cause failure in this location.
Why is a large knot on the tension side of the joist bad?
it can be pulled apart. A knot at the top will be compressed
Alternative layout method to marking joist location on the sill plate?
marking the top of the rim joist
The specific installation details for I-joists vary X. Always read the instructions for the specific I-joist you plan to use.
according to the product’s manufacturer
When installing an I-joist, check the X, do not check the Y
check the span table for that product, do not check the span tables for lumber joists.
The layout difference between I joists and lumber joists?
I-joists are usually not overlapped because they are available in long lengths
Do not assume the span listed for one line of engineered lumber products
will be the same as the span for another line.
Intermediate bearings:
load bearing wall must stack over X
X may be required at shear walls above or below.
wall below
Blocking panels
Temporary braces for joists (X maximum) at Y’ OC fastened at each joist with a Z nails minimum
1x4
6
2-8d (2 1/2”)
Bearing plate to be flush with
inside face of wall or beam
I joists are nearly always supported by
metal joist hangers.
The width of the hanger that supports the I-joist should match the width of
the I-joist
A backing block prevents
an I joist from moving within the joist hanger by improving its fit
Where an I-joist runs continuously over a support (a girder for example)
web stiffeners should be nailed to both sides of the web to improve the load-bearing ability of the i-joist. The stiffeners also provide addition bearing surface for lumber or I-joist blocking
Depending on the dimension of the I-joist, web stiffeners may be made of X”, Y”, or Z” thick plywood or OSB rated sheathing.
1/2”, 5/8” or 1”
I joists with usually wide flanges may even require a web stiffener made from nominal X” lumber.
2”
Why are stiffeners 1/8” shorter than the exposed potion of the the web?
so they do not force the upper flange out of position.
Installing lumber joists:
Step 1:
X, using 16d nails every Y” OC
Be sure that the outside face of the joists is in the same plane as the outside edge of the sill plate.
Toenail the rim joists to the sill plates
16”
Installing lumber joists:
Step 2:
X
Add extra joists or leave out the joists where large openings will be located.
Place the joists over the layout marks, laying them flat for now.
Installing lumber joists: Step 3: Tip the outermost joist up on edge and align one end with the end of a rim joist. X Y
Nail through the rim joist and into this joist with two 16d nails
Toenail this joist to the plate with 16d nails spaced 16” OC.
Installing lumber joists:
Step 4:
Proceeding from one end of the house to the other, X. This process is sometimes called Y.
Nail through the rim joist and into each floor joist with X . Toenail each joist to the sill plate with X
tip each joist on edge, crown up, and align it with the layout marks
rolling the joists
two 16d nails
three 8d nails.
Installing lumber joists:
Step 5:
toenail each joist to the girder with 8d nails
Installing lumber joists:
Step 6:
Face-nail overlapping joists to each other with at least three 10d nails.
Another method for installing web stiffeners is using X
10d clinched nails
Clinched nail:
a nail of any size or type whose point has been bent over with a hammer where it exits the wood. Which prevents the nail from pulling out
Where solid-wood blocking would be required on a solid-wood joist system, similar blocking may be required for
an I-joist floor. Short lengths of I-joist stock may be used instead of solid lumber.
Where I-joist blocks intersect I-joists,
a backing block or web-stiffener may be required.
A solid wood rim joist with an I joist floor is
A solid wood rim joist is not suitable for use with an I-joist floor
What type of rim board is used with an I-joist floor?
an engineered product such as LVL is used, called a Rim board
Rim board:
a rim board ties the ends of the I-joists together.
Dimensions of Rim board:
up to 24’ in length and 1 1/8” in thickness. Same depth as I-joists
Pros of rim board
does not shrink as much as lumber
To install a rimboard:
Toenail it to the sill plate with 8d common or box nails space 6” OC or as recommended by manufacturer.
When nailing through the rim board and into an I-joist,
make sure one common or box nail penetrates the center of each flange.
Notch:
a saw cut made in the end or edge of lumber.
Why does building code restrict notching
careless drilling or notching reduces strength of a joist
Notches may not be located
in the middle third of a joist span
The location and size of notches permitted in a solid wood floor joist are based partly on the
depth of the floor joist
Drilled holes must be at least X” away from the top and bottom of a joist
2”
Flanges must never
be cut drilled or notched.
I-joist contain what for utility access?
pre scored holes to be tapped out with a hammer.
If more holes or bigger holes are needed in an I-joist
consult the manufacturers literature.
When nailing through the rim joist or rim board and into the ends of a joist, always place
the bottom nail first. This holds the two pieces together so you can move your hand out of harm’s way as you fire the upper nail into place. Don’t forget to wear eye protection
Bridging:
a method of bracing between joists. It is done to distribute loads, prevent the joists from twisting and add stability and stiffness.
Two types of bridging:
solid bridging
cross bridging
Solid bridging:
solid bridging is made of solid lumber that is the same dimension as the joists. Offset or staggering the blocks allows them to be end nailed through into the joists perpendicular in between
Cross bridging:
(diagonal bridging) is more common because it is very effective and requires less material. Two bridges are used in between each joist in an X shape.
What type of lumber is used in cross bridging:
What other material can be used
1x3 or 2x2
metal-strap cross bridging
before installing bridging, snap a chalk line across the
tops of the joists as a guide.
When installing solid-wood cross bridging, leave
the bottom ends loose until the subfloor has been laid.
Why should you leave the bottom ends of solid-wood cross bridging loose until the subfloor has been laid
because the joists are then allowed to adjust themselves into the final position, then you complete the nailing
Bridging is not generally required by code unless the joist exceed
2x12 in depth.
Why would you bridge joists even though it is not required by code?
Because it is a cost effective and efficient way to stiffen floor.
If joist is over 8’ long and you want to install bridging, where do you install it?
at the center
If joist is over 16’ long and you want to install bridging, where do you install it?
install two rows of brides equally spaced on the joist span
Framing under bearing walls
joists should be what under each load bearing wall that is parallel to the joist
doubled under each load-bearing wall that is parallel to the joists.
Bearing wall
a wall that supports a load in addition to its own weight
if a wall will contain plumbing pipes or heating ducts, what can be added to the joists
blocking.
What dimensions are the blocking that fit under load bearing walls containing pipes or vents
the same size stock as the floor joists
blocking in doubled joists should be spaced no more than
4’ OC
It is often necessary to create large openings in the framing system to accommodate stairwells and chimneys. In these cases, the joists framing the opening
should be doubled and the interrupted joists must be supported by headers.
Header:
a horizontal member that carries loads from other members and directs them around an opening.
in a floor system, a header is supported by
a trimmer joist.
Trimmer joist:
used to form the sides of a large opening
tail joist is a floor joist
interrupted by a header.
The exact layout of headers is based on the
flooring loads as well as the size and shape of the opening.
When the opening in a floor system causes a header to span more than 4’
double lengths of joist stock are generally used.
When you have an opening in the floor system, in the cast of an I joist flooring a X header is often used
LVL header
The difficulty of framing a stairwell depends on
whether the opening runs parallel to the floor joists, as in stairwells parralel to the floor joists, or perpendicular to them, as in stairwell perpendicular to joists.
Which opening is easier to frame in a floor system
Opening parallel to floor joists, or perpendicular to floor joists
A parallel opening.
A rough opening in a floor system must be at least X” wide
37” wide
A finished opening in a floor system must be at least X” wide
36”
The framing for a bay window or similiar projection is often arranged so that the floor joists
extend beyond the foundation wall
A cantilever is
a supporting member that projects into space as is itself supported at only one end.
How is the weight carried in a cantilever
the joists carry the necessary loads and there is no need for separate foundation walls.
Cantilevered extensions should not exceed
2’
The joists forming each side of the bay, as well as the header should be X
How this is done depends on whether
doubled
The joists run parallel or perpendicular to the cantilevered section.
framing for a perpendicular stairwell may require
additional structural support
In floor openings, the subflooring is extended to the outer framing member and
sawed flush with that member.
Bathroom floor framing:
The weight and drainage requirements of plumbing fixtures involve
special framing.
Bathroom floor joists that support a tub or shower should be arranged so that
no cutting is necessary when connecting the drainpipe.
Framing under a bathtub:
Joists under the bathtub must be spaced X” OC
For a cast iron bathrub, X may be needed
12”
double joists
Blocking blocks stud cavity to
stop fire from spreading
Framing an opening:
Step 1:
Make sure the trimmer joists have been X. Double-check the Y of the opening against the plans.
doubled
width
Framing an opening:
Step 2:
Use a square to lay out the position of both X. The dimensions of the rough opening will be noted on the plans
headers
Framing an opening:
Step 3:
Attach X to the sides of the trimmer joists. Framing connectors are required by code if the header spans more than X’. Nail with 16d common nails or as specified by the connectors manufacturer.
framing connectors
6
Framing an opening:
Step 4:
X. Insert the X into the connectors. Nail into the header with 10d common nails or with joist hanger nails.
Cut header stock to fit snugly between the trimmers
stock
Framing an opening:
Step 5:
Install the X. Support the X on joist hangers nailed as in step 4. According to the building code, X over Y’ long must be supported by framing connectors or on Z” square ledger strips.
tail joists tail joists tail joists 12' 2"
When joists are parallel to the length of a tub, they are usually
doubled under its outer edge
What is the difference for the flooring layout of the first and second floor?
Instead of resting on a sill plate, the joists of the second floor rest on the double top plate of the first-story walls.
Finish framing material will be nailed to the underside of
second story floor joists
At the junction of a wall and ceiling, double joists provide
a nailing surface for the ceiling and interior wall finsih.
Another method of providing nailing at the ceiling line is to
install solid blocking, this may be required where a wall runs perpendicular to the floor joists
If X blocks are centered over a Y partition wall, they will provide a nailing surface of approximately 1” on each side of the wall.
2x6
2x4
Blocks should be firmly secured with X nails so that they will not be Y
16d common
hammered out of position when the drywall is installed.
The floor of most houses is built using some type of floor joist. However, there are other ways to build floor systems. For example, X is common in mild climates. It is a form of post-and-beam framing.
girder floor framing
In a girder floor system the girders are used like X
because
joists because they directly support a subfloor
Framing with girders:
Components of the floor:
————————————-
The girder method of floor framing is
sometimes used where
homes are built over a crawl space instead of a basement.
Framing with girders:
Components of the floor:
————————————-
In a girder method of floor framing, a system of X, instead of joists, supports the subfloor.
posts and girders
Framing with girders:
Components of the floor:
————————————-
In a girder method of floor framing,
Frequently, X girders are used and spaced X’ OC.
They are supported by 4X6 posts spaced
no more than X’ OC.
4X6
4’
5’
Framing with girders:
Components of the floor:
————————————-
Sometimes girders are
combined with X framing, as shown
in Girder Floor Framing.
box-sill
Framing with girders:
Components of the floor:
————————————-
Sometimes girders are combined with box-sill framing.
In other cases, the box sill is replaced by a X.
plate
Framing with girders:
Components of the floor:
————————————-
In a girder method of floor framing, a system of posts supports the subfloor.
X keep the wood from contacting the pier.
Asphalt roofing material or metal post anchors
Framing with girders:
Components of the floor:
————————————-
If square edge subflooring panels are used instead of
T&G (tongue-and-groove) panels, X
is required at unsupported edges.
blocking
Framing with girders:
Components of the floor:
Installation details:
————————————-
After the foundation walls are in place, locations for X are laid out and holes can be dug for the
X.
concrete piers
pier footings
Framing with girders:
Components of the floor:
Installation details:
————————————-
The piers should be set in a reasonably straight line. concrete piers height is not critical because
the posts will be cut to length as needed.
Framing with girders:
Components of the floor:
Installation details:
————————————-
After concrete piers have been set.
The sill is then cut to size and bolted in place
Framing with girders:
Components of the floor:
Installation details:
————————————-
The bearing posts must be cut to length
accurately to provide
a level floor.
Framing with girders:
Components of the floor:
Installation details:
————————————-
Bearing posts must be cut accurately.
A string is pulled tight from X. Then the distance is measured from the line to the top of each pier and recorded. This process is repeated for each line of piers until the height of each bearing post has been determined and recorded. Posts can be cut to
length with a circular saw or radial-arm saw
opposite sill plates over the piers
Framing with girders:
Components of the floor:
Installation details:
————————————-
After each post is attached to a pier then
Then the
girders are cut to length and toenailed to
the posts.
Framing with girders:
Components of the floor:
Installation details:
————————————-
If a low house profile is desired
or if the finished floor is to have a stepdown area, the
tops of the X in the step-down area are set flush with the Y.
A special metal hanger is used to
support the girder
girders
top of the sill
Framing with girders:
Components of the floor:
Installation details:
————————————-
Working space under the girders is
limited, so plumbing and heating lines are
X
roughed in before the subfloor is laid.
Framing with girders: Components of the floor: Installation details: ------------------------------------- After plumbing and heating lines have been roughed in
The subfloor is then cut and nailed in place.
Framing with girders:
Components of the floor:
Installation details:
————————————-
Describe the installation process:
Locations for concrete piers laid out Pier footings set in straight line Bearing posts are cut to length Bearing posts attached to pier Girders cut to length and toenailed to post
Framing with girders:
Components of the floor:
Laying the subfloor:
————————————-
The subfloor is usually of X” or thicker tongue-and-groove X. Some local building codes permit the use of X tongue-and-groove X subflooring over girder floor framing.
1 1/8”
plywood
2x6
plank
Framing with girders:
Components of the floor:
Laying the subfloor:
————————————-
The subflooring is cut even with the outside of the framing and nailed to the top of the X. 16d nails are used to X at the tongue and to X at a joint on all girders.
girders
toenail
face-nail
Framing with girders:
Components of the floor:
Laying the subfloor:
————————————-
After the subfloor has been cut and nailed in place, X
the surface is ready for the layout and erection of the walls.
Framing with girders: Components of the floor: ------------------------------------ Wall framing sits on top of X which sits on top of X which sits on top of X which sits on top of X
Subflooring
Rim joist
Sill plate
foundation wall
Estimating and planning: Floor framing: Number of Joists: ------------------------------------ Estimating methods are similar for both solid-lumber joists and I-joists.
Step 1:
To find the number of joists needed for a house, first X
Conventional joist spacing is X OC.
X the house length by those numbers to obtain the amount of joists needed.
divide the length of the floor by the joist spacing IN FEET.
16” or 1.33’
multiply by 0.75 or divide by 1.33’ (same thing)
Estimating and planning:
Floor framing:
Number of Joists:
————————————
Step 2:
add 1 joist for the end joist
Estimating and planning:
Floor framing:
Number of Joists:
————————————
Step 3:
Because I-joists extend from wall to wall but solid lumber usually doesn’t, double the floor joists.
Estimating and planning:
Floor framing:
Number of Joists:
————————————
Step 4:
Add one extra joist for each wall for which double joists are specified
Estimating and planning:
Floor framing:
Material Costs:
————————————
An accurate cost estimate of materials is made by multiplying the number of joists required by the cost per joist. However, a rough estimate can be made without knowing the exact number of pieces needed.
Step 1:
Find the area of floor by multiply the length times the width for each level
Estimating and planning:
Floor framing:
Material Costs:
————————————
Step 2:
Find the number of board feet required by referencing the table.
Estimating and planning:
Floor framing:
Material Costs:
————————————
Step 3:
Divide the total square foot of floor area by the graphs units (100 square feet increments).
For example 800sq / 100 = 8;
Estimating and planning:
Floor framing:
Material Costs:
————————————
Step 4:
Multiply the value in step 3 by the value retrieved in step 2.
Step 3: 800sq / 100 = 8; ------------ / ----------------- Step 2: 102 board feet ------------ = ----------------- 816 board feet.
Estimating and planning:
Floor framing:
Material Costs:
————————————
Step 5:
Use the chart to determine how many pounds of nails to purchase
Estimating and planning:
Floor framing:
Material Costs:
————————————
Step 6:
multiply the number of pounds of nails needed by the cost per pound.
Estimating and planning:
Floor framing:
Labor Costs:
————————————
To determine the labor cost for framing a
floor, you must know the joist size.
Step 1:
Get the total number of board feet in the joists system
In our example, the joists are 2” X 6”
X 10’. Refer to Table 15-3, which shows that
2” X 6” X 10’ boards contain 10 board feet.
For a building with 62 joists, as in our example, there would be a total of 620 board feet of joists:
Estimating and planning:
Floor framing:
Labor Costs:
————————————
Step 2:
Refer to Table 15-14 on page 420 to find
the labor rate. One worker in one hour can
frame 65 board feet of 2X6 joist material.
Estimating and planning:
Floor framing:
Labor Costs:
————————————
Step 3:
To find the total hours needed, divide the total board feet by the number of board
feet framed in one hour. The answer is
9.5 hours (620 / 65 = 9.5).
Estimating and planning:
Floor framing:
Labor Costs:
————————————
Step 4:
Multiply the number of hours by the
hourly rate.
Installing subflooring:
Are there any disadvantages to both gluing and nailing a subfloor?
————————————-
The layer of material directly over the floor joists is called X.
floor sheathing
What does floor sheathing form
It forms what is called the subfloor.
Floor Sheathing serves several important purposes:
It lends X to the building. It provides a Y for the finish floor.
bracing strength
solid base
What does subflooring act as?
a barrier to keep out cold and dampness. Keeps building warmer.
Subfloor sheathing provides a X for building the house
safe working surface.
Sheathing used to be made of X and nailed Y across floor joists
1x boards
diagonally.
Today solid lumber sheathing has been replaced by X
Why?
4’x8’ engineered panel products such as plywood and OSB.
because they are easier to install, do not squeak and create stiffer subfloor
A typical subfloor consists of
sheathing panels fastened directly to joists or girders.
Subflooring can be laid over supports spaced up to X” apart, depending on the design of the floor system and the thickness of the panel.
48”
If floor sheathing has a smooth surface,
finished flooring such as carpeting, resilient tile, and sheet flooring can be applied directly to it.
X is often used to install floor sheathing
common nails
When panels are glued and nailed,
fewer nails are required as compared to nailing only.
Glue-nailing:
when panels are both glued and nailed.
Benefit of glue-nailing:
results in a strong and stiff floor system
How is glue-nailing used to install floor sheathing.
A single bead of adhesive (type of construction mastic) is applied to the top of each joist with a caulking gun. Panels installed immediately after adhesive is applied in a small area.
What has become the most effecient way of nailing subfloor
pneumatic nailers
What if a builder prefers to drill screws in to floor sheathing
electric drills are made with special attachments that automatically feed screws into the tip of the drill with a coil.
In some cases, an extra layer of material is installed over the subfloor. This layer is called
underlayment
Underlayment:
Underlayment covers any minor construction damage to the subfloor and provides a smooth substrate for finish flooring such as sheet vinyl.
When should underlayment be installed?
Should not be installed until the finish flooring is ready for installation.
Why should the underlayment installation wait until the finish flooring is ready for installation.
This will prevent the underlayment from being damaged by other construction activiteis.
What is the underlayment made out of
plywood with a touch-sanded surface.
Touch-sanded surface:
the material is sanded at the mill just enough to ensure uniform thickness.
Step-by-step application:
Laying a panel Subfloor:
The general method for installing a subfloor is the same for plywood and OSB panels. However, you should always consult the manufacturers instructions.
Step 1:
Measure X” along the side of the foundation from the starting corner and mark this point. Repeat the process on the opposite side of the foundation. Snap chalk line between these points. This serves as an alignment guide for the sheathing
48”
Step-by-step application:
Laying a panel Subfloor:
Step 2:
Place a full panel even with X.
Align the edge with the chalk line. The grain of the plywood should run at Y to the joists. If the subfloor will be glue-nailed, spread a bead of construction adhesive on the joists just before installing each sheet.
one of the outside corners of the floor joists
right angles
Step-by-step application:
Laying a panel Subfloor:
Step 3:
Drive just enough nails to hold the panel in place
Step-by-step application:
Laying a panel Subfloor:
Step 4:
Place the next full panel in position at the end of the first panel. Be sure the joint is X, and leave about X” space between panels. Install it as in Step 2. Tip: Rather than measure this space, use a 10d box nail as a spacer. It is approximately 1/8” in diameter.
centered over the joist
1/8”
Step-by-step application:
Laying a panel Subfloor:
Step 5:
Begin second row at end of building.
Cut panel in half and nail it to joists.
Continue to lay full panels in the row.
Step-by-step application:
Laying a panel Subfloor:
Step 6:
Start the next (third) row with a full panel. This alternative method will stagger the joints used for support and provide the strongest floor. Continue to lay panels, driving just enough nails in each to hold it in position until all the panels are laid. Then snap chalk lines to indicate the location of floor joists. Complete the nailing as required.
What do the inner plies of underlayment-grade plywood do?
resist dents and punctures from heavy loads
To improve stiffness of the floor, what should be done to the face grain of the underlayment?
Placed perpendicular to the supports.
The edges of the underlayment should be offset at least X” from the edges of the subfloor panels.
2”
Blocking which supports subfloor panels should be cut from nominal X” lumber
2”
Sheathing with tongue and groove edge does not
need to be blocked between supports.
Tongue and Groove subfloor size and thickness
4’ x 8’
1 1/8”
Tongue and groove subflooring should be started with the tongue towards the
outside of the building
Wall framing basics:
The framing and sheathing for the first floor of a house create a flat and level platform on which
to build the walls
Why must work done at the stage where carpenters layout and erect the walls be done carefully?
because it will make the rest of the house more difficult to complete, for example cabinets will not fit well if walls are not plumb
After the walls are framed,
sheathing must be attached to them
Sheathing
rigid 4’x8’ or larger panels that are attached to the outside surface of the exterior wall framing.
What does sheathing do to the walls?
Adds great stiffness and strength to the walls.
Load-bearing wall:
a wall that supports weight from portions of the house above such as the roof is called a load bearing wall or simply a bearing wall
Exterior walls are nearly always
load bearing walls
Interior walls are also called
partition walls or partitions.
If an interior wall carries its own weight and wall covering weight then it is considered
not load bearing
When roof trusses span the entire length of the house, the exterior walls
support the weight of the roof and ceiling loads
When the roof is framed with ceiling joists and rafters instead of roof trusses, the interior walls
carry some of the weight of the ceiling load.
In most structures, ceiling joists cannot span the entire width of the house, what is then necessary to support that joist?
a load-bearing interior wall.
