Week 6 Wood floor systems

Question 1

Wood joist floors are an essential subsystem of wood light-frame construction. The dimension lumber used for joists is easily worked and can be quickly assembled on site with simple tools. True or false.

Answer 1

True

Question 2

Together with ______ or ____, the wood joists form a level working platform for construction.

Answer 2

Together with wood panel sheathing or subflooring, the wood joists form a level working platform for construction.

Question 3

Wood joists are spaced 12”, 16”, and 24” O.c. True or false?

Answer 3

True. It all depends on the magnitude of applied loads and spanning capability of the subflooring.

Question 4

The ceiling may be applied_____ to joists or be ____ to lower the ceiling area or conceal mechanical runs perpendicular to joists.

Answer 4

The ceiling may be applied directly to joists or be suspended to lower the ceiling area or conceal mechanical runs perpendicular to joists.

Question 5

In wood joists floor construction, End joists may be ______ to provide additional support for perimeter wall framing.

Answer 5

In wood joists floor construction, End joists may be doubled to provide additional support for perimeter wall framing.

Question 6

Lateral support is required for joist ends. True or false?

Answer 6

True. Rim joist/header

Question 7

Joists may be supported by ________ framing or ______beams, or a _______ of concrete

Answer 7

Joists may be supported by wood stud framing or steel beams, or a bearing wall of concrete

Question 8

Joist span is related to what 4 things?

Answer 8

1. Magnitude of applied loads
2. joist size and spacing
3. species and grade of lumber used
4. deflection allowable for the intended use

Question 9

What are 4 common span ranges for Wood joists?

Answer 9

Dimension Span
2x6 up to 10’
2x8 8’-12’
2x10 10’ to 14’
2x12 12’ to 18’

Question 10

If the overall construction depth is acceptable, deeper joists spaced further apart are more desirable for stiffness than shallow joists spaced more closely together. True or false?

Answer 10

True

Question 11

What is bridging?

Answer 11

Bridging consist of wood or metal crossbracing or full-depth blocking between each joist at 8”

Question 12

In platform framing:

1. a wood joist bears on the sill plate with a minimum distance of ?
2. In areas subject to insect infestation, install what?
3. End joists bear entirely on?
4. 1/2” anchor bolts space at_____” o.c.; minimum of ____ bolts per sill piece with one within ______” of each end
5. Pressure treated 2x__ or 2x___ sill plate is typical. Sill plate transfers____ and ____ loads to____.
6. Sill plates are laid over______ sill ____ to reduce_____

Answer 12

1. 1-1/2” toenail, three 8d
2. install a continuous sheet-metal shield
3. end joists bear entirely on sill plates
4. 1/2” anchor bolts at 6” o.c.; minimum of two bolts per sill piece w/one within 12” of each end.
5. Pressure treated 2x6 or 2x8 is typical.
6. Sill plates are laid over fibrous sill sealer to reduce air infiltration.

Question 13

What is subflooring?

Answer 13

Subflooring is the structural material that spans across floor joists, serves as a working platform during construction, and provide a base for the finish flooring.

Question 14

Subflooring typically consist of what?

Answer 14

It typically consists of plywood, although other nonveneer panel materials such as OSB, waferboard, and particle board can be used if manufactured according to approved standards

Question 15

What does the span rating mean and where is it located?

Answer 15

The span rating is part of the grade stamp found on the back of each panel. The first number indicates the maximum rafter spacing for roof sheathing and the second number indicates the maximum joist spacing for subflooring.

Question 16

Gluing combined subfloor-underlayment panels to the floor joists enables the panels to act together with the joists to form integral________.

Answer 16

Gluing combined subfloor-underlayment panels to the floor joists enables the panels to act together with the joists to form integral T-beam units.

Question 17

This application lessens ______ and ______, improves floor _______ and, in some cases, increases the allowable spans for the joists.

Answer 17

This application lessens floor creep and squeaking, improves floor stiffness and, in some cases, increases the allowable spans for the joists.

Question 18

Prefabricated, pre-engineered wood joists and trusses are increasingly used in the place of dimension lumber to frame floors because?

Answer 18

They are generally lighter and more dimensionally stable than sawn lumber, are manufactured in greater depths and lengths, and can span longer distances.

Question 19

How are I joists manufactured?

Answer 19

I joists are manufactured with sawn or laminated veneer lumber flanges along the top and bottom edges of a single plywood or osb web

Question 20

What are the advantages and disadvantages of wood I joists?

Answer 20

Adv:

1. Virtually no defects
2. Higher load capacities

Disavds

1. Not weather resistant
2. Unstable until sheathed

Question 21

What is the I joist spacing and what is the typical spacing?

Answer 21

12”, 16”, or 24” o.c.

24” spacing is most typical

Question 22

Solid sawn lumber

In the selection of a wood beam, what should be considered? (6)

Answer 22

1. Lumber species
2. structural grade
3. modulus of elasticity
4. allowable bending and shear stress values
5. the minimum deflection permitted for the intended use.
6. In addition, attention should be paid to the precise loading conditions and the types of connections used.

Question 23

What is a:

1. Built up beam
2. Box beam
3. Flitch Beam
4. Spaced Beam

Answer 23

1. A built beam - equal in strength to the sum of the strengths of the individual pieces if none of the laminations are spliced. Two members nailed w/10d @ 16” o.c.
2. Box beam - Made by gluing two or more plywood or OSW webs to sawn or LVL flanges
3. Flitch beam - Timbers set on edge and bolted side by side to steel plates or sections
4. Spaced Beam - Blocked and securely nailed at frequent intervals to enable individual member to act as an integral unit.

Question 24

What is glue-Laminated Timber and its advantages?

Answer 24

It is made by laminating stress-grade lumber with adhesive under controlled conditions, usually with the grain of all piles being parallel.
ADVS.
1. Generally higher allowable unit stresses
2. improved appearance,
3. availability of various section shapes.

Question 25

Glue-laminated lumber may be end joined with scarf or finger joints to any desired length, or edge-glued for greater width or depth. True or false?

Answer 25

True

Question 26

What is parallel strand lumber?

Answer 26

It is a structural lumber product made by bonding long, narrow strands together under heat and pressure using a waterproof adhesive. Parallel strand lumber is a proprietary product marketed as Parallam, used as beams and columns in post-and-beam construction and for beams, headers, and lintels in light frame construction

Question 27

What is laminated Veneer Lumber?

Answer 27

It is a structural lumber product made by bonding layers of wood veneers together under heat and pressure using a waterproof adhesive. Having the grain of all veneers run in the same longitudinal direction results in a product that is strong when edge loaded as a beam or face-loaded as a plank.

Question 28

Laminated veneer lumber is marketed under various brans such as Microlam, and used as headers and beams or as flanges for prefabricated wood I-joists.
True or False?

Answer 28

True