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Lumber sizes. Nominal sizes2 x 42 x 62 x 82 x 102 x 12. Actual sizes1
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1. Competency: 206.00Draw wall sections and details. Objective: 206.02
Apply concepts of wood sill and floor construction.
2. Lumber sizes Nominal sizes
2 x 4
2 x 6
2 x 8
2 x 10
2 x 12 Actual sizes
1 ˝ x 3 ˝
1 ˝ x 5 ˝
1 ˝ x 7 ˝
1 ˝ x 9 Ľ
1 ˝ x 11 Ľ
Common lengths
8’, 10’, 12’, 14’, 16’
3. Sill Structurally graded according to knots (size, tightness, placement), wane, and straightness
Must be pressure-treated lumber
Used as a transition between masonry and standard lumber
Anchor bolts embedded into masonry are commonly used to tie the sill to the foundation
Nails can be shot into concrete with a low-caliber nail gun
4. Joists Provide support for floor
Wood or steel
5. Joists Size of wood joists depends upon
Species of lumber
Wood grade
Spacing
12”, 16”, or 24” O.C. spacing is most common
Works with the 48” module common to plywood and OSB
6. Joists Recommended live load (40psf)
Distance between supports (clear span)
Joists manufacturer’s charts
7. Joists Double joists must be provided under walls running parallel to the joist direction
May be solid or built up of two joists
May be solid or built up of two joists
8. Joists Bridging
May be used between joists
Transfers the floor loads to adjacent joists
Stiffens joists
Aligns joists vertically
May be diagonal wood members, metal or 1x3 wood cross bridging
May be solid blocking placed perpendicular between joists
9. Wood Floor Trusses May be used in place of solid lumber joists to provide support for the floor
Able to span longer distances than solid lumber joists
Reduce or eliminate the need for girders, piers, and columns
Allow for designing open spaces
Formed with top and bottom horizontal chords and diagonal webs constructed of standard size lumbers
10. Wood Floor Trusses Typically placed 24” O.C.
Open web construction
Reduces sound transmission through floors
Aids in ease of plumbing, electrical, and heating systems installation
Sizes are determined from manufacturers’ charts
11. Wooden I-Joists Similar to wood floor trusses
May be used in place of solid lumber joists to provide support for the floor
I-joists are able to span longer distances than solid lumber joists
Speed construction
Very straight
May come with circular knock-outs
12. Wooden I-Joists Formed with horizontal wooden (solid lumber or micro lam) top and bottom flanges, grooved to receive a solid plywood or OSB vertical web
13. Joist Header Used as rim joists with I-joist construction
Can be used with truss construction
Should be strapped to the sill in high wind areas
Double under exterior walls parallel to joist direction
14. Girders (Beams) Built-up
Formed with solid lumber nailed together
Built on the job
Glue laminated lumber (glulam)
Solid, 1x__ lumber, glued together under pressure
Graded according to appearance
Very strong
Able to span long distances
15. Girders (Beams) Glulam (cont’d)
Disadvantages
Weight
Expense
16. Girders (Beams) LVL (Laminated Veneer Lumber)
Glued veneers, similar to plywood
Advantages
High strength
Long spans
Disadvantages
Cost
Low moisture resistance causes delamination in high humidity
17. Girders (Beams) PSL (Parallel Strand Lumber)
Composed of veneers cut into strands
Very strong
Allows long spans
18. Girders (Beams) Steel
Beam Types
S – standard W – wide flange
S- beam W - beam
I-beams come in two standards
Wide flange
Standard wide flange
Beam supports greater weight
More stable than standard S-beam
“W 18 x 62” means “Wide flange beam, 18” tall, weighing 62 lbs/ft”
19. Girders (Beams) Steel (cont’d)
“W 18 x 62” means “Wide flange beam, 18” tall, weighing 62 lbs/ft”
Advantages
Strength
Ability to span long distances
Disadvantages
Weight
Difficulty in cutting on the job
20. Girders (Beams) Girder size
Determined by
Type of material used
Loads imposed
Clear span of the girder
Where loads exceed material limits, the girder span must be reduced by using piers, piles, columns, or posts
21. GirdersTypes & Components Drop girder
Flush girder
A ledger strip attached to the girder may support joists
Metal connectors may support joists or hangers attached to the girder
Where joists must tie to a steel girder, a wooden plate must first be bolted to the steel
22. Subflooring Provides a base for the underlayment and/or finish flooring material
Underlayment is material placed under finish floor coverings (i.e. as carpet, to provide a smooth, clean surface)
Underlayment can be combined with the subfloor into a single thickness
Single thickness underlayment/subfloor is generally constructed of ľ” tongue and groove plywood
23. Subflooring Materials
1 x ___ board lumber, applied diagonally
Plywood or OSB 4’x 8’ sheets speed the installation
Structural particle board and composite board
24. Crawl Space Considerations Access door is required
Recommended size 24” wide x 18” high
Large enough to allow for repair and/or replacement of under-house mechanical systems
Ventilation provided
Removes moisture from crawl space
8”x 16” vents are common