Presentation is loading. Please wait.
Published byFrederica Thomas Modified over 7 years ago
Competency: 206.00 Draw wall sections and details. Objective: 206.02 Apply concepts of wood sill and floor construction.
Lumber sizes Nominal sizes 2 x 4 2 x 6 2 x 8 2 x 10 2 x 12 Actual sizes 1 ½ x 3 ½ 1 ½ x 5 ½ 1 ½ x 7 ½ 1 ½ x 9 ¼ 1 ½ x 11 ¼ Common lengths 8’, 10’, 12’, 14’, 16’
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
Joists Provide support for floor Wood or steel
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
Joists Recommended live load (40psf) Distance between supports (clear span) Joists manufacturer’s charts
Joists Double joists must be provided under walls running parallel to the joist direction May be solid or built up of two joists
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
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
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
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
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
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
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
Girders (Beams) Glulam (cont’d) Disadvantages Weight Expense
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
Girders (Beams) PSL (Parallel Strand Lumber) Composed of veneers cut into strands Very strong Allows long spans
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”
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
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
Girders Types & 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
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 ¾” tongue and groove plywood
Subflooring Materials 1 x ___ board lumber, applied diagonally Plywood or OSB 4’x 8’ sheets speed the installation Structural particle board and composite board
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
© 2023 SlidePlayer.com Inc.
All rights reserved.