Floor Framing

Grimsby Secondary School

Floor Framing Design

Factors affecting Design of Floor System: • Load (weight of material) • Size of members • Spacing of joists• Beams or bearing walls • Stress Design Criteria (How joists are

sized for proper span)• Deflection

Floor frame consists of

* Girders (Beams)

* Posts or columns

* Sill plates

* Joists

* Bridging

* Subflooring

Floor Framing

GIRDERS

• Larger principle beam made of steel or wood supported by posts/columns or piers which support the floor joists

• Can be recessed into foundation wall

Joists will set on top of girder• Can sit on top of foundation wall

Joist will hang off side with Joist Hangers

JOISTS SITTING ON GIRDER

RECESSED GIRDER

JOISTS HANGING FROM GIRDER

GIRDER COLUMN

Types of Girders (Beams)

•Solid lumber•Glue-laminated (GluLam)•Composite beams

•Parallam (PSL) •Micro-Lam (LVL) •Steel I-Beams

LVL - Laminate Veneer Lumber

PSL - Parallel Strand Lumber

Steel I-Beam Girder

Sills

• Often called Sill plates or Mudsills• Provide bearing for floor joists• Sill is attached with anchor bolts. • Spacing of bolts is determined by OBC Ontario Building Code

SILL PLACEMENT

SILL IS FLUSH WITH GIRDER

FLOOR JOISTS• Series of parallel support beams which support floor loads and which are supported by Girders, or bearing walls.

• Types• Solid Dimensional lumber (2x __) • Wood I-beams • Open Web Floor Truss • Steel Joists • Structural Insulated Panels (SIP)

DIMENSIONAL LUMBER

DIMENSIONAL LUMBER

CANTILEVERED JOISTS

WOOD I-BEAMS

• Structural, load-carrying I-joists used in residential and light commercial construction.• Composition

•The flange material for I-joists is typically dimension lumber or laminated veneer lumber (LVL)• The web is plywood or OSB.• The "I" configuration provides high bending strength and stiffness characteristics.

WOOD I-JOISTS

STEEL FLOOR JOISTS

Open Web Joists

FLOOR JOIST LAYOUT

FLOOR JOIST LAYOUT

FLOOR JOIST LAYOUT

RIM JOIST

Bridging Dimensional Lumber

• Joists have a tendency to sway and deflect over long spans• Bridging stiffens flooring• Types:

• Solid Horizontal bridging• Cross bridging

• Span greater than 10' have at least 1 row• Span greater than 14-16' have 2 rows of bridging, 5-8 feet apart

CROSS BRIDGING

SUBFLOORING

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