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1. Architecture Intro to Floor Joist and Sub flooring
2. What are Floor Joists? They provide support for the floor
Their sizes range from 2x6 to 2x12
Their spans (how far apart they are spaced) range from 12” to 24”
4. Their size depends on 4 concepts: Length of the space to be covered
Load to be supported
Grade of the wood (specie of wood)
Distance joists are spaced
Normally 16” O.C.
5. Different types of Loads on floors Live load– the weight from non stationary things…..people, beds, dressers, etc
Live load weight is 40 lbs. Square foot
Dead load—the weight from stationary items…..walls, chimneys, windows, etc
Dead load weight varies
6. What is a Load Bearing Wall? A wall that holds the weight of the house
Concrete Block wall
Cast concrete
Frame construction
7. Stairs and Chimneys They require more support, so double joists are used for the openings
Pg 197 fig. 11-10
8. Cross Bridging This can be used on plain wooden trusses to keep them straight over the years. (strengthen the joists)
Not normal today with special types of joists being made
10. Cantilevered Joists Produces an expanded floor space without the expanded foundation plan—garrison style house
Twice the overhang must be on the inside
Pg 201 fig. 11-18
12. Sub Flooring Usually ˝ “ 4’x8’ sheets
Plywood grain direction at right angels to the joists
Stronger
Staggered
Expansion joints
13. Sub Flooring Cont. If they are glued and nailed they create:
Stronger
Squeak free structures
14. Platform Framing Sill is the starting point
Supports joists
Normally a 2x6
Header joist all the way around
The joists flush against header sitting on sill
Then the sub floor is placed on top of joists