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FOUNDATIONS. Components. Footings Trench Formed Keyway Stepped Fireplace. Foundation Concrete support for floor framing & rest of the house. ACCURACY & QUALITY KEY! *Soil quality effects type of foundation used. Foundation: Carry Loads Distribute weight to soil evenly
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Components Footings Trench Formed Keyway Stepped Fireplace
FoundationConcrete support forfloor framing & rest of the house
ACCURACY & QUALITY KEY!*Soil quality effects type of foundation used Foundation: Carry Loads Distribute weight to soil evenly Footing spreads the weight Resists forces wind/earth (by anchoring down walls / eaves) Material: Concrete (works in compression) and Steel rebar (works in tension to resist min. earth movement)
Compression is a pushing force Tension is a pulling force
Requirements for footings • Rest on Undisturbed soil • Lie below the frost line (in colder climates) • Washington Country 12” • Multnomah County 18” • Check your local code • Slab on grade used in warmer climates • Footing width depends on soil type and # of stories
Footing Widths • Examples: • Soil bearing capacity 1000 psf +1 story= 18” Footing • Soil bearing capacity 3000 psf +1 story= 12” • Soil bearing capacity 1000 psf +3 story= 27” • Soil bearing capacity 3000 psf +3 story= 12”
More Footing Requirements • Horizontal Rebar per local code • Vertical Rebar per local code • Must project at least 2” beyond wall • A means of connection to wall • Keyway • Rebar
Slabs • Block Outs and penetrations designated by an X • Control Joints - control cracks (every 20’) • Expansion joint where vertical wall and slab meet allows for movement due to expansion and contraction.
Reinforcing Bar (Rebar) • Measured in 8ths • Example: #4 Rebar = 4/8 or ½” diameter #3 rebar = 3/8” diameter
3 Types of Residential Foundations • Crawl space • Basement (full or partial) • Slab on Grade Alternative FND. Pole / Pilings (when soil not good)
Crawl Space 18” minimum height from ground to bottom of floor joist
Abbreviations & Terms WWM = welded wire mesh WWF = welded wire fabric