Competency: 204.00

Draw Foundation Plans

Objective: 204.03

Explain footing and foundation wall construction.

Footings

Wider than foundation wall Purpose

Spread entire load of structure over wider area

Prevents uneven settlement

Determine Footing Sizes

Live loads include movable items People Wind Snow Furniture

Dead loads include all of the structure construction materials

Different soil types Support varying loads

Footings

Generally made of poured concrete Trench shapes footing Forms constructed for unstable soils Concrete withstands heavy loads Steel rebar adds support

Footing Design & Construction

Proper design & construction of utmost importance

Larger footings Aid in prevention of uneven settlement

Different loading conditions May cause uneven settlement

Footing Design & Construction

Effects of uneven settlement Doors & windows stick Cracks in finish materials Leaks in plumbing Structural element failure

Frost line

Depth to which the ground will freeze Depth varies with geographic location Local codes specify minimum footing depth

Footing placed below frost line Ground freezes & thaws

Expands and contracts Footing above frost line will be pushed upward

Causes cracks in foundation

Foundation Wall

Extends from footing upward to first floor

Commonly used materials Poured concrete Concrete block Brick Tile

Foundation WallPoured Concrete Composition

Cement Water Stone or other

aggregrate Use key to tie walls

to poured footing

Foundation WallsConcrete Block Most common CMU

Nominal size: 8”high x 8”thick x 16” long Actual size: 7-5/8” x 7-5/8” x 15-3/8” with 3/8”

mortar joint Thickness: 4”, 8”, 10”, 12” Styles

2 & 3 core stretchers Solids Lintels Corner Pilaster Jamb blocks

Foundation Walls

Thickness varies Construction factors Local codes Soil conditions

Shape is designed to handle horizontal earth movement Lateral earth shifting causes damage

Foundation Walls

Require damp proofing Heavy coats of tar or cement based

paint Thin coats of parging Drain tile

Perforated pipe surrounds structure Washed gravel holds back soil; allows

water to enter pipe Water is directed away from foundation

Foundation Walls

Polyethylene sheeting Thickness measured in millimeters (mils) 6 mil most common