|
|
|
Spread Footings
Spread footings provide a stable base or platform that prevents the house
from settling into the ground.
|
| The wide base (width) helps create a
large area to transfer the weight of the structure to the ground and prevent
the structure from sinking. The thickness of the footer provides the
footer with the strength needed to support the weight of the
structure. In modern construction, a footer is usually 16 to 24 inches wide
and 6 to 16 inches thick and made with poured concrete that is rated to withstand
2,000 to 5,000 pounds per square inch (psi) of compression pressure. The dimensions of the footer
may vary according to the soil
conditions under the structure, the weight (or load) placed on the footing
and construction style of the home. Other footing
materials used are wood, crushed stone, blocks (granite) and field stones. |
 |
| A continuous spread (or strip) footing is usually found around
the entire perimeter of the structure to support the weight (load) from the
exterior or foundation walls. In areas subject to seasonal frost, a footing must be
placed below the frost line to prevent frost heaving that may lift and damage the footing and structure. |
Pad Footing
A pad footing is like a spread footing but it is usually used to support a
single point of contact, such as under a pier or post. In modern
construction, a pad footing is usually a 2-foot by 2-foot square pad, 10 to
12 inches thick and is made with poured concrete that is rated to withstand
3,000 to 5,000 pounds per square inch (psi) of compression pressure.
|
Alternatives to Footings
Piles are wood, concrete or sometimes metal columns that are driven into
the ground, used to support the structure and prevent it from sinking
into the ground. Piles are either driven down until they rest on a
solid substrate, such as bedrock, or to a depth where the soil friction
against the side of the pile is sufficient to prevent any further downward
movement. A continuous grade beam is placed across the top of the piles,
forming
the platform on which the structure is constructed. Piles are used in areas where footings are not feasible or
desirable, such as with poor soil quality or a high water table near a
beach. In general, piles are more expensive to install than spread
footings.
|
 |
________________________________________________________________________
Structure Main Page
Foundation Main Page
Foundation Walls
Piers
Basements Crawlspaces
Return
to the Top of the Page
|
