Foundations Four Basic Types Footings Piers Pilings Slabs (*) Hello, my name is Kelly and in this presentation (*) I will be discussing the different types of foundations and why they are used.(*) Slabs

What is a foundation A system that supports and transfers to the ground a building’s load; may include footings, piers, pilings, and slabs. So what exactly is a foundation, and why is it used? (*) A foundation is a system that supports and transfers the load of a building to the ground. (*) There are different types of foundations that include; footings, piers, pilings and slabs. All types of foundations have a common purpose, that is to disperse the weight of the building about a larger surface area so as to limit the amount of settling into the ground. Or in other words to keep all or parts of the structure from sinking into the ground. (*)

What is a foundation cont. 1 sq. ft. 4 sq. ft. A simple way to think about how a foundation works is to imagine the old bed of nails trick. The picture on the left (*) would be similar to a bed of nails with very few nails (*). A large amount of weight would be concentrated, (*) or pushing down, onto the small surface area of the nails, (*) thus increasing the likelihood of being punctured. The picture on the right (*) would be more like a bed of nails with a very large quantity of nails. By increasing (*) the number of nails (or in this case the size of the footprint of the building) a person can rest (*) on a bed of nails without fear of being punctured. By increasing (*) the area in which the building rests, the average pound per square inch in lessoned reducing the risk that the building will settle, or sink into the ground. The size of the structure is the determining factor in the overall size of the footprint. The larger, or heavier the building, the larger the footprint needs to be to disperse the weight of the structure. (*) 1000 lbs./sq. ft. 250 lbs./sq. ft.

Choosing a Foundation Structure Size Soil Type Drainage Climate When choosing a foundation it is important to consider the following: (*) The size of the structure ~ Or more importantly how much the combined weight, or load of the structure will be. (*) The type of Soil ~ This can include particles that make up the soil including: Gravel, Sand, Silt, Clay and other Organic materials. Each type of soil has different characteristics on the effectiveness as a foundation base. (*) Drainage ~ orthe ability of the property to remove precipitation. (*) Climate ~ The average temperature of the construction site determines how deep the foundation must be dug. The colder the temperatures the deeper the foundation must go to be below the frost line, or the level at which the ground freezes. (*)

Footings Can be used with either: Crawlspace Basement Lowest member of a foundation system used to spread the loads of a structure across supporting soil. Foundation Wall Ground The first type of foundation that is commonly used in residential construction is called the (*) Footing. The footing, or footer, is the resting point for the foundation walls of the building.(*) The footing must be dug into the ground and poured to a certain depth depending on the location of the building. This depth is dependent upon the frost line, or the freezing level of the ground. Frost lines are different across the county based on the average temperatures of the area. The colder the average climate, the deeper the footing must be dug to ensure that the freezing and thawing of the ground does not shift the structure. By looking at the drawing below you can see that the footing itself is the widest part of the foundation wall so as to distribute the weight of the building about a larger area. The foundation wall rests on top of the footer and the heights of these walls can vary from structure to structure.(*) Footer Can be used with either: Crawlspace Basement

Piers Any various vertical supporting structures, such as a pillar, supporting an arch or roof or buttress. Ground The next type of foundation I will discussing is the Pier. (*) Piers, which would be described as a vertical supporting structure, such as a pillar, supporting an arch or roof or buttress. (*) Piers are generally used when it is important to raise the overall structure above a certain level. Such as near waterways, or in areas that have dramatic changes in the level of water similar to a flood zone. By raising the overall structure above a certain level, we are able to build in areas otherwise unsuitable for building.(*) Pier

Pilings A structure composed of piles; a heavy beam of timber or concrete, or steel, driven into the earth as a foundation or support for a structure. Ground The next type of Foundation would be the (*) piling. Pilings are used when it is not possible to dig all the way through to bedrock for a foundation surface. (*) In such a situation a piling is driven down into the earth to provide a solid foundation which can be used to build upon. The materials used may vary, but such items as wood, steel, concrete or any combination of those. Factors that dictate what materials and the sizes used depend on: the overall weight of the structure, the climate of the area in which the structure is built, as well as the type of soil the building is being built upon. (*) Piling

Slab A concrete floor system typically poured at ground level providing for the support of the structure. Slab Ground The last type of foundation that I will be discussing will be the (*) slab. Slabs foundations load the ground beneath the structure very little by dispersing the weight of the object about a large surface area. (*) These types of foundations are very rigid and solid. Slab foundations are primarily used in locations where freezing is less likely due to the fact that many of the components to the structure are buried within the slab foundation. This type of foundation allows the construction of structures in areas where it may not be economical to build other types of foundations. (*) Gravel