The foundation is the very first component of a home to be built and produces the base for the remainder of a home's framing to finishing. There are 3 types of house foundations that are normally used in the U.S. and Canada today...Slab on grade, crawlspace, and full basement.
>>>> The First Type of House Foundations is the Slab Foundation...Also referred to as slab on grade. It is a structural concrete slab poured on the ground at grade height. There is no accessible crawl space with this type. Slab foundations are generally used in areas where the water table is high. [Water table is the depth in the ground where you find water].
>>>> The Second Type is The Crawlspace Foundation...A crawlspace is an accessible space usually 3 feet, normally between the ground and the bottom of the floor joist of a home. Crawlspaces are used in areas where there is a lot of clay content in the ground.
>>>> The Third Type is a Basement Foundation...A basement can be half sized or a full size living area between the concrete floor and the bottom of the floor joists. It typically has enough headroom so you can walk in it. Basement foundation construction is often used in areas of cold climates where the foundation footings need to be at least 4 feet below the frost level.
These 3 types of foundation are normally made from concrete, but some people used concrete blocks or insulated concrete forms. There are those who choose to use a wood foundation in areas where the ground is a lot drier.
Choosing the Type of Foundation you need to use…
Homeowners and contractors both have to make decisions about which type of foundation they want to use by determining cost, needs, and ground and atmospheric condition. If you live in an area that is subject to high water tables then it could not be conceivable to have full basement. If your property has shallow bedrock or lots of large boulders then it will probably cost more to dig the basement.
If you have an inclining lot it will be hard to use a slab on grade foundation. If you live in a colder climate you'll have to dig down at least 4 or more feet reach below the frost level. If you need to dig 4 feet deep then it may be a good idea to spend some extra money to dig out for a full basement. As well, it's simpler to set up and keep up mechanical systems in basements [as compared to a 3 foot crawlspace]. Your contractor can help you decide what type of foundation is required in your area.
Changing Your House Foundations…
If you’re going to be changing the type of foundation, you need to pay attention to where you'll be installing the furnace, hot-water tank, and stairway. If you need to have basement stairs installed, the stairs can typically be located under other stairways or you might have to replace a closet or add them in one of the nearby rooms. Another way to overcome this problem is to put the basement stairs in the mechanical room then relocate the mechanical items [furnace and water heater] in the basement.
Sometimes you can find some space near the laundry room, or a spot near the garage. Larger sized walk-in closets may also be cut down in size to provide the space for the basement stairs. Sometimes you can add basement stairs to your building plan without increasing the size of the plan. Even so, sometimes space could need to be increased to allow room for the basement stairs.
You should remember that it's the owner's full obligation to consult with local and state building agencies, local inspectors, and the designer of the house plan to make certain the home meets all required building codes.