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About Foundation Systems
Many would say that a good foundation is the single most important element of the home you are building. All foundations, particularly in the Northeast, require protection from shifting caused by cold weather conditions. There are several types of foundations. The foundation system you use will be determined by your preference, your budget and your local laws. Here is some basic information about the various choices.
A footer is a concrete slab that extends below ground frost level and supports the home or the walls of the foundation. It prevents the foundation from moving. Footers are used in all types of foundations.
A basement is a foundation that also creates living or storage space under the home. A basement is 8 to 10 feet high. Basements are made with a poured wall, block wall or a pre-cast wall. In some homes, you’d place utility elements like furnaces, water heaters and electric panels in basements. If you don’t construct a basement, those items will need to be placed somewhere in the house.
A crawl space a very popular type of foundation that is less expensive to build than a basement. Rather than excavating a hole for additional space under the home, a block wall, usually 4″ in height, is extended above grade. The wall is connected below ground to the footer. The look from the outside is similar to the look of a basement, without the extra room, storage, or expense.
A slab is another popular choice, usually called a “floating slab”. Depending upon soil conditions, professional slab plan may or may not require footers. Stability is maintained by good drainage. A compacted gravel base is the first layer, on top of which concrete is poured. The house is then placed on the slab. A slab may not be available for all types of homes.
Piers are the most cost-effective foundation, but are not suitable for all homes. Some jurisdictions do not allow pier foundations.
Piers involve drilling holes, usually 18 to 24 inches in girth below-grade, deeper than the frost line in your area; footers are poured below the frost line. These holes are then filled to ground level with cement. Then blocks and shims are placed on top of the pier supporting the home.
Which is the Best Foundation System For You?
Be sure that the foundation system you select is one that is acceptable to the local code enforcement officer and to construction and mortgage lenders. Before settling on a system that is intended to have a real property classification, it is always prudent to confer with area lenders about locally acceptable foundation systems.
A manufactured home must be installed according to the Manufacturer’s Installation Manual. Another foundation system called an “alternative foundation system” may be used if designed for the site by a New York State Licensed Professional Engineer or Architect, then submitted to the manufacturer and it’s Design Approval Primary Inspection Agency (DAPIA) for approval. Foundations for modular homes must be designed by a New York State licensed Professional Engineer or Architect. Generally, either a modular home or a manufactured home can be placed on any type of foundation.
There is no single “best” foundation system. When comparing foundation systems, consideration of each should include ventilation factors; methods of attachment; construction challenges; initial cost; real property classification; installation time; and resistance to wind, floods, gravity, frost and seismic loads. For example, basement foundation systems are far more expensive than other systems, are not recommended in flood-prone areas, and require more installation time. However, they can add significant amounts of usable space to a home; qualify as a real property foundation; and will resist wind, gravity and seismic loads when properly engineered.
Foundation systems are subject to the New York State building code. So, while the homes themselves may enjoy consistency of design and construction, foundation plans are subject to review by the local code enforcement official. Be sure to check with your sales professional and local zoning authorities to learn which foundation choices are available to you.