House Foundation
A foundation is the lowest part of the building structure. Foundations are generally divided into two categories: shallow foundations and deep foundations.

Shallow foundations, often called footings, are usually embedded about a metre or so into soil. One common type is the spread footing which consists of strips or pads of concrete (or other materials) which extend below the frost line and transfer the weight from walls and columns to the soil or bedrock.

A deep foundation is used to transfer the load of a structure down through the upper weak layer of topsoil to the stronger layer of subsoil below. There are different types of deep footings including impact driven piles, drilled shafts, caissons, helical piles, geo-piers and earth stabilized columns. The naming conventions for different types of footings vary between different engineers. Historically, piles were wood, later steel, reinforced concrete, and pre-tensioned concrete.

Foundation material
Concrete: In areas where the climate is mild, many homes have crawlspace foundations made of concrete blocks. Other areas will have poured concrete foundations where the concrete is poured into plywood forms reinforced with steel. Insulated concrete forms are covered with foam as insulation to make the home more energy efficient. According to the University of Illinois, concrete is a composite of cement, water and sand. It was used by the ancient Romans to build colossal structures such as the Colosseum and large arched domes.

Preservative Treated Wood: Preservative treated wood is a cost-effective solution in building foundations. The wood is pressure infused with preservative chemicals. It can be used for the construction of crawlspace stem walls and basements. Wood foundations are lighter, easier and faster to build, and do not require a poured concrete base to build on. According to Tool Base Services, more than 300,000 homes have been built in the United States with preservative treated wood foundations.

Foundation Dimension

Door Size
1st Floor Non ADA home: Bedroom, Bathroom, & Passage doors, and ADA accessible clothes closets: 36” [915mm] (32” [813mm] opening width required for wheelchair passage – between stops [or jambs if stop-less, or when hospital stops used] & includes door width when open). Linen closet 24” [610mm]. ADA accessible bypass closet minimum 66” [1676mm], else varies widely. Garage separation 36. Air handler 36 (when entire home is a return air pendulum).

Bedroom 32”. Bathroom 30, 32,(28 [712mm] cramped). Clothes closets: 32 master bed , 30,(28 cramped) secondary. Linen closet: 18~24” [457mm~610mm]. Secondary Passage 30, 32,(28 cramped). Garage separation 36, 32. Air handler 32. Bypass varies widely. 2nd Floor bedrooms (smaller home) 30”.

The standards for non ADA homes have existed since the 1930s. That doesn't mean everyone has followed them. ADA access is federally mandated, is more recent.
Window Size
Window size will vary depending on which room they are placed. Garage and basement windows, which are at the smallest end of the spectrum, are usually between 18 and 24 inches wide and 12 and 18 inches high. Bathroom windows are similarly small, typically 18 to 24 inches wide and 2 to 3 feet high. Bedroom widows fall between 2 and 4 feet wide and 3 and 5 feet tall. Dining rooms and living rooms usually have the most and the largest windows. The windows in these rooms are most commonly between 3 to 6 feet wide and 4 to 6 feet tall.
The Wall
Wall is made of 2x4 lumber and covered on the outside with an OSB sheathing. Using plywood or OSB as the sheathing gives the wall rigidity -- you may have seen diagonal pieces used at the corners of older homes (homes built before plywood was widely available). The plywood does the same thing, but it provides much more strength.

The 2x4s are placed on "16-inch centers," meaning that the center of one 2x4 is 16 inches away from the center of the next. In this wall, two things interrupt