Variations to these basic categories often arise from architectural innovation, using new materials or using established materials in different ways. While wood frame walls are most common across the US, concrete and steel, for instance, are often used in hurricane-prone regions.

Loadbearing and Non-Loadbearing Walls

The walls in any house can be divided into loadbearing or non-loadbearing. Loadbearing walls, as well as supporting their own weight, carry some of the load of other parts of the building, such as the roof and floors. Non-loadbearing walls support only their own weight, and are not structural components of the house. Always assume that all exterior walls are loadbearing (even though, in the majority of cases, it is only the internal leaf of a cavity wall that is loadbearing). It can be difficult to identify the other loadbearing walls in a house, but establishing whether a particular wall is loadbearing or not is vital when planning renovation work.

Basic Features of a House
Loadbearing walls transmit the weight of the roof and floors to the ground, while non-loadbearing walls act only as partitions. Foundations spread weight. Within these basic areas of construction there are many variations according to architectural preference and need.

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Types of Construction

Three main types of roof, four types of wall, and four types of foundation are shown here. They may be used in any combination so different foundations, walls, and roofs can appear together.

Types of Foundation

Foundations are the supportive structures on which all houses are built. The type used depends on a property's age, local codes, and the type of ground on which it stands.

Crawlspace
A crawlspace elevates the living space off of the ground, which is beneficial in termite-prone or damp regions. It allows a place and easy access for ductwork and pipes. It is less expensive than a full basement.

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Basement
Basements are usually built on a concrete slab, and a basement is actually a taller version of a slab. A footing is poured and foundation walls are constructed of poured concrete. Or a concrete block can be set on top.

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Slab
A concrete pad, reinforced with steel, covers the area on which the house sits. In some cases the edges of the slab, directly below the exterior walls, will be thicker than the rest of the slab. Modern slab foundations are well insulated.

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Pile and Girder
The walls are supported by a column of reinforced concrete, or steel, drilled into the ground. The depth and frequency of beams depend very much on the type of ground below the building, and the building size. Piles may also be required for internal loadbearing walls.

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