Have you ever wondered how your home is constructed?

So let's start with a question that goes to the very essence of building construction. How are buildings constructed? Well, to put it lightly, they can take a variety of different forms - such as masonry, concrete, timber, steel frame, and lastly, modern methods of construction.

If we were to focus on homes in particular, the vast majority fall within the category of traditional masonry. What is masonry though, you ask? Well, either brickwork, blockwork, or both, depending on the age of the building.

Many years ago, the internal and external walls of residential dwellings (homes) were constructed purely of clay brickwork - I'm talking about pre- 1930's here. The external walls of those buildings were formed of two separate skins (walls), constructed side by side. One of those brick skins would form the internal wall surface within the home, and the other brick skin would form the external wall surface exposed outside.

These two skins of masonry brickwork are offset from one another - built side by side - with a gap in the middle. This gap is called a cavity. Cavities are designed to keep any dampness away from the internal brick skin, since the external brick skin will get very wet from rain.

So you have two brick skins separated by way of a cavity, which originally were secured together using pieces of iron, to keep them structural stable, and to avoid one wall moving away from the other. These pieces of iron are called "cavity wall ties".

This entire assembly of two masonry brick skins, and the cavity within, form the external walls structure.

It's not always been the case there have been cavities, though - they were only introduced from the 19th century. Prior to that, external walls were formed of one single, much thicker, skin of masonry.

These external walls are constructed off concrete foundations - which are essentially a very large mass of concrete below the ground to provide stability and avoid subsidence, which is the terminology given to walls - and therefore buildings - sinking into the ground.

Since the 1930's, blockwork was introduced into building construction. Typically, these are situated to the "inner" leaf only - which to recap is the internal wall surface within home. Sometimes, though, the blockwork is formed to the "external" leaf only, finished with render, weatherboarding, or the like. Or, it can be present to both the internal and external skins.

As the masonry used in building construction advanced - so did cavity wall ties. Originally, wall ties were formed of iron, which would corrode very easily, and ultimately led to failure. However, nowadays, cavity wall ties are formed of stainless steel, which are much more resistant to corrosion and have a far longer life span.

There are, in addition, other building forms, such as timber framed construction, the inner leaf of which is formed of a timber frame typically finished with a brickwork external skin. There are also many other types of building forms too, such as concrete and steel frame, and modern methods of construction, although these are more commonly used for commercial buildings (more of those in a separate, future, article).

The external walls, irrespective of their construction, are, of course, finished with a roof, which, again, can take a multitude of different forms the most common of which is a timber framed structure finished with either natural or artificial (man-made) finishes, such as slate, clay tile or concrete tile.

The roof structure is supported by the external walls, which are in turn supported by the foundations, the latter of which are designed to dissipate the building load into the soil, the entire assembly of which forms the "building envelope".