Mantlepiece and grate styles have altered but the basic structural elements of a fireplace have not radically changed for hundreds of years. The early combination of a large stone or brick opening with a chimney built over it evolved from the obvious fact that smoke rises, rather than from a scientific understanding of how a well-designed flue system works. Consequently early wood and later coal-burning fires were very inefficient and it was not until a certain Benjamin Thompson (also known as Count Rumford) produced his thesis on the principles of fireplace design in 1799 that smaller grates and improvements in the internal shape of the openings were introduced.

A brick or stone enclosure forms the basis of the fireplace. Variously known as the fireplace opening or recess or builders opening, it may be set flush with the wall or built out into the room, forming a chimney breast. This chimney breast rises through the height of the house, emerging through the roof to form a chimney stack. At the top of the opening the gather and flue combine to carry the smoke up the chimney. If the chimney is shared by several fireplaces on different floors, it may contain more than one flue.

The masonry over the fireplace opening is supported by a lintel or a brick arch. Old inglenook fireplaces used massive oak beams, whereas a strong iron strap usually supports an early brick arch. Later fireplaces may have a straight arch supported by angle iron, and by the twentieth century cast concrete lintels were the norm.

A hearth, constructed from non-combustible materials such as stone or tile-faced concrete, projects out into the room to protect the floor from falling ashes. In most old houses the hearth was set flush with the floor, although sometimes a superimposed one was used to raise the level. The space within the fireplace opening, known as the back hearth, is usually level with the hearth itself. A dog grate for burning wood or coal can be placed on this back hearth. However, by the mid-nineteenth century the mass produced cast-iron register grate which filled the opening, had become the fashion.

To complete the assembly, a mantelpiece or mantel