A constructional hearth is normally a concrete slab 125mm deep which runs beneath the fire out into the room. A decorative hearth lays upon the constructional hearth at or above floor level. Hearths must be constructed of non-combustible material to comply with building regulations.
A chimney works because the gases inside are hotter and therefore less dense than the air in the room. Because the air pressure inside the chimney is lower, air is drawn from the room and moved up the chimney along with any smoke and combustion gases. This is why it is important to have sufficient ventilation in the room to allow the chimney to ‘breathe’ properly.
Basket or grate
This is where the fire is lit. The basket or grate can be a stand-alone item within the recess or part of a larger insert. Inserts are cast iron and are often decorated using tiles.
Fireback
Within the recess, behind the basket or insert, there may be a fireback. A fireback is usually made of cast iron or refractory firebrick. The fireback lining serves to protect the masonry and to reflect heat into the room.
Lintels
The constructional lintel supports the brickwork above the fire and in some older houses can take the form of an iron arch bar or brick built arch. The throat-forming lintel forms an entry to the chimney, its function being to direct and lead the combustion gases into the flue.
Flue
The flue is the internal passage in a chimney through which the combustion gases pass to the atmosphere. For solid fuel a minimum height of 4½ metres (15 feet) is required to create a sufficient updraught.
Chimney
The chimney is the exterior brickwork in which the flue is contained.
Mantel
The decorative frame to an open fire. Wood, stone, marble, cast iron and fibrous plaster are among the materials that can be used.
Chimney Termination
This is the exit point for the products of combustion to discharge. In most situations an open chimney pot is sufficient for most types of fuels. For specialist advice on chimney pots, cowls and bird-guards contact us for a no obligation quote.