Inglenook and Large Open Fire Chimneys
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Large open fireplaces or "Inglenook Fireplaces" as they are often called are a very popular focal point. If you want to have a large fireplace built, it is important for the chimney to be designed properly with a suitable gather and a flue size that is correctly calculated to match the fireplace area. |
Topstak provides a choice of the more popular systems to build a suitable chimney for a large open fireplace. The Isokern Manor Firechest The Manor firechest combined with the DM chimney block systems really does take the guesswork out of trying to build a large fireplace and chimney. The Manor firechests are the ideal way to build a large fireplace using the easy to handle pumice concrete components that are simply jointed together with the Isokern Lip glue. A flue damper is available with each firechest and is very useful for controlling the draught in the flue, and can be shut off to prevent heat loss up the flue when the fire is not in use. The firechests are designed to support the correctly sized DM quick build chimney block systems and are available in the following fireplace opening sizes.
All dimensions are for the bare opening and exclude the reduction when the required fire brick lining is added |
 The liners are available in the following range of internal flue sizes and are 245mm high with wall thickness of 60mm. 300 x 430 mm
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Marflex MLC concrete flue linersThese liners are made from a special mix of High Alumina cement and kiln burnt aggregate that has proven to provide excellent heat resistance and durability over many decades of use. The liners feature spigot and socket ends for secure location and jointing with fireproof mortar. A typical chimney construction would start with the liners being supported on a suitable gather providing structural support to carry the chimney above. The liners are jointed using fireproof mortar or fire cement jointing compound, then surrounded by a minimum thickness of 100mm brick, block or stone work. A minimum gap of 25mm must be kept between the outside of the liners and surrounding masonry, and backfilled with the standard insulating concrete mix. The larger diameters of Isokern pumice concrete flue liners are also suitable for use with large opening fireplaces. As mentioned before it is very important to ensure that the correct size of flue is provided to suit the size of fireplace opening. According to Approved Document J 2002 of the Building Regulations for England & Wales the flue size for a fireplace opening greater than 550 x 500mm for sue with solid fuel burning should be equal to a 15% of the total area of the fireplace opening. |
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Considerations and other optionsWhilst the thought of a roaring fire burning away in a large open fireplace can be appealing, there are some important considerations. A chimney works on the principle of creating a natural draught or draw when the hot flue gases rise up the flue. In a case of an open fire it is generally assumed that about 80% of the heat is drawn up the chimney, which is very inefficient and can also create uncomfortable draughts in the room. It is a Building Regulation requirement to ensure that suitable permanent air vents are provided into the room. If you want to have a large inglenook fireplace opening with an open fire that does not need a large flue or a large air vent, the Dovre 2000 is certainly worthy of consideration. As shown this fire is freestanding and there are a choice of canopies available. The doors can be folded to the side to enjoy the large fire opening and then shut when the fire is left unattended. This fire requires a 200mm (8 inch) diameter flue size, which is far more economical in comparison to using larger flue sizes. One can also have a free standing stove such as a Clearview 650. See our stoves page for more details |