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These extra large flue liners are designed for building a traditional chimney above a large inglenook type fireplace opening.

A typical chimney construction would start with the liners being supported on a suitable lintel or gather if being used above an open fire.

The liners are jointed using a flue jointing mortar mix, 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 a standard insulating concrete mix.

A typical chimney construction would start with the liners being supported on the gather units that provide structural support to carry the chimney over the fireplace opening. Unfortunately there is no built in damper designed for use with these liners.
The liners are available in the following internal flue sizes, which can be used with the open fireplace dimensions shown depending on the overall chimney height and its location in relation to the roof and nearby structures.

300 x 300 Width 1000mm x Height 600mm 45,000 mm²
435 x 310 Width 1200mm x Height 750mm 67,425 mm²
545 x 310 Width 1400mm x Height 800mm 84,475 mm²


We can supply larger liners that are made to order.

We can help with ideas and answers for almost any situation, so please call us. Our friendly technical sales team are also HETAS registered, so you can be sure of a professional and enthusiastic service.

Some words of advice and other options

Whilst the thought of a roaring fire burning away in a large open fireplace can be appealing, there are some important points that need to be considered.

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, particularly as suitable permanently open air vents are required to provide sufficient air supply into the room.

To avoid having to have a large flue and lots of air supply, the following options are worth considering as they can be easier and far more efficient.

A few words about Building Regulations It is a legal requirement that all chimney installations comply with the Building Regulations, which for England and Wales is explained in the Approved Document J. These are minimum requirements aimed at making sure installations are safe. There are also Planning Permission requirements, which are explained on the Regulations page.