All stove installations now come under building control. If you are in any doubt you should refer to the “Building Regulations of 2000 Approved Document J Combustion Appliances and Fuel Storage Systems 2002 Edition” or the building control department of your local council.
The 2002 edition of Approved Documnet J of The Building Regulations stipulates that any work that affects an existing chimney (ie fitting a new stove or line) or creating a new chimney now comes under building control.
All woodburning and multi-fuel stoves require a class 1 chimney. Existing chimneys can be used but they should be checked for air/gas tightness and correct diametre for the appliance to be used. It may be necessary to sweep the flue (which should always be done anyway before fitting a stove or lining a chimney).
Failing chimneys can be relined using a number of methods, one of the easiest methods is using a class 1 904/904 grade stainless steel liner. It is important that visual inspection must be made to ensure that the flue is not in close proximity to combustibles.
A permenant notice/date plate should be fixed at an appropriate poisition giving details of the location of the fireplace, they type and size of the flue and type of heating appliance used.
Click here to access Document J Building Regulations
Flue distances to combustible materials.
Any single skin flue pipe used must not come closer to combustibles than three times its diameter eg for a 6″ or 150mm pipe it needs to be a minimum of 18″ 450mm from a combustible material. This distance can be reduced to 60mm if a double skin insultated flue is used.
Hearth requirements
A stove must stand on a non-combustible hearth extending a minimum of 225mm in front and 150mm out from the stove at the sides. If the hearth is on a combustible floor it must be at least 250mm thick. Some stove manufacturers have models that have been designed and tested to have a hearth temperature not exceeding 100 degrees centigrade, in this case a 12 mm hearth can be used.
NB if you are using an appliance that is designed to run with the doors open then you must have at least 300mm in front of the stove.
If you are installing the hearth onto a non-combustible floor eg concrete, then the overall thickness can be 250mm for example if the non-combustible floor is made from 100mm of concrete then you have a slate hearth of 150 mm to make up the 250mm required.
If you are planning to install a stove into a room with no standard chimney then you must ensure that your hearth is a minimum of 840mm x 840mm. While this is a minimum if you have a large stove you must still follow the rules stated above eg 150mm each side and 225mm in front.
Handy tip
When laying a slate hearth never install the hearth as one piece. Always create a hearth out of at least 2 sections due to the heat produced by the stove. If you create the hearth out of a single piece it is possible that it can crack as there is movement likely.
Ventilation
Stoves use air from within the room for combustion. Any solid fuel stove which has an output higher than 5kWs requires a permanently open vent with a cross sectional area of at least 550mm2 for every kW above 5kW.
When installing a permanent air vent it must be non adjustable and ventilators should be installed to ensure the occupants are not provoked into blocking the air vents up to stop noise and draughts.
Air vents should not be installed into a fireplace recess except on the basis of specialist help. If you install a mesh or other type of guard to stop pests getting into the house then the mesh must be no smaller than 5mm.
You can position a permanent air vent anywhere in the room as long as it has direct ventilation to the outside.
Shropshire Building Supplies stock the “Blackhole” ventilator in various colours.
Flue Heights
When installing a twinwall double insulated chimney system you need to ensure that the chimney height is compliant with the building regulations.
The flue must clear the roof by the distances laid out below to ensure that you recieve a good draw on the chimney. Flue gases must be able to flow from the chimney freely in order not to cause any risks to property.
| Point where the flue passes through the weather surface. (Notes 1 and 2) | Clearances to flue outlet |
| At or within 600mm of the ridge. | At least 600mm above the ridge. |
| Elsewhere on a roof (whether pitched or flat) | At least 2300mm horizontally from the nearest point on the weather surface and either:
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| Below (on a pitched roof) or within 2300mm horizontally to an openable rooflight, dormer window or other opening. (Note 3) | At least 1000mm above the top of the opening. |
| Within 2300mm of an adjoining or adjacent building whether or not beyond the boundary. (Note 3) | At least 600mm above the adjacent building. |
Notes:
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When measuring the height of the chimney you MUST NOT measure at the top of the Rain cap you always measure from the area where the flue gases depart.