Wood burners in recently built properties (2008 onwards), new build properties, newly constructed extensions, and timber frame houses have requirements above and beyond stove installations in older and brick built properties.
The two mains areas of consideration are:
- Ventilation – stove and flue
- Distance to combustible materials
All stoves require a source of external air to ensure there is correct combustion within the stove. Building control regulations stipulate that for stoves with a rated output of 5kW or under, the natural draft ventilation available in older properties (windows, air bricks, door frames etc) will be sufficient. If the stove is over 5kW then additional, permanent ventilation is required.
New build properties require that additional permanent ventilation is present for all stoves, irrespective of size, as there is little natural draft ventilation available. Installing a stove in a new build, if not done correctly, can lead to the introduction of a draft via a permanent air vent and a lowering of the property’s energy efficiency.
Many good quality stoves come with optional external air kits allowing you to duct directly from the outside into the stove. This can be done in a couple of ways:
- by siting your stove near an outside wall and ducting from the rear of the stove through the wall; or
- by ducting under the floor. The under floor option often requires the ducting to be installed whilst the floor is being laid so would need to be known early in the building process.
Ventilation for the flue
Where a stove is retrospectively installed in a new build property careful consideration must be given to ventilation of the chimney. The most common retrospective installation is twin wall flue which can be run internally or externally.
Ventilation must be provided at the point the twin wall chimney exits the property (via a roof or wall) in order to prevent a build up of heat. Ventilation must also be provided between floors if the stove is run internally. In order to maintain the property’s air tightness and still provide ventilation points, a specialist twin wall chimney system is required.
Where a chimney forms part of the construction of the property a traditional brick or, more commonly, pumice system can be used. The stove will still need to be ventilated in the usual way but an external chimney breast will not compromise the air tightness of the property.
Chimney Options for New Builds:
Traditional brick built chimney to class one standard
A traditional chimney, constructed of bricks by a builder, they should be no less than 175mm in diameter but not so large as to impact the performance of a wood burning stove. They will also be lined with concrete or clay to help insulate the chimney and also lessen the chance of gases escaping through brickwork.
Pumice Block Chimney System
A Pumice system, such as Isokern or Anki, is a quicker and often more cost effective way of creating a chimney. Available in different sizes to suit the wood burning stove you intend to install, the block system is simple to install as the blocks are designed to be interlocking. These systems can be installed internally and hidden with fireboard, or externally and hidden with brickwork etc.
Twinwall Metal Flue
The simplest method for creating a chimney is to use a metal insulated flue system. This can be left on show or hidden behind boarding. Twinwall flue can be painted to match your stove or décor and only requires a clearance of 60mm to any combustible material.
If air tightness is an important factor twinwall system kits that form an air tight seal where it passes through a wall/roof are available.
Should you not wish to have a metal pipe on show above your home, then you can install a false chimney that hides the final section of twinwall flue inside. These chimneys come in a range of sizes and colours or with the option to have a brick façade.
2) Distance to combustible materials
Walls that are classified as combustible, including plasterboard finishes or with timber in their construction, are a determining factor in the final position of a new stove and its overall look.
It is not uncommon for a wood burning stove to require a distance of at least 500mm from its rear to any combustible materials. This can result in a stove installations that projects into the room in an unattractive and intrusive way.
Many of the manufacturers we deal with have gone to greats lengths to produce modified stoves that can be positioned closer to combustible materials. There are also a range of attractive products to shield the material from the stove and so bring it nearer. Below are some of the options and choices available to overcome this issue.
Heat shield panels on the stove
Modern stoves come with the option for heat shield panels or convection shields that reduce the required rear distance by half or better. A number of modified Charnwood and Jotul models are available. This is useful if you need to site your stove near a corner or have furniture near the stove.
Heat Shield panels on the wall
Instead of shielding the stove, you can instead shield the wall itself. Vlaze, produced on the Isle of Wight, offer a wall mounted Heat Shield Panel that can cut the required rear distance for a stove to just 100mm. Produced in the same factory as the signage for the London Underground, these enamelled panels are available in a choice of sizes and colours to suit most styles. Bespoke creations are also available should you wish to have a design tailored to your décor.
If you know where your stove is going to be situated whilst the construction process of your home is ongoing, then a high temperature fireboard can be used for the areas around the stove. This board does not count as a combustible material so maintaining a minimum air clearance of around 50mm is sufficient. This same board can also be used to create a false chimney breast in your new home, should you wish to have a more traditional looking fireplace.
The issue of combustible walls can be removed from the equation entirely by having your stove sit in the centre of the room. Stoves such as the Scan 83 have the option for a rotating plinth, allowing you to turn the stove to face any direction you desire.