Any home modification that involves altering the existing chimney, such as a wood-burning stove installation, counts as "building work" and, therefore, falls under UK Building Regulations. You can read more about these regulations here.
The rules are long and technical. So, for that reason, we answer some common questions about wood stove installation in simple terms below.
Do I Need Planning Permission To Install A Wood Stove?
You do not necessarily need planning permission to install a wood stove. However, the law states that you need to let your local authority know about your intentions to install any heating appliance.
Planning permission only becomes relevant if you plan on making structural modifications to the building. If the property is listed, there may be restrictions on where you can place the chimney flue.
In general, you can only place flues in dedicated areas. Rules state that you're not allowed to put them on a side elevation facing the main road or the principal wall.
Can I Fit A Wood Stove Flue Liner Myself?
You can fit a wood stove flue liner yourself, so long as you have the necessary skills and competence to do the job correctly. In many cases, you do not require the assistance of professional installers.
Installing a standard flue liner to an existing flue is a simple DIY task that the average person can perform with relative ease. Installing flexible liners for wood stoves, though, is a little more complicated. You may require ladders and scaffolding to provide external access. The work is still straightforward from a technical perspective, but you may have to perform work at height.
Do I Need To Line My Existing Chimney For A Wood Stove?
Chimney liners are obligatory for anyone installing wood burning stoves in the UK. However, whether you need to install one depends on the age of your property.
Most homes built after 1964 have pre-installed concrete or clay liners which you shouldn't need to reline. Older homes are often bare brick. In this case, you only need to reline them if they are leaking. However, most experts recommend that you line them anyway as it facilitates cleaner burning of the fuel, reduced risk of fire, and general peace of mind.
Do I Need To Clean My Existing Chimney Before Installing A Wood Stove?
In general, you'll need to clean out your existing chimney before installing a wood stove and check for cracks. You can either hire a chimney sweep to brush it out for you or do it yourself if you have the equipment.
Before installing any new stove, check that smoke can escape the chimney and have no obstructions. Experts advise that you use a smoke pellet to check that smoke can rise through the entire stack.
What Type Of Hearth Do I Need For A Wood Stove?
The type of hearth you require for a wood stove depends on the size and the heat generated.
Regulations state that the area of the hearth should be at least 840mm by 840mm for free-standing wood stoves. There must also be a gap of 150 mm between the sides of the appliance and the rear edges of the hearth.
Wood stoves need to sit on a hearth made of non-combustible materials, such as concrete, slate, or marble. The thickness of the material should be greater than 100mm (or 125mm in the case of large stoves).
There are two further requirements:
- An air space of at least 50 mm between the bottom of the hearth surface and any combustible material beneath
- At least 250mm between the top surface and any flammable material beneath.
How Large Does My Wood Stove Flue Need To Be?
Most wood stoves come with an attachment that indicates the required size of the flue. Models typically come with a 125mm or 150mm outlet on either the top or rear of the appliance. All you need to do is source the corresponding enamel pipe to take waste gases from the stove to the chimney. When you reach the chimney, you need to convert a 125mm pipe into a 150mm one to comply with regulations.
Most flue pipe systems come with an adaptor kit, allowing you to adjust the flue to the required diameter.
DEFRA-approved stoves are an exception to this rule. In this case, you may not need to upgrade from 125mm to 150mm once the flue reaches the chimney.
How High Does My Flue Need To Go When It Exits The Roof?
The required height of the flue as it exists in the roof depends on the pitch of the roof and the position of the flue in relation to the ridge.
- Case 1: Within 600 mm of the ridge. If the flue exits within 600 mm of the ridge, it must allow gases to escape at least 600 mm above the height of the ridge.
- Case 2: Somewhere else on the roof. If the flue exits somewhere else on the roof, there must be at least 2300mm of horizontal clearance between the top of the flue and the ridge. The height of the flue, therefore, depends on the pitch of the roof. A Typical 30° pitch would result in a 1.8m high chimney above the tiles.
- Case 3: More than 2300mm from the ridge but near a roof light, dormer window or other openings. In this case, the flue must exhaust smoke at least 1000mm above the top of the dormer window opening.
- Case 4: Within 2300 mm of an adjoining building. The flue must be at least 600 mm above any part of the adjacent building.
Do I Need Extra Room Ventilation For A Wood Burner?
Usually, you do not require any additional room ventilation after installing a wood burner, provided the Kw output is not greater than 5Kw. The first 5Kw is free, so to speak, and then it's an additional 550mm² of ventilation per Kw, so, for example, a 7Kw stove would require an extra 1100mm² of ventilation (approx. the size of 2 x 50p pieces). A plastic vent could be installed through an external wall to achieve the additional ventilation required. Failure to comply with the additional ventilation into the room could cause the stove to burn inefficiently.
Please note that you must install a carbon monoxide detector. These are a good idea in general but are particularly helpful for providing an early warning if your flue backs up. Place 150mm below the ceiling, 300mm from a wall and between 1000mm and 3000mm from your wood stove.
Fitting A Wood Burner Into A New Passive Build Home
New-build passive houses are becoming more popular and are increasingly well-insulated and, therefore, more airtight. This is particularly relevant when installing a wood-burning stove or solid fuel stove into one of these houses. The main differences between a passive house and a 'normal' house are the insulation levels used during the build and additional airtight methods to prevent any heat loss. A well-insulated low energy home may only need around 1-3kW of heating which is good news for the overall cost of the user and the environment. The flue systems installed into these types of houses incorporate special components such as the Schiedel Protect Box and the Schiedel Ignis Protect system to prevent heat loss and offer a safe fire rating to meet current standards. The flue systems can rise vertically through the building or alternatively pass through an external wall as a common install would do; however, the special components are incorporated to maintain the "U" value of the house. A compliant stove must be used for passive houses offering a suitable air supply connection which can be taken from the external of the building. For safety reasons, a Honeywell CO alarm must be installed to meet HETAS requirements and ensure the safety of the occupants of the building should there be any leakage of carbon monoxide into the room.