Guide to stove installation
From heat output to ventilation requirements, there’s lots to bear in mind when fitting your appliance. Rebecca Foster lays out what you need to know
Rebecca Foster explains the key considerations to safely incorporate this focal feature in your living space
hether you’re keen to install a contemporary wall-mounted unit or a traditional inset design, there’s no doubt that a stove’s warm glow will infuse your abode’s living space with cosy allure. Thanks to efficiency ratings often exceeding 80% or 90%, it’s no surprise that many people are opting to install modern woodburning or multi-fuel appliances rather than less effective open fires.
The basics
While electrically-powered versions offer a straightforward plug-in-and-go option, if you’re considering incorporating a gas, woodburning or multi-fuel model in your scheme, there’s a raft of factors to keep in mind. “Almost all the latter options will require a flue, so you will need to ensure that there’s a suitable channel available to accommodate this,” says Luke Deller, lead product support and design engineer at Stovax (there are a few flueless gas models available). A twin wall system is the most common arrangement. Air for combustion is sucked in through the outer pipe of the flue, while an inner conduit removes exhaust gases from the inside to the outside of the property, ensuring a healthy environment in your home.
“If you don’t have a chimney, in most cases a prefabricated setup can be fitted either internal or external to your dwelling,” says Luke. This functions in the same way that a chimney would, and allows you to enjoy the benefits of a gas, woodburning or multi-fuel appliance.
The earlier you factor the stove into your scheme, the better – preferably it should be incorporated at the initial design phase. That way, any structural work to the building, roof or floors can be carried out ahead of the installation. “All too often an appliance is purchased and sited without any thought for the flue,” says David Ebbs, technical and training support at Specflue. If the flue pipe protrudes above the ridge line of your house by more than 1m, you’ll need to attain formal planning consent.
Installation process
Before fitting a stove, you will need to arrange for a professional heating engineer to carry out a site survey. This assessment will identify the requirements for the appliance itself, the flue system, ventilation, hearth and other safety provisos laid out by Building Regulations.
The first step when installing the appliance is to set it into position. “The starting pipe is then added, as well as any locking bands and insulation. Next, a hole for the flue is formed between ceilings and floors, using firestop plates,” says Davinder Sangha, digital marketing manager at Schiedel. “The pipes are then connected using locking bands.” Where the conduit passes through the roof, supports are used to hold the structure in place. “Flashing and storm collars are added to avoid rain leakage, followed by a terminal with an optional mesh to minimise the chance of any birds coming through,” says Davinder.
If possible, a vertical flue without any bends works best. However, this may not fit with the design of your house. “The Building Regulations dictate the maximum number of bends, angles and total flue height,” says Specflue’s David.
If you’re renovating, the heating engineer will assess the state of your existing chimney – if you have one – as part of the initial survey. “The structure will need to be swept and the area assessed for any works required to make sure a stove installation is suitable,” says Richard West, head of fireside installation at Chesneys. Your engineer will be able to identify any damage, blockages or leaking. It may be necessary for a new liner to be fitted, so the assessment will also ascertain that this can be installed without snagging on the inner surface of the chimney. “Once the lining is completed, the interior of the chamber can be finished with a simple render coat and painted. The stove can then be connected and tested,” says Richard.
If your home does not have an existing chimney, there are alternatives. “In most cases, a woodburning or multifuel appliance would be sited near an outside wall. The flue would then be taken through the wall at as shallow an angle as possible, rising up the outside of the property to a suitable termination height,” says Peter Mintoft, managing director of Charlton & Jenrick.
Key considerations
Fitting an appliance with a heat output that’s too large for the space is a common pitfall when it comes to stove installations. That’s why it’s vital to bring a professional heating engineer on board, who will be able to do a heat loss calculation to determine the exact size your home requires. “Specifying a stove that’s too large increases the risk of overheating the room or creating soot and tar by slow burning – unless the living space is huge and has low insulation levels,” says Peter. In the vast majority of modern dwellings, you won’t need a model with a nominal output of more than 5kw.
To comply with Building Regulations, you’ll also need to follow the ventilation guidelines to ensure the chimney or flue can draw properly. “In relatively airtight properties, such as new builds, there must be an air vent permanently open to the outside,” says Luke from Stovax. The aperture size will depend on how draughty the house is and the heat output of the stove you’re installing. “In less airtight homes constructed pre-2008, the first 5kw of an appliance doesn’t require an air vent. However, every kw over that requires an additional 550mm2 of free venting.” Note that if the appliance has a draught stabiliser fitted, the figure changes to 850mm2 for every kw over 5kw.
There are also rules about how far away a stove must sit from combustible materials, including timber mantelpieces, joists and plasterboard walls. You’ll find all the guidelines in Part J of the Building Regulations.
The distance between the appliance and combustible materials depends on the model you’ve specified, due to differences in heat output, design and construction of the unit. The regs also dictate the size, thickness and material of the hearth, so be sure to liaise with your chosen professional to confirm that your preferred surface ticks all the boxes.
Who should install my stove?
The best route to ensuring your appliance is safe and meets the Building Regs is to use a suitably-qualified HETAS, OFTEC or Gas Safe-registered professional.
“It’s important that installation and servicing is always carried out by a properly trained and registered competent person,” says Bruce Allen, CEO of HETAS. “Hiring a specialist installer who is affiliated with the relevant body will not only save you time and money, but it will ensure that you find the right appliance for your property and that it runs safely, and at its best capacity.”
As well as fitting your stove and flue, your installer will be a useful source of knowledge when it comes to the upkeep of the appliance. They will be able to provide professional insight on how to get the best performance from your stove in terms of fuel efficiency, plus advice on aspects such as how often to get your chimneys swept.
Time & cost
Typically, the installation of your stove and flue setup will take between one and two days. “Bear in mind when starting building work that this is likely to extend to several days when you factor in the setting of mortars, renders, plasters and the like,” says Peter. “Cutting holes into walls and fitting flue systems are time-consuming activities, so always include sufficient time in your project schedule to get these peripheral jobs completed.”
The average labour costs for fitting a standard flue liner and a solid fuel stove is about £800 – however, this figure will vary significantly depending on the region in which you live and the complexity of the installation. “Most liner and stove installations will require roof access, so scaffolding expenses should be taken into account when budgeting for your installation,” says Richard from Chesneys.