Flue installation and chimney
systems across the North East

Why liner diameter matters

An old masonry flue built for an open coal fire is far too wide for a modern stove. The gases spread out, cool and slow down, so the stove draws badly and tar condenses on the way up. A liner sized to the stove keeps the gases hot and moving.

Many Ecodesign stoves approved for smoke control areas can run on a 5 inch liner, while others need 6 inch. The stove's installation manual decides, and we follow it. Fitting the wrong size to save money is the most common shortcut we find when called to put right somebody else's flue installation.

Insulating the liner

On a cold external stack, or a tall one, insulation around the liner helps the flue warm up quickly and stay warm. That improves draw on lighting and reduces condensation. Whether it is needed depends on the stack, and we tell you at the survey.

Twin wall flue installation: inside or outside?

An internal route runs up through the ceilings, usually through a bedroom or cupboard above, where it is boxed in to the correct clearances, and out through the roof. It stays warmer, so it draws well, and it is less visible from outside.

An external route goes out through the wall behind the stove and up the outside of the house. It avoids work in the rooms above but is more visible. On each twin wall flue installation we weigh both options against your layout and show you where each would run before you decide.

Outlet height and position

Building Regulations set minimum heights and distances for the flue outlet in relation to the roof, nearby windows and neighbouring buildings, so that smoke disperses properly and does not come back into your house or next door.

The approved documents set the detail. Getting the outlet position right is part of every flue installation we design, particularly on bungalows and extensions where the roof is low.

What flue installation costs

On a typical job with a serviceable chimney, the liner, closure plate and cowl are included in our stove price, from £2,199 fully installed where the chamber is already the right size, and in every stove package. Twin wall systems are priced individually after the survey, because the route and height decide the cost. Every price is fixed in writing before anything is booked.

Liners need sweeping too

A lined flue still needs sweeping, at least once a year, and more often for wood in regular use. Soot and tar build up inside the liner just as they do in a masonry chimney. The National Association of Chimney Sweeps lists qualified sweeps, and your insurer may ask to see a sweep certificate.

How long does a liner last?

It depends on the grade and what you burn. A good liner on dry, seasoned wood lasts many years. Burning smokeless fuel on a 316 grade liner shortens its life, because of the acids produced, which is why we recommend 904 grade if you plan to burn smokeless fuel. Wet wood shortens any liner's life.

When a flue installation needs replacing

Signs include smoke into the room, cold downdraught when the stove is not lit, tar staining on the chimney breast, or a liner that has visibly corroded at the bottom. A new stove often needs a different diameter too, so the existing flue may not simply carry over. We check it at the survey and tell you honestly whether it can stay.

Flue installation in different kinds of property

Terraced houses often share a stack with next door, so we survey the whole stack, not just your flue. Single-storey cottages and bungalows can have short flues, which may need extending to draw well.

In Tyneside flats the flue from the downstairs flat passes through the home above, which needs your neighbour's agreement. Garden rooms and extensions usually need a twin wall system with careful attention to distances from boundaries and combustible materials.

Whatever the property, the same HETAS registered team designs, installs and tests the flue, and you can check our registration on the HETAS register. Book a free survey and we will tell you exactly which flue installation your property needs, with a fixed price in writing.

Building a twin wall flue

On a twin wall flue installation the sections are assembled from the stove upwards. Each joint locks together, supports are fixed at set intervals, and where the flue passes through a ceiling, floor or roof, a fire stop and the correct clearances to combustible materials are maintained.

On the roof, a flashing seals the flue to the tiles or slates, and a storm collar and terminal finish it off. Inside the house, the boxing around an internal twin wall flue is built to keep the required clearance, and can be plastered and painted to match the room.

Testing before sign off

No flue installation is finished until it has been tested. We smoke test the flue to check for leaks, light the stove and check the draw, and confirm the carbon monoxide alarm works. Only then do we issue the HETAS certificate and notify the council.

Keep that certificate safe, because it records exactly what flue installation was carried out, and your insurer, your sweep and any future buyer may all ask to see it. Store it with the stove manual.

Ventilation

A stove needs air to burn, and the flue can only draw if that air is replaced. Above five kilowatts a permanent air vent is required by Building Regulations, and in very airtight modern houses one can be needed below that.

Some stoves can take their combustion air from outside through a direct air kit, which suits airtight homes. We check this as part of every flue installation and include any vent in the written price.

Who does the work

We do not fit an appliance and leave the flue to somebody else, and we do not subcontract the roof work. The same HETAS registered team that surveys the property designs the route, supplies the components, carries out the flue installation, tests it and issues the paperwork. If anything needs attention later, it is the same team that comes back.

Book a free survey, in person or from photos of the chimney breast and the outside of the stack. We will tell you which flue installation your property needs, and give you a fixed price in writing with no obligation.