Building a chimney breast is one of those jobs best left to a professional. It is incorporated into the structure of the house and anything but the most superficial of repairs will need the expertise of a skilled bricklayer. The chimney and flue carry with them toxic gases such as carbon monoxide and sulphur dioxide and it is vitally important that these gases do not permeate through the brickwork and into the house where unconsciousness and death can result if the gas levels build up. Because of this, it can be impractical and unwise to build a brick chimney from scratch. Often, if the house never had a chimney in the first place or if the existing chimney is just too far gone to repair, it often works out cheaper and safer to make a hole through the gable wall and using a standalone stainless steel flue pipe, run it up the outside of the house and extend it past the top of the roof line. That way you get over the problem of building a chimney stack as well as ensuring the gases remain outside and separate from the house interior.
If you have your heart set on building a new chimney it will need foundations, scaffolding and a labourer to assist the tradesman as well as plans and building control. Check that planning permission isn’t required as well. To build this properly will require up to 3 weeks work and cost in the region of £7000. In addition, the building control permit will cost about £250.
Rather than go to the expense of building a new chimney or repairing an old one it may be more cost effective to remove the existing chimney, use the additional space and install gas central heating.
Once the calculations and plans have been completed and the approvals have been granted it is now possible to start work.
The proposed costs to do the work will depend on the extent to which the chimney is being removed.
|Type of Chimney Removal Job
||Estimated Time (days)
|Remove first-floor chimney breast only||3 days for 2 men||£1500 + materials|
|Remove ground floor chimney breast only||4 days for 2 men||£1800 + materials|
|Remove entire chimney breast leaving the stack in situ||5 days for 2 men||£2100 + materials|
|Remove chimney stack||3 days for 2 men||£1500 + scaffolding & material costs|
|Making good walls, floors and ceilings & plastering||1 day||£500|
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Remember that the chimney removal prices given in the table are indicative only and will vary depending on other on-site issues that may occur. Scaffolding is a big cost that needs to be covered or you could consider using a cherry picker for access instead. By careful discussions with your builder, about access considerations, it may be possible to greatly reduce the cost to remove a chimney stack.
As usual with any building work, the average cost of chimney removal will vary depending on where in the country you live and will always be more expensive in London.
Although is it possible to remove a chimney as a DIY project, it is advised to leave it to a professional. The specialist knowledge required to do a safe and professional job is an absolute ‘must-have’ and is not something the average DIY enthusiast can do to save money. Basically, if you aren’t sure what you are doing and you have never done it before, leave it to the professionals. You won’t regret it.
Why Remove Your Chimney?
Your chimney is a relic of a bygone era. These days the vast majority of households in the UK are heated by gas or oil-fired central heating boilers which usually have their own method for getting rid of exhaust gases via a flue through the wall. If you have a log burner or multi-fuel burning stove it will need a chimney to carry away the exhaust fumes and soot otherwise the chimney is often forgotten about and falls into disrepair. Combine this with the fact that there is no longer any heat coming up the chimney and you have a perfect place for damp to find its way into the house. Bricks start to erode and lead flashing deteriorates with the extremes of weather and before you know it there is a big wet patch on the bedroom ceiling. Chimneys even start to crumble, with bricks and chimney pots falling onto the roof causing extra damp problems from broken roof tiles and slates. Why bother spending out on unnecessary maintenance if you don’t have to. It is also an extra weak point in the battle between the cold, wet outdoors and the warm, dry indoors.
Not only is there a problem with unused chimneys letting in the damp, but you also have a problem with the chimney breast using up a lot of space within the house. With space at such a premium in modern homes, it seems pointless to waste it, and it is not just the living room that has a chimney breast, upstairs bedrooms lose the space as well. With all these points working against chimneys, it is no wonder that homeowners are thinking more and more about chimney breast removal costs and prices for removing chimney stacks from the roofs along with the logistics of doing the work in the first place.
The Working Parts of a Chimney (more complex than they look)
Chimneys, although relatively simple at a first glance are a complex piece of construction engineering that has been developed over many thousands of years. What was once upon a time just a hole in the roof has now changed into an architectural achievement controlling ventilation and the fluid dynamics of gases. Even the word ‘chimney’ is a vague term that covers the entire construction running from ground level to above roof height, when in fact the construct comprises many parts that individually are indispensable for the chimney to fulfil its function. The main parts of the chimney comprise:
- Hearth: This can be considered as the base of the chimney and incorporates part of the fireplace. The hearth surrounds the fireplace opening and provides a heatproof section of the floor. It is usually surrounded by a very low border wall to prevent ashes and embers from encroaching onto the remainder of the room.
- Fire cradle: This is the part that holds and contains the coals and embers. It is made from metal mesh or slats to allow free movement of air from below into the fire and free movement of ash from the fire cradle into the hearth.
- Chimney breast: This is the outside limit of the chimney, enclosing the flue. It usually protrudes into the house on all floors from the ground to the roof but can sometimes protrude outside as well.
- Flue: This is the centre tube that carries the smoke away. In cross-section, it can be square, rectangular or round depending on whether it has been built using rectangular fire bricks or has been lined using interlocking firebrick earthenware tubes or a metal liner.
- Chimney stack: The stack starts in the roof space and continues through the roof, above the roofline. The height of the chimney stack is designed so that there is no downdraught to interfere with the safe removal of the smoke.
- Chimney pot: This is an earthenware cylinder fitted to the top of the stack. It has two purposes. To cheaply extend the smoke exit hole higher than the top of the chimney stack and to improve the chimney’s draught. Chimney pot prices are very reasonable and are a very cheap way of sorting out many chimney problems.
- Chimney pot cowl: This is a shaped cover for the chimney pot that increases the efficiency of smoke removal from the pot and prevents birds from nesting in the chimney. They often incorporate a rain baffle to prevent snow and rain from entering the chimney and a wire mesh to prevent sparks from rising out of the chimney. Two of the commonest shapes are like a capital letter H which is a fixed cowl and a curve similar to a lobster tail which is allowed to freely revolve with the wind. These also prevent backdraughts of wind blowing smoke back down the chimney.
A typical chimney works by the following method.
- Hot air rises up the chimney from the fire causing an area of low pressure at the fire cradle.
- This draws cool air from the room, across the fire and up the chimney.
- The hot air rising from the fire takes with it all the toxic combustion fumes and solid soot particles.
- As the hot air rises in the chimney flue, the air cools until it reaches the chimney pot.
- When the exhaust fumes and soot reach the fresh air, they have cooled enough to blend easily with the surroundings.
- The cool air drawn through the fire cradle ensures that there is enough oxygen for the fuel to be burnt efficiently thereby reducing the number of toxic fumes produced and increasing the heat given off into the room.
Chimney Breast Removal – The Most Expensive Part
If you decide to remove the chimney remember that although it is relatively cheap to remove the stack it can be very expensive to remove the breast. All that is required to remove the chimney stack above the roofline is to take away the bricks one by one until the chimney stack removal is complete, beneath the roofline and inside the roof space. The roof can then be repaired to cover over the hole.
The breast, however, can be extremely expensive to remove. Unfortunately, the chimney breast is usually incorporated within the structural envelope of the wall when it was initially built. Because of this, you can’t just remove the breast in the rooms otherwise part of the wall and the stack above will be left unsupported. You must consult a structural engineer and use his or her calculations along with help from an architect to produce proper working drawings for a builder to work from. Once the drawings have been done, they must be approved by the local planning and building control departments of the local council. On no account start to remove any part of the chimney until you have the approval of the relevant authorities. Yes, this will cost extra time and money but it is a process that is there for your safety and for the safety of future owners of your home.
Before the removal of the chimney breast and stack takes place, you must have the inside of the flue cleaned by a chimney sweep to remove soot and acidic sulphur deposits. If this step is missed, then the process of removing the chimney will be very messy indeed. To ensure you get a professional job done it is always best to employ a fully qualified member of one of the chimney cleaning professional associations such as the Guild of Master Sweeps. All their members are all fully insured and will issue an insurance company approved certificate to prove the chimney has been cleaned. This is very important if you are just having a chimney cleaned before lighting a fire.
The average chimney cleaning cost will be between £40 and £60 depending on the chimney height and how easy it is to access the top or bottom. If you have a wood-burning or multi-fuel burning stove then there may be problems getting the brushes into the chimney from below. In this case, the sweep will have to clean from the rooftop end rather than from the hearth end. A fully qualified sweep will always know the best method of how to clean a chimney depending on your personal situation. If you have more than one chimney in the house, the cost to clean both will usually be less than cleaning two independently.
Remember that building or demolishing a chimney is a skilled job and should only be attempted by a professional.