Turner Baker’s Chimney Construction
A chimney is an integral feature of most houses – even today, with different sources of heat available, chimneys are still added to newly built properties. Sometimes they are purely decorative, but mostly they are designed to accommodate a flue for a woodburning stove, gas or open fire.
Good chimney design and construction goes beyond adding a structure that looks in proportion to the top of a property. Chimney design is an age-old pastime and applies to the grandest of houses down to the smallest of cottages, but it requires an understanding of thermodynamics to get a chimney and flue working properly.
As you can see from the diagram, a chimney can hold one or more flues. Chimneys in large old houses often house multiple flues going off in various directions to service lots of fireplaces in different rooms. Each fireplace, boiler, stove or gas fire must have its own flue. This picture shows two flues, one for a boiler at ground level and one for an open fire on the level above.
Ideally, a flue should allow hot gases to vent into the atmosphere as quickly as possible, any bends in a flue are likely to slow the progress of the gases and could become a depository for creosote to build up and increase the risk of a chimney fire.
Any flue that is designed as part of a new build project must be lined to comply with Document J of current building regulations. There are also stipulations within current building regulations on materials that can be used, distances between flues and distances between flues and combustible materials e.g. wooden lintels.
It’s all in the design
It is becoming more common for architects to be asked to include an open fire, wood burning stove or gas fire into a property renovation or new build – the idea of cosying up around a fire in the autumn and winter months is something that endures in our traditional British culture.
Many architects now ask for specialist help from a chimney expert to ensure that the size of a fireplace opening is correct for an open fire, and the length and width of the flue are correct for whatever system the homeowner wishes to use.
Turner Baker can work closely with architects on all aspects of chimney and flue design. We work with CAD and can provide professional quality designs with all the dimensions required. This includes specifying flue and vent sizes.
One of the chimney problems that we are regularly asked to provide consultancy on which is very important to get right at the design stage – is getting the correct flue size. This is true for whatever appliance you are using the flue for, a boiler, stove, open fire – if the flue size isn’t correct, it won’t work properly and could prove dangerous. As an example, if you are hoping that a multi-fuel stove that requires a 6” flue liner will work fine if fitted to a 12” diameter unlined chimney, it won’t. The smoke will slow down immediately as it leaves the multi-fuel stove into the large unlined cold flue and you will very quickly find a dangerous build-up of tar and other deposits on the sides of the chimney.
The other downside of attaching a stove to an overlarge flue is that it will affect the draw. The smoke will slow down and cool as the flue is too large to draw the smoke away from the multi-fuel stove efficiently and it won’t work nearly so well. The temperature of the flue has an important role to play in the efficiency of a multi-fuel stove – if it’s too big the smoke will cool straightaway and it won’t draw the smoke away from the fire.
Supply of materials
Chimneys and flues come in a range of different formats from a simple stainless steel flue exiting the side of a property to a built-in flue system that can be encased in a brick chimney.
There are various clever flue and chimney systems available now that can be installed by the building contractor as part of the overall build project. These systems can be specified and supplied and expert advice can be given to the building contractor on the project so that they can install the product. This is especially useful where clients are looking for something with greater longevity than a stainless-steel flue.
Turner Baker is able to work as a part of a wider team on many of the projects that we are asked to advise on. This is particularly relevant for renovation projects where existing chimney stacks are being re-opened or altered to be incorporated into a new scheme.
We have various lining solutions which lend themselves to heritage projects which need to be installed by a professional chimney company. Our teams have worked on projects from Devon up to Cheshire, in Wales and all over the South East. We are flexible in our approach and work hard to fit into the team and build schedules for each different project.
Getting it right first time
Ultimately, we would like to work with architects to make sure that any chimneys and flues specified work correctly from the moment the project is completed. Sadly, all too often we get calls from homeowners who are excited to be in their new home but disappointed to find that a fireplace or flue doesn’t work properly.
Solutions to this can often be found but at additional expense and upheaval to the homeowner.