It’s that time of year when I love nothing more than relaxing in front of our fire with a glass of something or the other. A radiator just isn’t the same! If you don’t already have a working fireplace or wood burner, it’s perfectly possible to add one to your home. But you’ll be needing a chimney.

A chimney vents ash and unwanted (potentially harmful) gases from your house. You must have one if you have a working fireplace, furnace or heating stove that burns any kind of combustible fuel. It’s absolutely vital that it works properly to ensure your safety and also the efficiency of your appliance.

Planning your chimney

I’m sure you won’t be too surprised to know that there are various regulations you need to comply with when building a chimney. For some light reading, take a look at The Building Regulations Approved Document J. These regulations cover things like the height of your chimney and the clearance it must have from combustible materials. The rules vary slightly depending on the type of building and the type of appliance. Barn conversions, for example, often require a metal chimney above the roof to meet with planning regulations.

If you’re looking to add a chimney to an existing building, you could have a traditional structure built on the inside (although this could be complex), or outside of a suitable wall. Or you could add a stainless steel, insulated, purpose-made flue. The best way to install a flue during the conversion of an old stone building, for example, might be to put a flue right through the centre of the house. Heat is more efficiently used throughout the house and the top of the flue will be near to the ridge.

As a rule of thumb, the taller the chimney, the better it drafts.

A chimney can be brick and masonry or metal. Masonry chimneys are typically lined with clay or ceramic tile flue which goes up the centre of the brick chimney with a gap between the two layers.

You can build one chimney for several appliances and connect them to one main discharge flue (within certain parameters) but the appliances must be emitting the same type of by-product (e.g. you can combine a gas range with a gas furnace, but not a wood-burning fireplace).

Building your chimney

When building a new chimney, start from the ground up. For masonry chimneys that usually means building the chimney smoke chamber on top of a fireplace using a brick similar to that used to build the hearth. Take a look at our blog on building a brick wall for some tips on laying your bricks.

Building your fireplace could be part of this process. A well built fireplace can be a very beautiful feature in your home.

The flue connects the top of the smoke chamber to the roof. It’s important to line your chimney. You can use metal or concrete liners.

Surround the chimney with metal flashing where it goes through any walls, where it meets the roof and as a lining underneath the chimney cap. You’ll need to make sure everything is sealed properly to stop water from leaking into the house. You’ll also need to cap the chimney with a cap that extends past the chimney wall and has a drip edge to channel water away from the chimney.

Why you should use a builder to build your chimney

We’ve rather sped through building a chimney because we strongly encourage you to get professional help for three very good reasons:

The safety aspect: it’s so important to make sure your chimney is built correctly. If there are any errors you risk dangerous gases entering your home rather than being drawn away, and you risk your house burning down. Not good.

The regulations aspect: the regulations are there to keep you and your family safe, but you also need to comply with them to avoid being fined or having to do the work over. A good builder will know the regulations and how to comply with them.

The falling off the roof aspect: by its very nature, building a new chimney will involve some work at height on your roof. Builders will know how to carry out this work safely.

If you’re having a new brick fireplace built along with your chimney, it will become a focal point of your home. Getting a professional to take care of that aspect of your build will also ensure that your new fireplace looks spectacular. Well worth it for the enjoyment you will get from sitting in front of your new fire whilst enjoying a glass of something or the other.