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Chimneys & Fireplaces

Does chimney have to go straight up?

Are there strict regulations/ recommendation on how chimney should be setup?

6 Answers from MyBuilder Chimney & Fireplace Specialists

Best Answer

The straighter the chimney the better it works and at least 80% of the chimney must be vertical.

In a factory made system (twin wall flue) there can be a maximum of 4 bends with a 45 degree bend counting as one and a 90 degree bend counting as two.


Answered 12th Jun 2019

The best thing to do is download the Document J Building Regulations England Ni Wales. All the info you could possibly need to know is located there. Scotland has slight differences but pretty much follows the same legislation.
Some pretty good answers to be found on my builder also.
Good luck Clare 🍀


Answered 12th Jun 2019

The answer is yes a chimney must go up but it can have some bends in it , very rare you will get a straight chimney


Answered 13th Jun 2019

Download 'Document J Building Regulations'. This will show you all the information you need and chimney length from roof etc.


Answered 13th Jun 2019

Hi Clare

The straighter the better. Lots of chimneys can work being under the recommended height of 4.5 meters. But you can pretty much assume it will work at that height.
The problem with this is that if a twin wall system is coming out of a singe story building. 4.5 meters looks awful. I advise my customers that we will keep it low enough towork. If they have problems down the line, then add some more height. By simply adding a section.that will keep cost down in the first place.hope this helps. Chris


Answered 12th Jun 2019

If it’s a flue pipe they like have 600 straight before bend . If open fire most fires go straight for around meter then bend of left or right. there should be minimum 4.5 meters recommended no more four bends two changes off direction always do smoke test to check draught and leakage . You should do draught reading to check meet stove manufacturers requirements


Answered 12th Jun 2019

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