As they pass through the home up to the roof vertical flues are either boarded over or housed inside a cabinet.
Flue through roof regulations.
And there s a very good reason for this.
Any vertical flue joints if your flue is going through the roof for example must be bracketed with specific flue brackets every 800mm 1000mm.
In the loft it will likely need some type of mesh protection.
Under the boiler flue position regulations the flue has to be positioned a certain distance from any parts of the home that can be opened up such as windows and doors.
That means that it will suck air through from your stove which also helps it to burn well.
As placement of the vertical flue is more complex and convoluted than a standard horizontal flue it is more costly.
In this case the flue goes upwards and then out through the roof.
A vertical flue looks similar to a very small chimney and can be seen spouting out steam when the heating is on.
A roof or any big object really creates eddies swirling patters of air and areas of high and low pressure which can reduce draw.
This means that the flue outlet needs to be positioned sufficiently high above the roof surface and surrounding buildings to prevent it being affected by wind eddies or downdraughts.
Also at every joint.
If the flue exits the roof further down then it must extend high enough to acheive 2 3m of horizontal clearance.
The building regulations identify the zone for this but any of these dimensions may need to be increased where there is exposure to.
A venting system shall be designed and constructed so as to develop a positive flow adequate to remove flue or vent gases to the outdoor atmosphere.
Vertical flue joints in attics must be bracketed.
The above points only really apply for flues that exit the home horizontally through a wall but that doesn t mean there aren t any regulations if your boiler flue goes vertically out of the roof.
How high does the flue have to go.
If the flue passes through bedrooms it should be boxed in with an inspection hatch situated in a specific place.
A gas vent shall terminate in accordance with one of the following.
When installing a new twinwall flue system if the flue exits the roof within 600mm horizontally from the ridge high point of the roof then the flue must extend a minimum of 600mm above the ridge.
To get a good draw you need a tall enough chimney and to raise the end of the chimney or flue up away from the roof.
How far this is will depend on the size of your boiler but is typically between 30 60cm above below or to the side of an opening.
Above the roof surface with a listed cap or listed roof assembly.
