Ventilation for Woodburners

[janitor]

A question for those infinitely wiser than I...

We are currently in the process of cleaning our inglenook up a bit and putting in a double skinned flexible chimney liner above the existing woodburner.

The builder has stated that to comply with building regs, a 9 inch ventilation source should be sited in the outer wall in the back of the fireplace.

While I can understand the reasoning and safety aspect, I thought I'd just ask others whether this is an absolute requirement?

Thanks

Justin

 

[Andrew Bodenham]

The requirements for ventilation are laid out in Approved Document J of the building regulations, which can be viewed and downloaded free from the website of the deputy prime-minister (sorry, haven't got the exact link - do a search)

Table 2.1 states that for a stove the ventilation required is 550mm^2 / kw of rated output over 5kW. In other words, if you have a 6 kW stove then you need a vent with a free area of 550mm^2, which is roughly eqivalent to 1" hole in the wall.

By my rough calcs a 9" hole (assuming 9" diameter with no restrictions) would ventilate a stove rated over 70kW. If your's is that big please post a picture of it so we can all admire it.

Perhaps your builder needs to be presented with a copy of the regs for bedtime reading.

 

[Penners]

if you have a 6 kW stove then you need a vent ... roughly equivalent to 1" hole in the wall.

I wonder whether a slight gap under the door would qualify as ventilation? Or does it have to be to the exterior of the building?

 

[Flyfisher]

As I understand the current rules all wood burner installations must be certified as compliant to the regs. If a HETAS-registered installer does the job, they can certify the work and should ensure a safe and compliant installation. If a non-HETAS person installs the wood burner then you must get building control to certify the installation, in which case an early discussion with your friendly local BCO might well prevent a costly mis-interpretation of the rules. I would also expect the installation instructions for the woodburner to provide specific guidance for the model in question.

 

[AMc]

I would follow your builders advice and get the vent installed near the stove, but make sure it has a mechanism to close it when the stove is not in use.

Our wood burner is not vented. When its lit and burning hard it draws cold air from under the uninsulated, suspended woodern floor through the gaps in the bare floorboards. This can result in the room being +25C at shoulder height with a chilly draft around your feet. If it were easy to vent the stove directly then I would to cut down on the draft and ensure the stove is burning safely.