Cavity Wall

[wendigo100]

Before cavity wall insulation the two vents in the inner and outer skin could be offset thus using the cavity as a baffle. If you fill the cavity the two vents have to be directly connected and the easiest way is on big hole straight through, and there we are back to the begining of the thread.

Thank you. I assume that was in answer to my question, rather than to the quote containing Zeity's insect report.

[The Lone Gunman]

Indeed.

Floor vents are sensible.

Drilling fecking big holes in walls isn't.

There a foot square hole behind the radiator in my living room... the draught is truly stupendous.

And it aids the ingress of wasps and bees, not to mention the mouse that I found under the gas fire.

Before cavity wall insulation the two vents in the inner and outer skin could be offset thus using the cavity as a baffle. If you fill the cavity the two vents have to be directly connected and the easiest way is on big hole straight through, and there we are back to the begining of the thread.

[The Lone Gunman]

My mate has a coal burning central heating boiler which has vents under the floor to feed it with air.

His cavity wall installers wanted to drill a similar enormous hole in his wall for no good reason & block up the existing vents...

I am using floor vents from the celar, then celar vents to the outside world. The air has to come in somewhere.

[wendigo100]

Is this a cavity wall requirement, this hole, or are they saying that everyone with a fire should have one regardless?

[The Lone Gunman]

Why not install the vent next to the fire - or in the fire - so the o2 is immediately burned without creating a draught in the room.

There is a minimum distance required so that enough O2 is in the room even if the fire burns vigorously (more than the vent can supply).
Most modern fires have O2 depletion sensors and switch themselves off, but coal doesn't.

That is about as far as my knowledge goes on this so don't ask me any more.

Google is your friend.

[lilelvis2000]

It is not about CO2 extraction, it is about o2 induction.
If there is a chimney in the room then there is already a very large hole drawing air (and any gasses out of the room), but if you have a fire burning with no air induction then the O2 gets burned up.
You have to have enough ventilation to feed the fire.

Why not install the vent next to the fire - or in the fire - so the o2 is immediately burned without creating a draught in the room.

[MrsGoof]

ring the building regs guys at the local council

[The Lone Gunman]

It is not about CO2 extraction, it is about o2 induction.
If there is a chimney in the room then there is already a very large hole drawing air (and any gasses out of the room), but if you have a fire burning with no air induction then the O2 gets burned up.
You have to have enough ventilation to feed the fire.

[Back In Business]

i stuff £20 notes into my cavity.


threaded

too much information

[lilelvis2000]

two steps forward and one back.

I'm not surprised. Rather can install a heat exchanger..which can keep the heat in the house whilst bringing in fresh air .. a very Victorian solution is used.

[kramer]

i stuff £20 notes into my cavity.


threaded

[Troll]

I had a Gas fire installed and the installer insisted on putting a huge vent through the wall which as you rightly say negates all the benefits of heating / insulating.

I taped mine up which probally means I will die a horrible death but did invest in a CO detector next to the fire
HTH

[hyperD]

I wonder whether anybody has any info that could help...

Just had cavity wall insulation put in (which was nice), but they insisted on drilling a hole in the wall because we have an open wood/coal fireplace with a chimney. This is down to "...building regs, mate..." which is fine I guess to minimise the possibility of the Darwinian death of a numpty in a broom cupboard with a pokey Homebase gas fire... but I digress with my cynicism.

The main issue I have is that drilling a large whole in the side of the wall with a plastic vent has negated all the effectiveness of cavity wall insulataion and the living room is freezing. I've taped up the vent for now.

Despite looking on the net, cannot find anything to tell me whether this applies to:

1. Wood fireplaces with chimney and not just gas fires (although in theory poorly ventilated wood fires can generate CO).

2. Whether we can purchase a glorified cat flap.

To be honest, after the building inspection, I'm going to seal the hole up as it's ridiculous - you can hear the wind blowing into the room now, the entire downstairs is large and totally opened up and in the last 7 years we haven't died yet, although the wife is working on it.

(where's MikeTheBike when you need him)