Chimney Vents

[thebadger7]

Hi all

I'm looking at add exterior vents into unused chimney flues, as chimneys are on gable ends. 3 floors = 3 flues. I've read it's better to do externally, as interior air hols more moisture and you don't lose heat doing it externally.

Not really sure best way of doing this. Is is just a case of drilling a few holes in the middle of chimney from outside and add a louvre grill? There will be three for the three stories.

Thanks!

 

[ree]

OP,
Why not post pics of the gable, and, if possible, the chimney stack pots?
I prefer internal vents in all redundant fireplaces, these vents will allow each flue to be definitely vented without possibly damaging the flue feather(s).
Neither do you want cold air in redundant flues or for that matter, for the same reasons you dont vent cavities in cavity walls.
Redundant flues should be swept before being vented at the bottom and the top.

 

[thebadger7]

Thanks, here you go. Chimney having some work done - pots will all have cowls on, flaunching etc. Old kitchen one side, clear gable the other.

There's a line of thinking that it's better to vent externally as outside air has a lot less moisture than inside warm air, which may well then condense on the inside of the flue. But my main motivation is to reduce heat loss, have scaffolding up at the moment so now's the chance.

 

[ree]

OP,
Thanks for the quick pics.
There's an available range of ventilating cowls for redundant flues. Clay cowls that sit in the pots are best.
Definitely dont install external air venting - the scaff is irrelevant for two air bricks because, to work, they would have to be installed in the shed on the ground floor
As my above, sweep the flues, and if the fireplaces are to be blocked off then installing Hit&Miss vents in the fireplace blocking is usual.

 

[thebadger7]

Why would the vents have to be installed on the ground floor?
House is three stories, so I'd assumed it would be a vent at each level

 

[Nige F]

Checking through the old threads I found bobasd was advocating external air bricks.