Recommend chimney cowl?

[Jack07]

Hi,
I need to cap off a couple of chimney pots. Can anyone recommend whats best to use?

Ive been looking at the C-caps. Anyone used these?

Also I have 2 chimney breasts, downstairs a gas fire and a removed fireplace(vented), upstairs I have 2 disused fireplaces.

As a complete novice, how do I find out which chimney pots serve which fireplace? The last thing I want to do is cap the gas fire.

Is it as simple as turning on the gas fire and feeling for heat or smelling for clues?

Any advice would be greatly appreciated.
Thanks

Jack

 

[Alastairreid]

Smoke test the vents, you can get pellets from plumb centre or some builders merchants.

Vented terminals are best for closing off redundant flues imo.

piccy

Untitled

• Alastairreid
• 17 Jul 2009
• 20

 

[joe-90]

But what's the benefit? I've never had a problem leaving them open - and there are millions of them out there that don't.

 

[Jack07]

The house is an ex-council house (1920-30s). Had a few damp problems and suffers from heat loss.
Just trying to improve as many of the problems as possible.

Was hailstoning the other night when I was putting my boy to bed and could hear hails pinging down the fireplace in his room, thought 'this doesnt sound great'

 

[Alastairreid]

But what's the benefit? I've never had a problem leaving them open - and there are millions of them out there that don't.

The Building Research Establishment (BRE) recommends disused chimneys should be capped off at the top with a ventilated capping.

Where a disused chimney is left uncapped, it is open to the UK weather, which annually can be relied upon to deposit several feet depth of water down the average chimney. This can give rise to damp stains appearing internally and over time it contributes to steady internal deterioration of the fabric of the stack.

 

[joe-90]

But every post in here we get with condensation in the stack is ALWAYS capped off. There are more open stacks than people in this country - so why waste money capping something that invariably gives more problems than it solves? When you factor in parts and scaffolding it comes to near a thousand quid - for what?

Several feet of water? FFS - what a load of rubbish.

 

[Alastairreid]

The last thing I want to do is cap the gas fire

The vent for your gas appliance should have the appropriate vent terminal fitted.
This serves a similar purpose to the caps for the redundant vents ie debris dropped by nesting birds, rain ingress, and back draught.

 

[Jack07]

The last thing I want to do is cap the gas fire

The vent for your gas appliance should have the appropriate vent terminal fitted.
This serves a similar purpose to the caps for the redundant vents ie debris dropped by nesting birds, rain ingress, and back draught.

Just before you posted I had a look and there are 4 pots, 2 are standard with mesh on top, 1 I cant see from the ground but pot has definately been removed and the last one I can just make out has a small metal cowl, I imagine this one to be the gas.

I will pop up and have a good look.

Thanks for advice

 

[Alastairreid]

the last one I can just make out has a small metal cowl, I imagine this one to be the gas.

Probably a GC1 http://chimneyproductsdirect.co.uk/index.php?page=product&pid=87&cat=2&range=1

You can cap the other 3.

 

[tim00]

With respect Alastair, jack noted "a small metal cowl" ie. sounds like an insert terminal not a GC1, but without a pic one cant say if it's for gas or ventilation.
Someone has to determine in-situ on the roof exactly whats what.

As regards the cap off or leave open debate. For me the pros are, caps keeps birds out, and lack of caps is often noticed by surveyors. I doubt the water ingress and backdraft requirements. Backdrafts are a whole area of other technical difficulties.
Thing is, if work is going on at the stack i would cap off, but i wouldn't recommend it as a stand alone job. Only go on roofs if necessary.

 

[catlad]

I think if you leave your chimney's open when no longer in use is foolish, look at all the bucket lying around in your garden/yard when its been raining, thats a similar diameter to your chimney pots and look at all the water they collect.

 

[joe-90]

They've been like that for a thousand years. There are about 80 million in the UK. They aren't causing any problem.

 

[Xenon]

They've been like that for a thousand years. There are about 80 million in the UK. They aren't causing any problem.

They would also have had a regular fire drying the stack out wouldn't they?

As mentioned earlier, vented cap is the correct way to solve the problem originally posted. Also as originally suggested a smoke bomb will identify the offending pot (s)

 

[joe-90]

Not in summer. Cowls cause more problems than they solve. I've got open pots - not a bit of a problem. They cause condensation issues. Just check the posts in this forum.

 

[Xenon]

Yes Joe, i'm very pleased you haven't got a problem, thats really great. However, the fella who posted originally does have, so, using his noggin, he came and asked for a bit of advice. Now, call me wierd if you want, but i think he was given some sterling advice from intelligent people, whereas your advice seems to be merely based on your house . The cowls recommended were vented, that will still draw...gives a bit of air which helps a lot. But as i said, really glad yours are fine, well done you......have a biscuit.