Blocking of chimney

nailer54321

As title says, have a down draft from chimney, was just wondering would it be ok to put a cap on top of chimney to compleatly block it. I don't use gass fire or will ever use fire. Is it ok to block this off or am i missing anything. Just makes sense to me to block this off to stop draft coming in from chimney. Anyone ever done this. Is there any cons to doung this?

martyc5674

nailer54321 wrote: »

As title says, have a down draft from chimney, was just wondering would it be ok to put a cap on top of chimney to compleatly block it. I don't use gass fire or will ever use fire. Is it ok to block this off or am i missing anything. Just makes sense to me to block this off to stop draft coming in from chimney. Anyone ever done this. Is there any cons to doung this?

Currently the chimney is providing ventilation to the room. The question you need the answer to is- Is there enough ventilation in the room without the chimney.

nailer54321

@matryc5674, there is a vent in the room and doors between rooms are mostly open, just wondering is that enough ventilation, would like to block chimney bur was wondering the same about ventilation.

con747

You could look at something like this, https://purchase.ie/product/all-products/chimney-capping-cowl

nailer54321

Was wondering if there is anything like a plate that would just stick or screw on top of the chimney, had a spinning crowl before and it blew of when we has very high wins a few year back so dont want to attach any more heavy crowls on.

Thoie

Chimney balloons were all the rage a few years back, but haven't heard anyone mention them recently.

https://www.mcmahons.ie/chimney-balloon

nailer54321

Thanks for that, but looking at blocking chimney compleatly. Was just wondering if there would be any disadvantages to do this eg. Dampness developing or condensation.

con747

nailer54321 wrote: »

Thanks for that, but looking at blocking chimney compleatly. Was just wondering if there would be any disadvantages to do this eg. Dampness developing or condensation.

The link to a slightly vented chimney cowl I posted earlier looks best according to this article unless you fully block both ends, but I am not an expert!

One old and virtually free method of capping off, or sealing a chimney that is generally no longer used is to make a lead cap. These can simply be made out of a scrap or an offcut of lead, beaten into the correct shape and bonded to the top of most chimney pots to effectively seal it and make it waterproof. The reason this really isn’t used anymore is that sealing the pot to make it water and air tight can cause internal condensation, especially if the flue is open inside the property. If this is the case warm moist air may rise up the inside of the flue, condensate and drop back down into the property or create dampness in the brickwork of the flue itself, possibly showing itself internally at a later stage.

chooseusername

con747 wrote: »

The link to a slightly vented chimney cowl I posted earlier looks best according to this article unless you fully block both ends, but I am not an expert!

One old and virtually free method of capping off, or sealing a chimney that is generally no longer used is to make a lead cap. These can simply be made out of a scrap or an offcut of lead, beaten into the correct shape and bonded to the top of most chimney pots to effectively seal it and make it waterproof. The reason this really isn’t used anymore is that sealing the pot to make it water and air tight can cause internal condensation, especially if the flue is open inside the property. If this is the case warm moist air may rise up the inside of the flue, condensate and drop back down into the property or create dampness in the brickwork of the flue itself, possibly showing itself internally at a later stage.

Make a dome shape of the lead to throw the rain off,and
hammer nail holes upwards through it to allow the warm moist air out .
Clip on with this;

listermint

Ive blocked 3 chimneys on mine recently. Two fire and old agaa chimney.

C Cap on top of chimney. I pulled the bottom in the room with a shaped piece of EPS. And then filled the entire stack with loose EPS ball fill same stuff that is used in cavity fills without the glue.


So the entire thing is blocked off now and can be reversed very easily by pulling the plug in the room.


I had balloons before this but they keep on going down and can get sucked up often by high wind. Crap.

nailer54321

Thanks for all your replys, was thinking condensation could be an issue if i blocked it off compleatly, will have to look further into this.