capping disused chimney

[Stephen Birkbeck]

Does anyone have any thouhgts on the most cost effective way to cap a disused chimney? House is victorian with a square pot. Do I need a vent brick at the base or just at the top.

Thanks

Steve

[Rob graham]

I would, as a principle, want to ensure a good airflow through any space that might accumulate dampness. Therefore an airbrick at the top and the bottom would allow air to move freely and take moisture with it.

Rob Graham

[Andrew Gabriel]

Must be vented top and bottom. Proper ventilation is much more important than capping.

If the chimney is on an outside wall, I would suggest venting to the outside rather than in to the room, as a an open flue in a room will create its own updraft and hence lose some heat/energy from the room.

[Stephen Birkbeck]

Any ideas for capping the top, bearing in mind that it has a sqaure pot. I was thinking about putting a paving slab under the pot and a vent brick under the slab. Anyone done this?

[fred]

In article , Stephen Birkbeck writes

I've seen it done with a slate, mortared in place (on top), seemed to work & v unobtrusive but then you still have to vent.

The other option would be to fabricate a square version of these:

, just use something to stand it off the pot a little, leaving a gap for airflow.

Also, these guys:

have a huge range of cowls, may be worth a call or email to see if they can help with a square version or maybe a large round hat could be adapted.

On Andy's point about venting the bottom of the chimney to the outside, I'm not sure that will create enough airflow, my thinking is that the vent to the inside (and warm air) is needed to create the updraught that will keep the chimney dry. That said you are stopping rain entry so how much airflow is needed?

[Stephen Birkbeck]

Cheers Fred

Might just go with the slate option, seems easy enough.

Steve