Blocking up a flue

[Softus]

On a similar subject to this topic:
http://www.diynot.com/forums/viewtopic.php?t=125037

... I have a customer with an open grate in the lounge, who wants to stop (or radically reduce) heat loss up the chimney, and without the expense of going onto the roof.

What is permitted, and practical, in terms of constricting the opening in the fireplace on the ground floor?

 

[noseall]

i fear choking the exit may cause draw problems.

throating a chimney helps reduce rain ingress and promotes draw.

throating involves making the air travel around the masonry as opposed to straight up. the channel is narrowed one way and widened the other so it is more of a slit then an open tube.

i read on the link about the inflatable condom method. this involves inflating a long balloon up a flue then filling it with concrete. deflate the balloon and you have a smooth flue. success will depend upon how well the concrete travels down and around the balloon.

 

[Softus]

Sorry - I'm guilty of not giving you all the information.

The grate is no longer used. However, that doesn't mean it never will, therefore the customer wants to prevent heat loss in a way that can be reversed if needs be. Clearly the occupants will all be aware that a fire shouldn't be lit in the grate.

 

[noseall]

oh.

i'm thinking on th lines of an air admittance valve here....

 

[Softus]

I'm not sure I understand how that would be implemented.

Could you expand on your idea?

 

[noseall]

i don't know if it could be implemented.

but if air could be drawn through the chimney intermittently then you are onto a winner.

probably