woodburning stove?

Hi Mark, you're right you need to create a seal between the flue pipe and the stove. You should do this using fire cement which will create an air tight seal around the flue preventing harmful gases escaping. A small tub of fire cement costs a few pound and will be sufficient for your clearview, see the link below:

http://www.thegreenercompany.com/heatproof-products/324-kos-black-fire-cement-500g-stoves-a-fireplace-care.html

David
April 2010