Rigid pipe as a flue liner?

[Etoile]

Any help would be appreciated. I am about to install a second hand woodburner in an old stone fireplace. Being shocked at the price of flexible stainless steel liners I am wondering if there is a less expensive option in using some form of rigid pipe, considering that my chimney is dead straight up and I can see the sky from the fire place, 8 metres up. Maybe I can even feed this up from below in telescopic sections?

Whilst on the subject my burner has an outlet of 20cm diameter but I believe I may be OK with something about 15cm wide? I think that is about the width of the existing chimney towards the top.

Thanks in advance for any views on this.

[dave21478]

All the diy shops sell lengths of chimney conduit in rigid sections. Last one I fitted was the same situation as yours, so I just fed the sections in one at a time in the firplace untill it reached the top, then connected to the burner with a bracket around the lowest section to hold some of the weight.

It should be noted that what appeared to me to be the logical way to assemble them - Narrow section upwards so the rising gas can not escape through the joins - is actually the wrong way to do it, as the condensation and soot can trickle down inside the chimney and escape through the joints and run down the outside, making a hellish mess. Make sure you assemble them with the narrow section to the bottom.

[Etoile]

Thanks Dave, just the sort of reply I've been dreaming of! I really cannot see why I need to go to the expense of the flexible liner when my chimney is straight. The only thing I might do in addition is fit a top plate to keep the heat in the chimney and the weather out.

Thanks for the tip about the correct positioning of the pipes: I have read this male down female up thing before and it certainly makes sense, although it does go against ones immediate instincts.

[NickP]

I'm not being negative but please check with your insurance company or the makers of your stove, because although you say it's not a new wood burner the heat generated by modern stoves in the chimney is tremendous, and it's not just about flexible tubes, it's to do with the capacity for dealing with extremely high temperatures. Also make sure the chimney is cleaned thoroughly before fitting a liner.