Lining a chimney with an oil fired boiler?

[stats696]

We have a Worcester Danesmoor 18/25 boiler in the kitchen leading through a white enamel pipe to an unlined 9" clay chimney. We live in a bungalow and over the last couple of years (Since we removed the open fire and replaced it with a gas fire) have had problems with water ingress causing the plaster on the chimney to produce a salting effect and bubble in places. I have recently paid our builder to demolish the chimney stack to below roof height and rebuild replacing the lead flashing to stop the water ingress. He has noticed that the soot in the chimney seems to be damp and on investigation when the boiler fires up, after a couple of minutes there is water being produced from where the enamel pipe meets the wall. My plumber has said that the water ingress is two fold, one from the water into the chimney stack from the previously defective flashing and two, condensation from "cold stack" since the vapor from the boiler cannot escape the chimney before condensing causing water, and the best way to remedy this is to line the chimney and back fill with Vermiculite. He has quoted £795+VAT for doing this, this seems excessive as, when the other side of the chimney was lined for the gas fire it cost only a couple of hundred pounds including vat. Is this a job that I could do myself as it looks fairly straight forward?

 

[Agile]

The usual way to deal with this is with a stainless steel liner which is usually about £300 installed.

That would probably solve the problem but the remaining space could be filled with loose insulating material but few bother with that.

Its essential to get the right size liner and the manufacturer of the boiler will advise.

Anything to do with flueing should be done/specified and supervised by a boiler engineer.

Tony