Chimney Lining Problem

[robritchie]

Thermocrete lining to end terrace house - installed November 2010 ( 25 year guarantee)

First winter (2010/11) - chimney used without trouble

Second winter (2011/12) - used on a number of occasions - day after significant smoke leak into the attic at top of house. Does not seem to happen until day after. No leak into rooms under attic but visible smoke in attic.

Have had company back to do CCTV - apparently lining intact but smoke leak continues. Currently fire not useable as smoke is a health risk. Lining cost £2k so would like a solution.

Does anyone have any suggestions? There are 5 flues in total in the house; only one has been lined but this the only flue that we use. All the others are sealed over.

Thanks in advance.

 

[Boilerman2]

Why not ask the Installer for advice he has the advantage that he has seen the site
we have not!

 

[robritchie]

Why not ask the Installer for advice he has the advantage that he has seen the site
we have not!

Thanks for that thought. I have spoken with the installers on numerous occasions and as I said in my post - I had them back out to do a CCTV inspection recently. Unfortunately they are not sure what the problem is, hence my asking for advice on this forum.

 

[simond]

You do not say why you had the thermocrete lining put in, and what you have at the other end.

I suspect it is not a boiler but a fuel burning stove.

If My assumption is correct, and the CCTV/smoke test shows it is complete and continuous, then i suspect the high flue temps are setting fire to some adjacent combustible material in the loft. Such as joist ends/framing around the exterior of the chimney stack.

 

[robritchie]

You do not say why you had the thermocrete lining put in, and what you have at the other end.

I suspect it is not a boiler but a fuel burning stove.

If My assumption is correct, and the CCTV/smoke test shows it is complete and continuous, then i suspect the high flue temps are setting fire to some adjacent combustible material in the loft. Such as joist ends/framing around the exterior of the chimney stack.

Hi. The thermocrete lining was installed because the open fire (installed at the other end) was leaking smoke into the top bedroom. We have a CCTV test which showed that the original lining from when the house was built had corroded so a new thermocrete lining was installed.

In response to your point, if the lining is complete all the way to the top of the chimney stack then how would items in the loft catch fire? I'm not an expert so value your thoughts.

 

[simond]

The liner is designed to form a gas tight seal, it does not perform as an insulator. Thermacrete is probably better as an insulator, but unlike a metal liner, this is laid straight onto the chimey walls leaving no air gap.

On ropey builds, it is not uncommon to find ends of joists protruding into the annulus of the chimney.

Depending on the type of fire, and the resultant flue temperatures, you could be smouldering combustible dry material in the loft.

Failing this, you have a crack in the coating - which your post suggests is not the case.

There is an outside chance that if you chimney stack has been topped, (reduced in height) the products of combustion may not be clearing and are coming in under the roof tiles.

 

[xr4x4]

There is an outside chance that if you chimney stack has been topped, (reduced in height) the products of combustion may not be clearing and are coming in under the roof tiles.

This is what I was thinking, how high is the stack?

Got a pic? Have you looked at the stack outside when the fire?? Is lit.

 

[jono_h]

Can you find someone with a smoke generator of some sort to test the stack?

If its a damaged lining, or a stack height issue the problem will still occur, if it's due to heat / combustible materials then it shouldn't occur.