Efflorescence or filler???

23-04-2023 8:58pm #1

Hi guys

Wondering if anyone can tell me is this efflorescence on the chimney linked below in the cracks?

Background is had a wood burning stove fitted awhile back, there was a chemical smell coming from it (not like paint curing and long after it would have been cured)

Fitters came out to check, can't find an issue with the fire and have come back saying that there's silicone/filler in cracks on the chimney, after a while when the chimney heats up, they said the silicone/filler is melting, and the smell is coming back down the chimney between the liner and the flue, and into the house from there/the surround.

I got up to take a look myself, and aside from the fact I now know there's cracks and I'm going to have to get it re-rendered, all the white lines ect seem more chalky so to speak, not like silicone. Basically I'm trying to figure out if I'm being fobbed off, and wondering if this is efflorescence or could it actually be plausible that it's a form of filler there many years is whats smelling.

Incedently marks are right around chimney and on neighbours side too, they've never had a smell from their fire or stove

Any ideas appreciated

Doop · 24-04-2023 10:39am

I would say its probably unlikely to be efflorescence due to the age (by the looks of it) of the chimney/property. what age is it?

The silcone story sounds like a fob alright ...in my opinion anyway. It really doesn't look like silicone and it would never have been the correct product for someone to use in that instance.

The Continental Op · 24-04-2023 10:47am

OP what are the pipes coming out of the chimney?

btw try burning some silicon sealer from a tube in your stove and see what it smells like?

24-04-2023 11:49am

Its built early 50s so should be there 70 years now. There was an open fire used prior to the stove, but never any smell when that was used.

The pipes are 2 copper vents or hockey sticks either side of the liner. The installers originally put them in when I had complained of a smell.

At first they thought it may have been the vermiculite that backfilled the flue, they removed that then put in the above sticks, the smell was still there so they thought it was coming from the granite edging on the fireplace (it's a cassette stove) they removed this and said that wrong adhesive may have been used on it. This somewhat seemed to solve the problem untill recently, the fire was lit for a few hours and the smell came back.

When I called them to let them know they are saying they think silicone/filler is used in the cracks in the picture, after a few hours burning when the top of the chimney gets hot, said silicone/filler is melting and producing the smell that is coming back down the chimney between the flue and liner and into the house.

I've only ever burned kiln dried logs so definitely not related to the material I'm burning, smell is like a chemical smell, I'd asked about replacing the actual fire box of the stove, but they seem to think it can't be related as it's a metal box with nothing to melt, so back to the theory it's coming from outside.

The Continental Op · 24-04-2023 12:10pm

Really doubt its anything in the chimney. Smells go out and up the chimney. Something is heating up down around the stove and smelling. Has the stove been out since it was installed? It could be something that went in when the stove was installed.

10-10-20 · 24-04-2023 12:46pm

Did you inspect/photo the cap of the chimney at all? Any indication of deterioration there?

I'm wondering if they used lime in the brick mortar, that might leach out and present lines such as that.

24-04-2023 1:26pm

https://www.boards.ie/discussion/comment/120514859#Comment_120514859

They had it out to take out the vermiculite beads then put it back in. I noticed there's still rockwool in around the stove and mentioned it, although they said the fire wouldn't get hot enough to burn any of that. They said fire cement was used to attach the liner to the box and wouldn't be that either.

Looking around the area there's a lot of other chimneys looking the same as mine, white lines/cracks, so must be something in the mix when they were originally rendered, as I doubt someone went around all the houses with a gun of the same gunk. They are saying they have never seen or heard of a similar problem before though

The Continental Op · 24-04-2023 1:37pm

Get some rockwool put it in an old tin can and put the lot in the middle of a hot fire. Open it up after a while and see if its the same smell.

Something is creating a smell it is likely on the stove, around the stove or even directly above the stove. Anything above the stove on the chimney breast that gets a bit warm when the stove is running? I've had paint smell on a mantle piece when a fire got too hot but my fault as the mantle was too close to the top of the fire.

Which reminds me there was a brand of emulsion paint that was withdrawn because of the smell wonder if you have something that just smells when its warmed up.

24-04-2023 1:51pm

Here's the chimney from above

https://tinypic.host/i/oAM11h

I'll try the rockwool suggestion and see, it's a distinctive smell I'd know it straight away.

There's no mantle above it or anything only a mirror higher up the breast but it doesn't get hot really where its at.

I've actually painted it 2 different colours and brands since but smell was there for both, one other theory I had was it possible adhesive left on the plaster from the previous fireplace surround/mantle, that was plastered over when the new fire went in and is smouldering through when it gets up to temp, I'll try the suggestions above though

Efflorescence or filler???

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