HELP! Ongoing chemical smell in room above wood burning insert

[emann]

We own and live in a 120yr-old house which is separated into two flats (we live upstairs and have tenants downstairs) and nearly 2 years ago we had Regency wood burning fireplace inserts installed in both units, so that each unit has a functional fireplace and insulated liner. The chimneys are separate but run right next to each other, so the second floor fireplace is almost right above the first floor one.

We LOVE LOVE LOVE our insert, use it all the time, BUT any time there is a fire in the *first* floor insert, we get major chemical smells seeping into our living room from our fireplace. It’s *not* smoke or fire smells, it is a strong chemical smell. (Our CO detector has never alarmed.) We have to open all the windows, and close off the living room from the rest of the house until it dissipates. It is strong enough that it makes us nauseous, sometimes even makes our eyes burn if it really gets going. The chemical smell happens *any* time they make a fire, about 30 minutes into burning, and it tends to get worse from there until we have them let the fire die. It happens whether we are also burning a fire in our fireplace or not. It does not happen more or less dependent on the weather. There is never a time they have made a fire when we have not been able to smell the chemical smell up here. Again, it’s not a Smokey fire smell! It smells like chemicals. Before the inserts and liners, we were building fires in both fireplaces (upstairs and down!) for years and never had any weird (or even smoke) smells or anything like that.

What on earth is happening and how do we make it go away?!? Our chimney/fireplace guys who installed the inserts and liners seem to have no idea what we’re talking about, and have no idea how to solve the problem.

We have been making fires for the past 2 winters, so this is no longer a brand new install. Here are things we/they have *already tried* :
-LOTS OF first floor fires (Assuming perhaps it’s burn off from the newer liner?), letting them burn for long periods at very hot (either when we are out of town/out of the house/or just don’t need to use the living room and can close it off from the rest of our unit)
-stuffing the front of our insert in any places where you can feel a draft (we did not do this ourselves, our fireplace guys did it with special insulation). That helped for a short amount of time (maybe 2-3 fires), but the smell returned after that.
-chimneys cleaned
-raised the cap on the first floor chimney (the chimney caps were already staggered but they lifted it about 2 feet thinking perhaps they weren’t staggered enough and we were getting some sort of down draft from the other chimney in such close proximity)

Any other ideas??? Any idea what’s happening or most importantly how to solve the problem? The only solution I can think of is to not let our tenants use the downstairs fireplace at all/consider it non functional, but we spent thousands on the insert and the liner, that feels like such a sad waste of resources

If you have made it to the end of this post BLESS YOU and thank you so much for helping me problem solve!!

 

[kborndale]

Chemical smell is normally the stove reaching a new high temp.

 

[stoveliker]

Is there an air sealed block off plate in the second floor (your) insert?
If something gets hit because of their flue, and that can get down to your insert, you could smell it.

Are the liners insulated? It sounds like something (plastic?) is getting hot from their liner.

 

[RockyMtnGriz]

Just some thoughts:

Smoke from a modern stove can have a chemical smell once it's up to temperature - which is about 30 minutes in, as you mention, and it doesn't smell anything like a campfire. You might see if you can get downwind of the chimney and see if it smells the same.

Is your insert using an OAK (outdoor air kit)? Could you be pulling air and smell from outside through that or through some outside air leak into the living room?

 

[emann]

Chemical smell is normally the stove reaching a new high temp.

Would this happen in perpetuity though? Forever, or just initially? We’ve had that first floor fire going hot for long periods of time multiple times but it happens even at the beginning of a fire down there.

 

[emann]

Is there an air sealed block off plate in the second floor (your) insert?
If something gets hit because of their flue, and that can get down to your insert, you could smell it.

Are the liners insulated? It sounds like something (plastic?) is getting hot from their liner.

Hmm I’m not sure about an air sealed block off plate, I will definitely ask our installer about this. He has told me the liners are insulated. Thank you for your thoughts!

 

[emann]

Just some thoughts:

Smoke from a modern stove can have a chemical smell once it's up to temperature - which is about 30 minutes in, as you mention, and it doesn't smell anything like a campfire. You might see if you can get downwind of the chimney and see if it smells the same.

Is your insert using an OAK (outdoor air kit)? Could you be pulling air and smell from outside through that or through some outside air leak into the living room?

Ooh I’m not sure about an Outdoor Air Kit, I can ask. Thank you!

 

[jjam]

test the moisture of the wood/ try a differ source of wood / it might be the wood itself / try an open window to do test the next fire

 

[begreen]

We own and live in a 120yr-old house which is separated into two flats (we live upstairs and have tenants downstairs) and nearly 2 years ago we had Regency wood burning fireplace inserts installed in both units, so that each unit has a functional fireplace and insulated liner. The chimneys are separate but run right next to each other, so the second floor fireplace is almost right above the first floor one..

What on earth is happening and how do we make it go away?!? Our chimney/fireplace guys who installed the inserts and liners seem to have no idea what we’re talking about, and have no idea how to solve the problem.

Are both flues terminated at the same height? If so, one may be siphoning smoke into the other. Can you post a picture of the chimney top?

 

[firenightdance]

Holy crap, searched a magic string and this came up. We too get a weird chemical almost "cleaning solution/Glass Plus"-esque smell. We have a brick-covered fireplace with a Jotul mostly tucked into it but part-way outside...and it seems to emanate from the bricks as they get warm with a fire right above the Jotul top. It's annoying. House is from 1984. I'm wondering if prior owner cleaned the fireplace with a cleaner and it got into the mortar. We've had the place for a few years now and just started noticing it this year. I've shoved my nose right up to the Jotel and put my head kinda "inside" the fireplace where the SS liner goes up and I'm 99.9% positive the smell is not in there. It's literally putting my nose up to the bricks. If you leave the room and come back (because of acclimating, sometimes we don't smell it after sitting in here a while) you can smell it in the room. Annoying! Any ideas?

I can't imagine trying to relay what's going on to any local fireplace people. I can already see the blank stares.

It's not as annoying as OP, I have a sensitive nose and it bothers me more theoretically ("Is this bad for us?") than actually. No nausea or stinging eyes. Not yet, anyway.

 

[FireplaceNeedHelp]

I have a similar problem. I live in a condo with a prefab wood fireplace. All neighbors do and they have no issue with burning fires all winter, but when I put a fire on - after some 30 minutes or so, when the fire is nice and burning, I get this chemical / toxic smell which means I'd have to open the windows, and leave the room. I brought countless fireplace companies - had the chimney checked (all clean), and the prefab walls dismantled and properly cleaned. Nothing. When I put a duraflame log, it's different - hardly any smell (or very faint), but i don't count that as a real fire. I also tried so many different wood - making sure it's not from the wood. Anyone with a similar problem? I bought my condo mainly for the fireplace, as i found it would make so cozy. And here I am!

 

[UpNorth30]

The best way forward is to terminate their wood insert and get them a gas or electric or neither. The low probability that you will ever solve it perfectly. The potential cost to truly identify the root cause. The potential cost to then fix the root cause if found. Makes this issue a clear wave the white flag and surrender. Especially because nearly all tenants never expect wood stoves nor pay a premium to justify your hassle.

You could always do tests if you are stubborn and want to keep punishing yourself.

1. You or someone hired goes on your roof and smells their smoke when burning to ensure that the chemical smell is not at all alike to the smoke. This will rule out smoke. Also, getting a plug-in CO detector that has a digital display showing the detection limit may help prove it is not a combustion product you smell. Those will show increasing CO above zero but not alarm until dangerous to humans.
2. Use painters plastic and painters tape to seal off your fireplace perfectly so it cannot possibly share air with the room. Tape the entire perimeter of the plastic tight to the walls, ceiling and flooring adjacent to your hearth. Just like you are working in a biohazard lab and want to keep the virus out. Maybe go out a few feet in all directions from all of it ( your hearth, brick, chimney) for good measure. Then have them fire up the lower insert. This will ID if the intrusion is through your insert/hearth area or somewhere else in the room. If you do not get a chemical smell then you know it was from your insert area and then plastic off ever smaller portions of your insert/hearth until you locate a small area of intrusion.
   1. Version 2. If you get chemicals still while your entire 2nd floor fire area is sealed then leave it sealed and seal the entire floor of the room just above the mop boards, corner to corner, taped to the floor at all the entrances to the room. This will ID if it is coming thru the floor.
   2. Version 3 If you still get chemicals with hearth and entire floor sealed then start doing potions of walls or individual windows. Etc
   3. Obviously all of the above require a cool down, and re-light as each new test is conducted.
3. You can hire a lab with chemical air testers to determine the nature of the chemical. Is it formaldehyde based, benzene based, other? This may identify the off gassing part of your home.

My gut feeling is that this is off gassing of hot materials that make up the building. Do you have wood floors? Typically 1920s homes had wood floors built on sleepers. Look it up. The gaps between the sleepers where often filled with sawdust or sand or whatever for sound dampening. If that gets hot there may be off gassing. Maybe there is modern underlayment under newer wood floors that is synthetic and gasses when hot. The plaster often had horsehair as a filler, maybe the hot lathe and plaster is off gassing. Old paints or varnishes that are getting hot in-between floors or in the chimney wall. Chicago style brick and cinderblock is porous and will absorb whatever cleaner or paint or varnish go onto it.

To test if the normal walls or floor/ceiling is off gassing you could light their fire and then take great measures to keep the walls and ceiling normal temp. You could build some apparatus between the top of their insert and their ceiling to kick the heat outwards only. Space blankets and whatnot. With all their windows open in their fireplace room on a cold day. If you are sure that the ceiling and immediate walls by their insert are not warmed or hot, and the chemical smell persists, then you know it is materials in or on the chimney itself and not walls or floors or subfloors off gassing.