Smoke out of open fireplace

[KevinM]

Occasionally I get smoke spilling out of my fireplace when I am reloading. I have glass doors, which stops it when the fire is burning. The draft is noticeably poorer when it is warm, ie getting close to above freezing. I live in a bungalow so the chimney is not that tall. I crack the door open slowly and let the airflow build, and the fire has been going so the chimney is warmed up.

Two ideas for solving the problem:

A) My neighbour recommended putting firebricks under the grate to raise it up

B) Improve the draft proofing of the house especially for areas above the opening of the fireplace. My main concern is the windows; most of them are horizontally sliding glass with a trim on only the two sides. The trim in the centre comes loose/bends and the two panes do not seal very well anymore.

Do either of these sound useful or is there anything else I can do? I do plan to get an insert this spring/summer. If this continues with the insert in place I will be in hot water since it irritates my wife’s throat.

Kevin.

 

[myzamboni]

I had this problem whan I had a ZC fireplace. You need a longer chimney. I added 3 ft in height and the smoke issue went away.

 

[gpcollen1]

A leaky house should not impair your draft - the short chimney might. Do you have the damper open all the way? On my fireplace, I try and not leave the damper full open as it sucks a ton of air through it. I close it one click as soon as the fire is roaring. If I close it 2 clicks, I get some smoke spillage back in the room sometimes - though i can close the glass doors with it this way - like I do when I go to bed.

 

[webbie]

Extending the chimney - or dropping the fireplace opening a couple inches. There is a unit called a smokeguard that might help you drop the fireplace height on a temp basis.

Raising the floor of the fireplace a few inches (the whole way across) might help a little.

 

[KevinM]

The damper has five settings: 1 is wide open, 2 is around half close, 3 is open a crack, 4 and 5 are fully closed. I usually leave it wide open (1) but when it gets cold I can close it down to 2. If the fire is burnt down to coals I will leave it at 3 when I go to bed.

I think the clay flue tile is 8x12" if that makes any difference. I will measure the opening size tonight. What is the ratio of the sizes supposed to be?

I figured any extra space under the grate would get filled up with ash ;-). I don't know if the idea was height or effectively reducing the fireplace opening size. Either way sounds easier to build up than down.

Kevin.

 

[webbie]

I don't know if the idea was height or effectively reducing the fireplace opening size. Either way sounds easier to build up than down.

Kevin.

Mostly reducing the fireplace size.

 

[Mo Heat]

A dirty chimney can reduce draft and cause smoke spillage. So can a leaky chimney that is "spoiling" your draft by sucking air in above the fireplace opening, if say, some of your tiles are broken, cracked badly, or the mortar between tiles has come loose.

When's the last time your chimney was cleaned and inspected?

 

[jtp10181]

Get an insert and I bet your problem will go away.

Also there are quite a few things to consider for the current problem.

Wood Quality - wood with too much moisture will create lower stack temps and you will never get a good draft. If you have a hard time getting the fire going or keeping it going the wood is wet. If the wood sizzles or has bubbles coming out of the ends it is too wet.

Stack Effect - You want the house tight on the top and loose on the bottom. If the house construction is loose on the top the house can make a better chimney than the chimney itself. Can lights, attic stairs, etc... Any penetrations in the top of the house can result in leaks up there.

Stack Size - an over-sized flue will result in poor draft. Installing an insert you will want to do a full 6" liner to the top, this will resize the flue and you will get optimal drafting.

There's a lot more but I can't think of them right now, those 3 are the big ones that stick out in my mind. Wood Quality is what I usually encounter with my customers.

 

[KevinM]

A dirty chimney can reduce draft and cause smoke spillage. So can a leaky chimney that is "spoiling" your draft by sucking air in above the fireplace opening, if say, some of your tiles are broken, cracked badly, or the mortar between tiles has come loose.

When's the last time your chimney was cleaned and inspected?

It was inspected and cleaned three years ago. We only burn one or two face cords a year. Took a picture up the flue and nothing looks broken. Should take a look from the top but it is feezing cold, icy and dark on the roof when I get home from work.

Second picture I am a bit concerned about missing mortar at the bottom of the tile lining, any comments.

Kevin.

 

[KevinM]

Get an insert and I bet your problem will go away.

Also there are quite a few things to consider for the current problem.

Wood Quality - wood with too much moisture will create lower stack temps and you will never get a good draft. If you have a hard time getting the fire going or keeping it going the wood is wet. If the wood sizzles or has bubbles coming out of the ends it is too wet.

Stack Effect - You want the house tight on the top and loose on the bottom. If the house construction is loose on the top the house can make a better chimney than the chimney itself. Can lights, attic stairs, etc... Any penetrations in the top of the house can result in leaks up there.

Stack Size - an over-sized flue will result in poor draft. Installing an insert you will want to do a full 6" liner to the top, this will resize the flue and you will get optimal drafting.

There's a lot more but I can't think of them right now, those 3 are the big ones that stick out in my mind. Wood Quality is what I usually encounter with my customers.

How important is the stack effect with the fireplace on the main level of a bungalow? Most rooms have a single ceiling light which isn't sealed in the attic. The windows do leak at the top as shown in the picture. The white trims should be straight and interlock making a good seal, they curve outward and don't. I have tried pushing them back straight but as soon as the window is opened and closed they are curved again. They are stuck in the middle so completely removing to straighten isn't an option. I could try painters tape on them and see if helps but won't be able to keep the tape up for long.

Wood quality isn't great but dry indoor air and loose stacking in a semi finished area of the basement has helped allot. Can't really do anything about stack size for the fireplace but Canadian code calls for full lining for the insert.

Kevin.

 

[RonB]

Stack Size - an over-sized flue will result in poor draft. Installing an insert you will want to do a full 6" liner to the top, this will resize the flue and you will get optimal drafting.

JTP,
Sounds like good advice if he owned a stove or insert. Are you sure his masonry fireplace with glass doors would draft properly on that 6" liner?

 

[jtp10181]

Stack Size - an over-sized flue will result in poor draft. Installing an insert you will want to do a full 6" liner to the top, this will resize the flue and you will get optimal drafting.

JTP,
Sounds like good advice if he owned a stove or insert. Are you sure his masonry fireplace with glass doors would draft properly on that 6" liner?

I wasn't suggesting to re-line it to 6" with the masonry unit, only if he got an insert. But it is still possible to have an over sized flue with the masonry unit.

 

[RonB]

Stack Size - an over-sized flue will result in poor draft. Installing an insert you will want to do a full 6" liner to the top, this will resize the flue and you will get optimal drafting.

JTP,
Sounds like good advice if he owned a stove or insert. Are you sure his masonry fireplace with glass doors would draft properly on that 6" liner?

I wasn't suggesting to re-line it to 6" with the masonry unit, only if he got an insert. But it is still possible to have an over sized flue with the masonry unit.

I misread your original post JTP, I didn't see the part about the insert. Thanks.

 

[jtp10181]

You are probably getting smoke back from a combination of weak draft due to a short flue combined with unseasoned wood worsening the situation. The air leaks up top I doubt help the issue.

 

[Mo Heat]

It's hard to say about the stack effect, but clay tiles warm up real slow and loose heat fast, so if your chimney is on an exterior wall and it's not real sunny outside (or even if it is sometimes), the wind blows over a roof or trees and down toward the chimney, or even a dirty rain cap, then you can have draft problems.

If it was me, I wouldn't even bother burning that fireplace if you are doing it for heat (unless that's your only heat source). I've had fireplace glass doors and I know they put out almost NO heat when compared to an efficient insert. Your best bet is to get something in that fireplace that was meant to produce heat. IMO, a masonry fireplace and chimney isn't much good for anything but looking nice, at least when you compare it to the enormous heat differential you'd be getting from an efficient insert.

 

[KevinM]

I finally found some 2.5 inch firebricks yesterday to try under the fire grate. At only $1.50 each they were cheaper than Rona wanted for the 1.25 firebricks.

They were stored outside and had ice on them. How long do you think they need to dry out before using? Should I take it easy on them the first few fires or can I just lit it rip?

Kevin.