Possible negative pressure problem?

[mjcobucci]

I am a first time home owner AND a first time fireplace owner. My typical NJ Bi-level style home has a masonry fireplace on the first floor. I have a spring loaded, gasket sealed top damper installed, which claims to be airtight and I do not see any sunlight coming through when it is closed. I have overlay style glass doors on the front of the opening, which are not airtight. Since moving in I have attempted to burn 2 "fires" (using a small 2 pound duraflame log, dont laugh!). The situation I am experiencing is that after the fire has gone out and I have waited for the afterburn "coals" to have died out and cooled off, I proceed to clean up the "ashes" and dispose of them. Then I proceed to close the damper, approx an hour after my little fire has gone out. About 30 mins after I close the damper and the glass doors the entire first floor smells like smoke. 30 mins later the enitre second floor smells as well. The smell seems to first encompass the fireplace room, them proceeds to the hallway and up the stairs to the second floor and then to the back of the second floor hallway where it so happens that the attic door is located on the ceiling. It is important to note that when i re-open the damper the smell seems to lessen significantly.

I have read through many many posts on this site and my best guess is that I have a "negative pressure airflow" problem, possible caused by a drafty attic. I hesitate to mention this guess since i don't want to influence any solutions you may post.

Please help. Thanks in advance to your assistance.

 

[Chettt]

Do you have a forced air furnace that may be coming on and pulling air through it's return? That and clothes driers pull with a lot of negative pressure.

 

[gzecc]

Virgin, I am a neighbor in Bedminster. I would leave the ashes for 24hrs first. Try that and see the results. Unfortunately fireplaces are extremely inefficient. Usually they pull the room air out. Variable conditions always exist to allow otherwise.

 

[mjcobucci]

Chettt, yes I have both but neither were on at the time, the spread of the smell happened in a relatively short period of time as well...

gzecc, what effect does leaving the ashes have? at this point ill take having the fireplace suck air OUT, but it seems like the opposite is happening, didnt think that was possible with an airtight damper though...

 

[Hurricane]

Welcome,

You say the ashes are cooled off, is the masonry fireplace cooled off ? I am not sure what the effect would be if you capped a hot chimney.
Try leaving the cap open until the masonry in the fireplace is cold. You can try different amount of times taking into account outside temp and how hot/long you have been burning, the masonry will hold heat for a long while.
I think as the warm or hot air in the chimney cools it will drop down to the house replaced by warmer air from the house.

 

[gzecc]

Virgin, My idea is to have the masonary fireplace/ chimney cool down completely. I would assume your top cap is not as air tight as you may think. Is there an ash cleanout in the basement or outside?

 

[mjcobucci]

The ash dump clean out door is outside. It is an external chimney.

 

[ansehnlich1]

Well, cold air falls, and warm air rises. I think you have your little fire, and when finished you close things up, and then the air in the cold chimney, which smells like chimney ;-) drops down and flows into the living room. You see, brick/stone/clay have an amazing ability to hold this kind of nasty smoky creosotey smell in them and when that air reverses my guess is THAT smell goes with it.

Now, you likely are correct in that the entire house may be acting as a chimney, and that attic door may be a culprit. My guess is that is the case, warm air rises, if you have a drafty window or attic door in the upper level of the home, logic would dictate that the lower level warmer air would rise to the upper level.

 

[LLigetfa]

Even if the top damper sealed well, there is enough air in the flue to create a downdraft as it cools. There could also be small leaks in the masonry and need repointing.

You need to find and seal all the leaks where warm air is escaping. If your attic has whirly bird vents, make sure there is sufficient soffit vent to supply them.

 

[mjcobucci]

What is a whirly bird vent? How can I tell if I have sufficent soffit vent?

 

[LLigetfa]

Measure the width and multiply it by the length and you will have the area.

(broken link removed)

 

[ansehnlich1]

What is a whirly bird vent? How can I tell if I have sufficent soffit vent?

Methinks my friend is referring to a spinning vent that would be on your roof somewhere, or at the peak of your roof, and also, to the soffit, which would be under the eaves of your roof. The soffit would have little holes punched all throughout, or possibly 2 inch diameter holes pr some such interspaced along there, to allow air flow into the attic area of your home.

BUT<

I think your first move should be to have your chimney cleaned/inspected by a professional sweep, if you have not had that done yet.

NEXT, I'd seal that attic door opening, either with a "battic door" which you can google, or some such item, or simply tape the seam around that door for now with some painters masking tape and see if that makes a difference.

Also, try to seal up any other obvious spots where air may be entering/exiting the home, especially on that second floor.

 

[mjcobucci]

I've had the chimney cleaned twice, once when i had the previous owner's 20 year old peice of rusted garbage insert removed and then a second time when I had the top damper installed.

I definitley dont have that kind of vent on the roof. I have an electric temp controled attic fan with 2 slotted wall vents, 1 on each end of my rectangular shaped house. The attic fan and the vents are permanently open. Are they supposed to be?

I just ordered the battic door and im going to try the painters tape as a temp fix! Thanks

 

[ansehnlich1]

I've had the chimney cleaned twice, once when i had the previous owner's 20 year old peice of rusted garbage insert removed and then a second time when I had the top damper installed.

I definitley dont have that kind of vent on the roof. I have an electric temp controled attic fan with 2 slotted wall vents, 1 on each end of my rectangular shaped house. The attic fan and the vents are permanently open. Are they supposed to be?

I just ordered the battic door and im going to try the painters tape as a temp fix! Thanks

Well yes indeed, if you have an attic fan, which is designed to duct air OUT of the living area of your home and INTO the attic, then yes, you will want to have that fan turned off, and seal any area where you could have air escaping from the living area of your home into the attic, or outside the house. You see, this creates a draft where your home becomes a chimney all by itself, and could very well possibly being drawing air down your chimney and then through you home, up the steps, and out through any opening you have into the attic.

Sometimes running simple kitchen exhaust fans, or clothes dryers, can do the same thing, as they both need to suck air from somewhere, and at times that air comes from an already cold outside chimney.

Good luck and let us know how you make out.

 

[Hurricane]

Most attic fans are thermostatically controlled and would not be running when it is cold outside. I think the slotted wall vents aka gable vents are fine too. I think you need to try letting the fireplace more time to cool down before closing the damper. Try waiting until the morning.