Replies

1. 
   Guest_ | Nov 11, 1999 09:35pm | #1

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   Sounds like wind is pressurizing the chimney, or perhaps depressurizing the house, assuming the fireplace is otherwise set up correctly. I've seen special hoods used in a seaside community that actually turn with the wind, I assumed to keep the chimney exhaust downwind to maintain proper draft. Note also how the chimney is situated relative to the roofline -- wind flowing over and around the roof could be hitting the 2d chimney quite differently from the first.

   Sounds like a job for a fireplace expert. I do know for sure, no 'e' in smoky. :)

1. 
   Guest_ | Nov 12, 1999 04:19pm | #2

   *Andrew,My thoughts exactly. You might try putting a partial block on the cap and move it around to different places. It may also involve raising the cimney a couple of feet (last resort). Do you have good airflow inside? Is there a return air duct in the same room with the fireplace. First thing to try is to cut off hvac and light a fire with a window cracked. If this works then you need to install fresh air vents to the fireplace. This is a common problem/cure in new houses. Worst case senario, fireplace was constructed improperly and will have to be rebuilt or modified.Rick Tuk

1. 
   Guest_ | Nov 12, 1999 07:28pm | #3

   *Casey - I remember something from my youth about the top of the chimney having to be a certain height above the ridge(?) of the roof plane it comes through, or the swirl of air as it gets deflected by that roof plane will cause the problem you describe.

1. 
   Guest_ | Nov 12, 1999 11:19pm | #4

   *A chimney should extend at least two feet above the roof peak or above any portion of the roof within 10 feet of the chimney.If this is a one story chimney next to a two story house, this can be the cause of your problems.Too large a chimney can also be a problem. If you can't heat all of the air in the chimney, won't draw correctly.In addition, wind flowing over roofs, trees, and other objects can cause wind to blow right down a chimney.Smoking fireplaces and ceiling leaks. The two most difficult things to diagnose and fix.

2. 
   Gary_R | Nov 13, 1999 03:30am | #5

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   Thanks to all for your input on my fireplace problem. I just started using this forum and the repsonses to my questions have been freindly and professional. All comments/suggestions are very much appreciated and are all taken into consideration. Thanks again gentlemen.

   Gary

3. 
   Guest_ | Nov 13, 1999 06:41am | #6

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   Gary,

   Another possibility: is the chimney which smokes an exterior chimney? They tend to be much cooler than interior chimneys and are much more likely to downdraft because the cooling effect on the flue gases, limits the upward force of the heated gases.

   Everything I've read and experienced suggests that fireplace and chimney construction is as much witchcraft as science

   A good chimeny mason (or _very_ good chimney sweep might be able to help diagnose the problem and help craft the solution.

   Bob

1. 
   Guest_ | Nov 13, 1999 07:32am | #7

   *Does the chimney have a smoke shelf in it? These are supposed to keep downdrafts from pushing smoke into the room. You may also have very tight construction in the addition. Maybe raising a window slightly will help. My house is built so tightly I have to turn my furnace off when using my fireplace as it sucks the smoke back through the chimney. Raising a window helps me with this.

4. 
   Terrence_N._Banbury_NCARB | Nov 19, 1999 02:40am | #8

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   All very good posts! If it just occurs when it is windy and the flue/chimney has warmed, then my guess would be some kind of interference from adjacent roofline (possibly 2nd story?)as opposed to the smoke shelf.

5. 
   Guest_ | Nov 19, 1999 04:34pm | #9

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   Brian,

   Try having some fresh air vents installed in the fireplace or right next to it. There are vents made for this purpose. That way the fireplace doesnt pull cold air across the room.

   Rick Tuk

6. 
   Gary_R | Nov 19, 1999 07:37pm | #10

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   All of the suggestions are great and I intend to systematically check them out. For all who are interested in this problem I found out another possible cause on http://www.firelogs.com/HyC.htm in the FAQ section. Apparently the opening of the fireplace should not be any larger than ten times the opening of the flue. My fireplace is 37x26 which equals a 962 square inch opening. I have not measured the flue opening, but according to this formula it should be at least one tenth of this number which would be 96.2 square inches. Thanks again for all your help.
   Gary

7. 
   Gary_R | Jan 04, 2000 11:36pm | #11

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   There are two fireplaces in my home. The original is about 70 years old and the chimney extends from the main floor and on through the second floor to the roof. I have no complaints with this one, it has a great draw and smoke never enters the room. Burns Beautifully. The problem is with the other fireplace that was built with a one story addition.(previous owners). I noticed that when it is windy smoke is forced back down the chimney and into the room. I mentioned the other fireplace because its chimney is much longer which I thought was why it was not affected by the wind. Presently there is a cap on both chimneys to prevent rain and animals from entering. I need help on this one.