Smoking fireplaces part 4: smokes on windy days
It is one of the most valued features in our homes. And all too often, the fireplace is labeled "non-working" and sits unused, because the homeowner doesn't know what to do about a smoking problem. Here I will show how most smoking problems can be handled relatively easily, with little or no expense. We'll cover:
Here's a trick for monitoring smoky fireplaces: If you can't see the smoke spilling from the fireplace, shine a flashlight across the fireplace opening. The light reflecting off the smoke particles will make it easy to see.
Fireplace smokes on windy days
Chimney is Too Short: Wind patterns around a house create pressure zones against the roof. Wind-driven pressure zones are a complicated science, but basically, if the chimney is not tall enough, a pressure zone created by wind will engulf the chimney top, forcing wind-driven smoke down the flue and into the house.
This is why current building standards require a minimum chimney height of three feet above the roof penetration, and two feet higher than anything within ten feet of the chimney. If your chimney doesn't meet this standard, have a professional add height to it.
Sometimes, although the chimney is tall enough compared to the roof, its overall height isn't adequate to overcome a driving wind. Especially for short chimneys in one-story homes, adding height above the required minimum is a good idea if wind is a problem. Ask your chimney professional for advice.
No Chimney Cap: A chimney is an open cavity leading into your home. As such, all chimneys should have caps. A good chimney cap, constructed of stainless steel, copper, masonry, stone, etc, will not only prevent rain and snow from entering the flue, but will also help with certain wind-driven draft problems. The science of pressure differentials is fodder for physicists. Suffice it to say that a good cap, properly installed, helps keep the wind from blowing down the chimney.