Improving Chimney Safety, Performance & Efficiency Since 1979

Frequently Asked Questions

Q) It looks like my fireplace and furnace both go into the same chimney. Are they connected?
A) They shouldn’t be. Chimneys built in the last 50 years or so are required by the building codes to have separate flue liners (usually clay tiles) for each fireplace and heating appliance. In older homes, there may or may not be completely separate flues, and the flues won’t be lined.

Q) My fireplace smokes. Why does that happen.
A) Many different problems can cause a fireplace to smoke. Some fireplaces were either not designed or constructed properly to begin with and consequently smoke. Other fireplaces may have an intermittent problem created by wind, barometric pressure, temperature outside or negative generated inside the house due to fans, vents and the stack effect.. Still other smoking problems are caused by deteriorated chimneys, rusted dampers, or birds/animals. Every problem has a solution The trick is differentially diagnosing the problem correctly.

Q) Why doesn’t my damper close properly?
A) Cast Iron Dampers can be rusted or warped, or may have a faulty mechanism for closing the damper. Soot, debris and critters are often wedged behind the damper?

Q) What is causing the stains on the outside of my chimney?
A) Black stains may be caused by extreme soot buildup. Brown stains may be from a rusty chimney cap, chase cover or flashing. White stains are probably salt leeching out of the brick due to a water problem.

Q) Why is my chimney leaking?
A) There are five common sources of water leakage in chimneys.: 1) No chimney cap or one that is undersized. 2) A cracked or broken crown (the layer of mortar or concrete covering the top course of bricks). 3) Porous brick allowing water to be drawn into the chimney. 4) Defective flashing (seal between the chimney and the roof or sidewall. 5) Condensed water vapor from gas or oil fired heating systems.

Q) I clean my woodstove chimney every year and yet just had a chimney fire. How could that happen?
A) There are types of creosote and tar buildups that can’t be removed by wire brushes. Chimneys on located on outside walls, some chimney designs and certain stoves will have this problem. Some chimney professionals use rotary power cleaning equipment that are aggressive enough to remove this type of buildup. You may need to have the stove installation modified for safety reasons.

Q) I get a headache or nauseous whenever I am in the basement for a while. Could this be a chimney problem?
A) These are tow common symptoms of Carbon Monoxide poisoning. Have your boiler and/or chimney checked immediately.

Q) I hear noised inside my chimney. Is my chimney possessed?
A) Maybe……but it’s more likely there is a critter inside or on top of your chimney. Birds or squirrels will can’t get out and will eventually die. Raccoons can come and leave at will, but may be establishing permanent residence or possibly having babies. You might also be hearing the wind or tree branches rubbing against the chimney.

Q) The technician servicing my furnace mentioned that the chimney looked dirty and should be cleaned. Aren’t they supposed to take care of that?
A) Most technicians are not trained to do anything with the chimney flue. Consider yourself lucky that he/she made not of the problem and mentioned it to you. The pipe from the furnace could be partially or totally blocked by fallen debris and there could be enough buildup in the flue to obstruct the draft. Both these problems can cause safety and furnace performance issues.

Q) Why did my furnace technician say there appears to be a problem with the clay tile liner? I though they last forever.
A) Chimney liners can deteriorate for various reasons. If you burn oil, the soot deposited in the flue contains Sulfur compounds. The sulfuric acid creaded when this buildup reacts with water or water vapor, can rot out the flue over time. Gas furnaces and hot water heaters have flue gases that contain corrosive compounds and high quantities of water vapor. Once again, many liners can deteriorate.


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P.O. Box 202
Marstons Mills MA 02648