Chimney Inspections

Custom Stove Installations & Peace of Mind

 

Custom Stove Installations offers chimney inspections to determine the safety of your fireplace. We begin every job with a thorough inspection of the chimney because we know that it is critical to the safety of your home. We check for soot and creosote buildup which can lead to chimney fires. We inspect  your chimney for blockages from birds’ nests and other debris that can find its way into your chimney. And, we inspect for structural integrity of the chimney, looking for cracks in the lining on the inside of your chimney and mortar deterioration on the exterior. We check for corrosion and heat damage on the metal components of the chimney.

 

We want to provide you with peace of mind for your upcoming burn season.

 

Chimney Sweeping

Before and after chimney sweep
Before and after chimney sweep

Chimney cleaning is critical to your stove or fireplace's safety and performance!

 

 

 

Cleaning chimney systems including, open fireplaces, wood inserts, wood stoves pellet inserts and pellet stoves. We pride ourselves on thorough chimney sweeps. We have a unique approach to your sweep. We come from an installation background and have extensive knowledge about your stove as well as your chimney. We do a thorough cleaning of your chimney and cap (if applicable) but we don’t stop there....

We clean the stove as well, including the baffle, fire box, glass and even touch up the paint. Our goal is to make your stove perform as if it were just installed. After our chimney technician performs the chimney cleaning and inspection, we review with our customer everything that we inspected and cleaned. This is a great time to ask about how to operate the chimney, how to operate your wood or pellet stove and even ask about problems you may have previously encountered with your chimney.

 

Today’s wood stoves are extremely efficient. This means that they put more heat in your home than they put out your chimney. This is great, it means that you burn less wood and get more heat. However, there is a small drawback. With less heat going up the chimney you get a cooler chimney temperature. Cooler chimney temperatures result in more soot build up. The longer soot stays in the chimney the more likely it is to turn into creosote and create a fire hazard in your home. Newer stoves need to have their chimneys swept more frequently than their older counter parts.

 

Creosote

How Creosote Forms

From the Chimney Sweeps Library

In a laboratory, using an oxygen bomb calorimeter to burn bone-dry wood (0% moisture content) in an atmosphere of pure oxygen, fly ash and steam might be all you'd find in your chimney. In the real world, however, wood combustion is never that complete.

Incomplete combustion adds a couple of extremely combustible components to wood exhaust; namely, unburned volatiles, carbon, and wood particles, which permeate the blend that eventually condenses in the chimney.

Even the most efficient fireboxes produce SOME unburned exhaust gases, volatiles and particulates. Cook up some wine and collect the condensation, and you'll get concentrated, high-alcohol content brandy. Cook up some wood, and the condensation that collects in the chimney will be highly concentrated, ultra-combustible creosote.

So, you might ask, if these components of wood exhaust are so highly combustible, what keeps them from burning up in the fire?

Actually, there are several factors that contribute to incomplete combustion (and creosote formation):

Primitive stove design: Until the relatively recent development of EPA approved stoves, there simply wasn't enough heat or air in the typical firebox to enable even partial combustion of the wood exhaust. These older stoves, which we call "Smoke Dragons", sent nearly all of the unburned volatiles and particulates from the fire right up the chimney. EPA stoves incorporate a "secondary burner", where pre-heated air meets the unburned particles and exhaust gases on their way out of the stove and ignites them, burning up most of the leftovers from the primary fire.

Excess water: While it is true that no matter what you do, there will always be a small amount of water vapor in wood exhaust, it is also true that every effort should be made to hold it to a bare minimum. Green or rain-wet wood can produce so much steam that it can prevent the secondary burner in even the most efficient EPA-approved woodstove from firing off. To make matters worse, this steam then mixes with the unburned exhaust, cooling it down, increasing its density and slowing its flow rate up the chimney. All of this contributes to increased condensation (creosote buildup) in the flue.

Insufficient air supply: "Airtight" stoves are called that because the operator has the ability to adjust the rate of burn by regulating the air supply to the fire. If the air control is shut down too far or too soon, there might not be enough air in the firebox to promote complete combustion, resulting in an increased amount of unburned wood gases and particulates in the exhaust.

Cold or oversize chimney flues: Since creosote condenses inside the flue as the wood exhaust cools, it is important to keep the exhaust gases hot and flowing briskly until they exit the chimney. To this end, the ideal wood stove chimney is made of insulated stainless steel, is the same size as the flue collar on the stove, and runs straight up through the room-temperature air in the middle of the house. The worst case scenario would be an oversize, rectangular masonry chimney that is exposed to cold outdoor temperatures for its entire length.

Creosote always originates as a liquid condensate, but, depending upon the variables outlined above, eventually takes one of three forms:

Stage 1: Velvet Soot. The product of hot, dry-wood fires, Stage 1 is the least combustible and easiest to sweep type of creosote.

Stage 2: Porous & Crunchy. An increase in unburned volatiles and particles in the exhaust causes this heavier, stickier, harder to sweep formation.

Stage 3: Glaze. This occurs when fresh layers of liquid creosote condense so rapidly that previous layers don't have a chance to dry out and solidify. Glaze starts out as a gooey, tarry mass, then eventually hardens like a rock, and can't be removed by conventional sweeping.

The bottom line: Even if you're burning bone dry wood in a super-efficient EPA approved stove and always give the fire plenty of air, you should check your chimney at the end of every burning season and remove any creosote that has accumulated.

Common Problems With Chimneys

Smoke Smell In House When Fireplace Not Burning

From the Chimney Sweeps Library...

Q: We just bought a house, and are grappling with a rather strange problem with our fireplace. We might expect to smell a little smoke when we have a fire going, but we don't. We notice a strong smoke smell that comes from the fireplace when we're NOT using it. We had the chimney cleaned and it didn't help (maybe our Sweep didn't do a good job?). Do you have you any idea why our fireplace smells so smoky, and what can we do about it? -Lionel

A: Wood-burning fireplace chimneys smell smoky whether they've just been swept or not, because no matter how thoroughly your Sweep brushes the flue, he can't possibly remove every trace of soot and soaked-in creosote. Even if he were able to sand-blast every microscopic remnant of wood smoke deposits out of the flue, the very first wood fire would deposit a fresh layer, and the pungent, smoky odor would return. So the real question isn't why your fireplace smells smoky: the question is, why is the odor entering your house?

First, let's consider the fact that even the most tightly constructed homes have many, many openings (or air pathways) to the outside. There are intended air pathways, such as ventilation intakes, kitchen & bathroom exhaust fans, clothes dryers and combustion appliance flues, to name a few. There are also numerous unintended pathways, such as electrical, plumbing, cable and ductwork penetrations, leaky windows and doors, unsealed building cavities, ventilated flashings around vents and chimneys, etc.

Companies that perform air infiltration testing express the total of all these air pathways as if they were put together into one big hole. It is not uncommon for a supposedly "tight" house to have an air pathway total of over 400 square inches, the equivalent of an open window measuring 20 inches square! At any given moment, air is transferring out of the house through some of the pathways that make up this 'window', and replacement air is entering through whichever of the others offer the least resistance.

The biggest air pathway to the outside in most houses is the fireplace chimney. A fireplace chimney can allow airflow in both directions. When in use, a fireplace chimney is a powerful evacuating force: the chimney updraft created by an open fireplace fire can move hundreds of cubic feet of air per minute out of the house, in many cases more air than the other pathways combined can supply! This is why you don't smell the smoky odor when a fire is burning in the fireplace: it is only when the fire dies down, and the updraft diminishes to the point where evacuation from other sources overcomes it, that the airflow in the fireplace flue reverses and the odor returns.

So what other forces are evacuating air from the house, causing makeup air to be pulled in through the fireplace chimney? At any given moment, a combination of evacuating forces might be at work. Some are mechanical, as is the case with unbalanced central heating and air conditioning systems, exhaust fans and clothes dryers. Some are from natural causes, as when the wind blowing against the house creates positive pressure on the windward side and negative pressure on the leeward side. Some are thermal, like the rising exhaust gases in woodstove, furnace or water heater flues.

Another example of thermal evacuation is the so-called "stack effect". Heated air has lower density than cold air, so the warm, buoyant air in your house wants to rise through the roof, while the cold, heavy air in your unused fireplace chimney wants to flow downward into the house. If there are pathways in the upper stories or roof to allow the rising room air to escape, the warm air will flow up and out of the house and replacement air will flow down the chimney and in through the fireplace. The stack effect is more pronounced in taller, leakier houses and in houses with cold chimneys (like chimneys on outside walls, exposed to outdoor temperatures for their entire length). Rainy weather also accelerates the stack effect, because the wet air entering the chimney is heavier than the dry air in the house.

Whatever the cause, whenever air travels to the outside of the house, an equivalent amount of air attempts to enter somewhere to replace it. If the chimney offers the path of least resistance for the makeup airflow, the smoky smell of wood creosote will enter the house along with the replacement air.

What can you do to stop your house from using the fireplace chimney for makeup air? All you need to do is create enough resistance to the flow of air down the chimney so that the other air pathways will provide less resistance to nature's tendency to equalize air pressure inside and outside the house. Here's some ideas:

1) Close the fireplace damper when not in use. This will sometimes do the trick, although a damper alone may not provide sufficient flow resistance, as most fireplace dampers are pretty leaky.

2) Add a good, tight-fitting glass firescreen. This will quite often solve the problem, and will also inhibit the flow of heated air OUT of the chimney when there's a fire going.

3) Consider a top-sealing damper. These mount at the top of the chimney, and are opened and closed via a stainless steel cable running down the inside of the flue.

4) Provide a source of outside combustion air to your other combustion appliances. If your gas furnace, oil furnace, woodstove and water heater aren't siphoning air out of the house, the demand for replacement air will be reduced.

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Anything that is drawing air out of the house (and causing return air to be drawn in) is suspect when chimney odors are entering your house. In our experience, closing the damper and installing a glass firescreen will often provide enough resistance so that the return air seeks different entry points.