Preparing Your Chimney and Fireplace for Winter

A fireplace that worked fine last winter is not evidence that it will work fine this winter. Chimneys change between seasons, and most of what changes happens where you cannot see it.

Three problems account for the majority of what we find in the fall. Creosote that has built up past a safe level. Animals that moved in over the summer. A cap or crown that has failed and is letting water into the flue. Any of the three can turn a pleasant evening into an expensive one.

Here is what actually matters before you light the first fire.

Creosote is the reason for the annual cleaning

When wood burns, it releases gases and unburned particles that condense on the cool interior walls of the flue. That residue is creosote, and it is highly flammable.

It builds in three stages. The first is a light, flaky soot that brushes off easily. The second is a harder, crunchy layer. The third is a shiny, tarry glaze that is difficult to remove and burns extremely hot if it ignites. A chimney fire in a flue with stage three buildup can reach temperatures that crack masonry and spread into the framing of the house.

What accelerates buildup: burning unseasoned wood, which is the most common cause by far. Restricting airflow by damping the fire down too far to make it burn longer overnight. A flue that is oversized for the appliance, so exhaust cools too much before it exits. Burning softwoods regularly.

Wood should be seasoned six to twelve months, split, and stored covered but with air circulation. It should read under 20 percent on a moisture meter, and a meter costs about the same as a bag of firewood. Wood that hisses, bubbles at the ends or refuses to catch is too wet, and it is putting creosote into your flue every time you burn it.

The general rule is one professional cleaning per year for regular use, and an inspection every year regardless of how much you burned.

What moved in over the summer

An uncapped or poorly capped chimney is an appealing place to nest. Birds, squirrels and raccoons all use them.

Signs you have company: scratching or chirping sounds, a smell that gets worse in warm weather, debris falling into the firebox, or smoke backing into the room because the flue is partially blocked.

Do not try to smoke them out. Aside from being cruel, it does not reliably work and it can drive animals further in where they die and create a much worse problem. Chimney swifts are also federally protected during nesting season, so timing matters.

The permanent fix is a proper cap with mesh sides. It keeps animals out, keeps rain out, and acts as a spark arrestor. It is an inexpensive part that prevents several expensive problems.

Water is the slow damage nobody watches for

Masonry chimneys absorb water. In a climate that cycles above and below freezing repeatedly through the winter, absorbed water expands as it freezes and breaks the masonry apart from the inside. That is the freeze and thaw cycle, and Evansville gets plenty of it.

Points of failure to check from the ground with binoculars, or have someone check from the roof: the crown, which is the concrete slab at the top, cracks and lets water straight in. The cap, which may be missing, rusted or dislodged. The flashing where the chimney meets the roof, which is a very common leak point. The mortar joints, which erode and leave gaps.

Signs from inside: staining on the ceiling or wall near the chimney, a damp smell, white powdery deposits on the exterior brick, or crumbling mortar you can pick at with a finger.

Water damage is cumulative and quiet. It costs a fraction to address early compared to a rebuild.

What a proper inspection covers

Not all chimney service is the same, so it is worth knowing what you are paying for.

A basic inspection covers the readily accessible portions of the chimney and appliance, checking for soundness, obstruction and combustible deposits. This is the standard annual service for a system that has not changed.

A more thorough inspection adds accessible areas of attics, crawl spaces and basements, and is appropriate when you are buying or selling a home, changing the appliance or fuel type, or after any event that could have damaged the system, including a chimney fire, a severe storm or an earthquake.

A cleaning should cover the full length of the flue, the smoke chamber, the smoke shelf and the firebox, with the work area protected and the debris contained. Ask whether the smoke chamber is included. It is frequently skipped, and it is where a lot of creosote accumulates.

Burning safely once you are cleared

Use seasoned hardwood only. Never burn treated lumber, painted wood, plywood, cardboard or trash. These release chemicals into your home and accelerate deposits in the flue.

Open the damper fully before lighting and confirm you have draft. A cold flue sometimes needs priming, which you can do by holding a rolled newspaper torch up near the damper for a minute.

Build smaller, hotter fires rather than large smoldering ones. Hot fires burn cleaner and deposit less.

Use a fireplace screen. Let ashes cool for several days before disposal, and put them in a metal container with a lid, kept away from the house. Ashes hold live embers far longer than people expect.

Keep a working carbon monoxide detector on every level of the house. This applies to gas fireplaces and inserts as much as wood burning ones.

Never leave a fire unattended, and never close the damper while embers are still live.

Get it looked at before the season, not during

The rush hits in October and November, when everyone lights the first fire and discovers a problem. Scheduling in late summer or early fall means better availability and no waiting through a cold week.

K&M Solutions provides chimney cleaning and inspection across Evansville and the tri state area, along with furnace cleaning, air duct cleaning and dryer vent cleaning. We are licensed and insured, and estimates are free. If it has been more than a year since anyone looked at your chimney, that is the place to start.