It’s Not Just Saint Nicholas Who Came Down the Chimney! Chimneys and Pest Control

By Chris Williams on December 29, 2017.

Now that Christmas is another happy memory and a New Year is fast approaching, I think it is a great time to talk about chimneys and pest control.  Although many newer homes lack a conventional fire place and chimney of block, brick, and mortar, all heating systems require ventilation.  Newer systems are designed with efficiency in mind and in most cases have sealed intake and vent ports.  Older homes that have been re-fitted with newer heating systems will sometimes use old chimneys to vent, or in cases of a gas fire place, the intake line fits within the 8 inch exhaust pipe, inside the old chimney.   Older homes or homes with working fire places may have several separate chimneys, and 3 or 4 fireplaces.  Starting from the top of the chimney or flue, we highly recommend chimney caps.  Chimney caps are devices that are installed on top of chimneys to prevent wildlife from entering the chimney.   Because chimneys are designed to vent dangerous gasses from a structure, chimney caps may have fairly large openings. Depending on the brand of chimney cap and system specifications, most chimneys can be adequately sealed off by a professional installation technician.  Chimney caps may not exclude baby mice, or insect pests, and should be inspected periodically for damage.  Heading down the chimney we meet the roofline.  Central chimneys are surrounded by lead or copper flashing material where they enter the roofline.  Side mounted  chimneys may or may not be free standing, depending on the age of the structure, and may also have flashing at the roof line.  Chimney flashing is used to keep water out of the roof.  The flashing material is built into the bricks and integrates with the roofing material.  Defects in flashing can lead to water damage to roof and chimney, as well as allow wildlife and insect pests to enter the roof line and attic spaces.  Side chimneys may also have a gap running up the entire length on  both sides, a great place to hide or make your way into the attic eaves if not properly sealed during construction.  Continuing down the actual chimney, depending on the type of chimney itself ( block tile with liner, brick/block tile with liner etc.) there could be actual  pieces of the chimney missing.  Gaps and missing bricks could allow access to the interior of the chimney, and then the house itself. Gas replacement stoves and fireplaces may have a space between the interior lining of the flue and the 8 in. inner line feeding and venting them.  Moving farther down the inside of the chimney, we come to the “throat damper”.  This device allows the flue to be closed off from the inside, above the fire box.   When open the throat damper is used to control the draft into the chimney, when closed the  damper prevents cold drafts and other things from coming into the firebox.  Some fire places have fairly tight enclosures or windows that close the firebox itself, while others are wide open to enjoy the fire.  Finally, we end up either outside at the base of the chimney or in the basement below the chimney. Here we find the cleanout shoot and the ash box.  The ashes and debris from burning may be swept or pushed down the shoot into the ash box where they may be removed.  Periodic inspection of these areas is recommended, ash and debris build up within the structure can lead to potential fire damage.  Regular chimney cleaning and inspection are part of living safely with fire.

Now that we understand what a chimney is, and can visualize the different parts of the chimney we may discuss some of the Pest Control issues that chimneys present.  Over the years Pest Control Professionals have been called out some very strange situations involving chimneys.  From the top, poor conditions on the roof line lead to moisture.  Carpenter ants love moist areas!  Sometimes the nest is located in or near soggy roofing associated with a leak near the chimney.  Wasps will sometimes overwinter in chimneys along with cluster flies, stink bugs, ladybugs, conifer seed bugs to name a few.  Most will leave the way they came, but sometimes find their way into living spaces causing a minor nuisance.  After using the fireplace, be sure to close the damper to exclude these pests.  Insects in the chimney may also indicate a dead animal or other organic material.  Large numbers of carpet beetles or larder beetles, shiny flies, odors, etc. should be investigated.  At one home, larder beetles( feed on dead animals etc.) were all over a bed room in the addition.  Most of the activity was centered under a dresser.  When I moved the dresser, there was the ash box.  Inside was the carcass of a Canada Goose, yes a decomposed Canada Goose!   What Next?    Bats will enter chimneys to rest, or escape bad weather.  Bats also take advantage of poor flashing along rooflines and around chimneys.  Large colonies of bats can enter through small openings and can be costly to remove.  On more than one occasion I have been called out to find or remove a bat in the house, which can be darn near impossible.  How did the bad get in the house?  Most of the time I find the throat damper broken and not closed, just wide open, or missing altogether.  It is likely the bat either fell or was unable to get back out the top of chimney and came through the fire box.  I have had Red Squirrels, Grey Squirrels, Flying Squirrels, mice, ferrets, birds, skunks, raccoons, and  opossums end up either in the house or stuck inside the chimney.  Just last week I was called out to Alton, New Hampshire for a Flying Squirrel in a home.  A day prior, the cats were staring at the living room wall, motionless.   At first the homeowner did not notice anything, then it jumped right on her shoulder and into the TV enclosure.  With great haste, she closed the doors to the TV, and taped them shut, and unplugged the TV. Things were very quiet overnight.  When I arrived the next morning there had been to activity or sightings, cats were acting normal.  I looked around the room carefully and did discover the throat damper to the recently cleaned chimney was Wide Open! Turning my attention back to the TV enclosure, ready with gloves, safety glasses, bucket and bags, I un-taped  the doors.  Opening slowly, and …..nothing moved or jumped out?  Using a flash light and mirror to see behind the TV, I could see it.  A small grey Flying Squirrel, dead behind the TV.  Although the homeowner disconnected the power cord, it was not fast enough, and the Flying squirrel was electrocuted chewing the wires. (see photo)  Rodents of all types readily chew and damage wiring in structures, causing fires to start.  A well installed Chimney Cap will prevent 98% of animals in the chimney, along with regular inspections.  Colonial Pest Control has a team of Wildlife Specialists ready to assist you with the control of Bats, Squirrels, Mice, Rats and other nuisance animals.  Our technicians use only safe and legal methods designed to be effective and long lasting.  All of our work is covered by warranty ( see applicable contracts ) and done to the highest standards.  Colonial Pest Control also handles Pest Control in both Commercial and Residential  settings.  Give the Professionals a call at 1-800-525-8084!

Tim Chace



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