Animals like birds and rodents can get into your fireplace chimney and cause problems. The good news is that animal damage inside the chimney is rarely severe. A good cleaning along with repairs to keep them out should solve the problem.
1. Foul Odors
One of the first signs of animal issues for those not actively using the fireplace may be odors. These odors are a combination of animal urine and feces, along with the musky odors of the nesting materials and the animals themselves. If you notice any odd odors emanating from your chimney or fireplace, then you need to have it inspected for animals.
2. Missing Chimney Cap
The chimney cap is the device that sits atop the chimney. It serves two purposes -- it keeps embers from blowing out of the chimney and onto the roof, and it keeps animals from getting into your chimney to make nests. It typically looks like a metal cap or cage atop the brick portion of the chimney. If there is no visible cap or if the cap looks loose and askew, it is time to have it replaced or repaired.
3. Hearth Debris
Your hearth should contain nothing more than a bit of charcoal and ashes from the wood you burn. If you notice other debris, such as dried grasses, paper and other fibers, or sawdust-like materials, then pests are likely nesting inside the chimney and the excess materials are falling into the hearth. This is especially dangerous, as nesting materials can lead to chimney fires if the chimney isn't cleaned properly before its next use.
4. Odd Noises
Scratching and rustling should never be heard from the chimney. These sounds are made by animals in most cases, which means your chimney is not safe to use until the animals are cleared out and any associated debris is cleaned out. Occasionally, these sounds can be made from a loose chimney cap blowing around in the wind or wind coming through failing mortar on the chimney's brickwork. These should also be repaired, both for structural safety and to keep animals out.
5. Smoke Blowback
One of the more frightening and inconvenient issues with animals blocking up a chimney with nesting materials is when smoke and soot blow back into your home when you try to light a fire. This is dangerous to your health and the chances of a fire are a concern. Don't use the fireplace if this occurs until after it has been cleaned and repaired by a professional.
Contact a chimney service if you are having any of these problems. Continuing to use the fireplace and chimney could otherwise be hazardous.