It’s nesting season, so that means chimney swifts are back! Chimney swifts often return to the same nesting site every year, so if you had them last year, you’ve probably got them again, cheeping away from inside your chimney. Swift nests are small, and don’t do any damage to the masonry inside your chimney; however, the abandoned nests and other debris are flammable, and can contribute to chimney fires if left during the burning season.
In 2010, the chimney swift’s conservation status was changed to near-threatened, and swifts are protected under Federal law. This means that reputable, law-abiding chimney sweeps are unable to remove the nests while swifts are still living in your chimney. However, the birds will vacate your chimney as soon as the young are old enough to leave the nest (generally by late August or early September), and we can clean your chimney out after that. Once the birds are gone and the nests have been removed, we recommend capping the flue to keep your unwanted houseguests from returning. Ideally, we recommend putting a cap of some sort on before the nesting season begins, but sometimes a family of swifts will move in and set up house before you have a chance to schedule your appointment, and we wind up having to wait until they’ve moved out again.
When it comes to capping the flue, there are a couple of different approaches you can take. The first is a simple single-flue cap (these are made in a range of standard flue sizes, so we’re fairly likely to have the size you need in our warehouse), which bolts onto the outside of your terra cotta flue tiles, and has both a cap to keep rain away, and a heavy stainless steel mesh to keep intruders from making your chimney their new home. A full-coverage cap, on the other hand, is custom-made to the size of your chimney, with a lid that extends slightly past the edge of the existing crown. As discussed in our previous post on maintaining your chimney crown, the full-coverage cap will not only keep rain and animals out of your flue(s), but will serve to protect the masonry of your chimney.