Damper Repair & Installation in Maryland

The damper is the closeable plate inside the chimney that seals the flue when the fireplace is not in use. A working damper is the difference between a fireplace that adds character to a room and a fireplace that operates as a 24/7 conditioned-air leak straight up the chimney. Most Maryland homeowners with working fireplaces are unwittingly losing 8 to 15 percent of their heating and cooling energy through a damper that no longer seals — either because the steel throat damper has rusted and warped, or because no damper exists at all. Eagle Chimney Service repairs, rebuilds, and replaces dampers across Maryland with a strong preference for top-sealing damper systems that solve the energy-loss problem permanently.

A throat damper is the traditional cast-iron or steel plate mounted just above the firebox. It has a handle or chain you pull to open and close. Throat dampers have two problems. First, they live in the path of corrosive combustion gases and condensation, so within 15-30 years they rust to the point where they no longer seal flat. Even a damper that looks closed may be losing significant air through warped gaps. Second, they are mounted low in the chimney, so the airspace above the damper is open to the outside, and warm air still leaks past the imperfect seal continuously. We can rebuild throat dampers — replace the assembly, install new gaskets, and restore proper operation — and we do when the existing setup is structurally sound and serviceable.

A top-sealing damper is mounted at the crown rather than at the throat. It uses a silicone rubber gasket that seals against a polished metal frame, creating an airtight closure equivalent to a storm window. It is operated by a stainless cable that runs down the flue to a pull handle inside the firebox. When closed, it seals the entire chimney from the top down — air cannot escape past the damper, nor can rain, animals, or downdrafts enter. Most top-sealing dampers also incorporate the cap and animal guard in one unit. Lyemance and Lock-Top are the two leading brands, both backed by manufacturer warranties. The energy savings on a typical Maryland home with an existing throat damper pay for the upgrade in one to three heating seasons.

We install top-sealing dampers as a single-visit job — measure the flue at the crown, custom-order or in-stock the right size, install with stainless fasteners and high-temperature sealant, run the operating cable, and demonstrate operation to you before we leave. For homeowners who prefer to retain a working throat damper, we provide complete throat damper service: assembly replacement, frame repair, new operating handles and chains, and replacement gasket material rated for high-temperature service. Every damper job ends with a draft test to verify the damper is fully open during operation and a seal test to verify it closes airtight when the fireplace is not in use.