Disclosed is an improved sealing element for a regenerative heat exchanging apparatus, such as a Ljungstrom.TM.-type or a Rothemuhle.TM.-type Preheater. The sealing element is mounted to a radial wall to provide a secure seal between the radial wall and an outer housing of the heat exchanging apparatus and prevent leakage between the hot gas conduit and cool air conduit. In one embodiment, the sealing element includes a reinforced mounting strip that is used to mount the sealing element to the radial wall. The sealing element also includes a sealing strip that maintains a sealing contact between the radial wall and outer housing and a support member that inhibits over-flexing of the sealing element. A set of bellows is positioned on the sealing element to provide the sealing element with flexibility and resiliency so that the sealing element maintains contact with the sealing surface even when the heat exchanging apparatus experiences warping and/or distortion from thermal stress.