Sealants that are especially designed for high temperatures are needed for seating gaskets, sealing stove pipe, and setting roof flashing, as well as a number of other tasks associated with high temperatures stoves and their chimneys. Special formulations allow the sealants to maintain flexibility even under extreme conditions. Choose the sealant with correct temperature range for your application. Sealants are available in black, red, or clear so you can match brick, roofing materials, black stove pipe, or create a nearly invisible seal wherever it is needed.
What type of sealants do I need for a direct vent gas fireplace?
Generally speaking, high temperature RTV and, in some cases, a resin-based adhesive called mill-pac. The first few pages of the installation manual for any direct vent gas fireplace will list the additional items required for installation.