Regency ® P121-10/P131-10 Zero Clearance Direct Vent Gas Fireplace | 1313|installationFRAMING AND FINISHINGP121-10 - See ThruP131-10 - PierNote: These units arenon-load bearing.1) For ease of installation, frame your fireplace after it is positioned and the vent system is installed. Remember to install the top standoffs. See the "UnitAssembly Prior to Installation" section. Use 2x4's and frame to local building codes.CAUTION: Verify your fireplace dimensions, framing methods and finished wall facing details before framing. Determine the total thickness offacing material - drywall plus ceramic tiles, slate, etc. Allow the finish surface to be flush with the front or side of the unit. Total facing thicknesscan vary from 1/2" (13mm) to 1-1/4" (32mm) thick.2) When locating your appliance on an exterior wall or in a chase, apply a vapour barrier and drywall, as per local building codes. DO NOT INSULATE THEFIREPLACE ITSELF.CAUTION: The unit does not have to be completely enclosed in a chase. The clearance on top of the unit is 0" to the standoffs so combustiblebuilding materials can be laid directly on top of the standoffs. You must maintain clearance from the vent to combustible materials for both rigidand flex, see Vent Clearances in the "Clearances" section.Framing DimensionsP121-10 (See Thru) P131-10 (Pier)A 25"(635mm)minus 2X the finishingmaterial thickness*A 25"(635mm)minus 2X the finishingmaterial thickness*B 42-1/2"(1080mm) B 42-1/2"(1080mm)C 46-3/4"(1187mm) C 45" (1143mm)minus 1X the finishingmaterial thickness** Finish material thickness includes: drywall, ceramic tile, slate, etc.P121 only: The appliance extends 2-3/4" inches further on the vent side.If trying to center the appliance in a room add 2-3/4" to the non vent sidewhen framing. Do not however change dimension (C) as the openingremains the same.