It is important to support the chimney pot before removing the flaunching, especially if you are resetting rather than replacing the pot. Flaunching is the mortar base holding the chimney pot in position on top of the chimney stack. Tie a length of rope around the top of the pot (A) and a second rope around the chimney stack (B). Then secure by attaching a rope from A to B on both sides of the stack. This should hold the pot in position before removing the flaunching.
Use a cold chisel and club hammer to remove the mortar. If the base of the pot is square, it is designed to fit over the flue exactly. If the pot does not fit exactly or has a different shaped base, then the pot will need supporting before replacing the mortar base. Use strips of slate strategically placed around the base of the pot to support it in the correct position. Brush away any unwanted material and dampen the surface of the stack. This is necessary, especially in warmer weather, to stop the mortar from losing moisture too quickly, which would result in cracking. Use mortar consisting of approximately a 1:4 cement:sand mix to replace the flaunching around the base of the pot.
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