Capping Unused Chimney

Align the open bottom of the cap with the top of your chimney flue.

Capping unused chimney.

There are so many different options nowadays to cap off an unused chimney. Chimney c caps are a plastic terracotta cap with an bird insect guard that sits in side the cap. Apply a bead of butyl rubber caulk around three sides of the chimney at. Slide the cap over the top of the flue.

One old and virtually free method of capping off or sealing a chimney that is generally no longer used is to make a lead cap. Slowly lower the cap onto the flue and push it down as far as it will go. If you are only talking a few feet of redundant flue then you ll probably be ok with fully capping after reducing the height with a single vent left in the blocked up fireplace. Put on heavy work gloves and use tin snips to cut a piece of sheet metal to the same measurements as the chimney opening.

There are a few products you can purchase to block the chimney just above the damper. Single flue caps are the easiest to mount since they sit right on top of the flue. Spring loaded legs are fitted securely to the base of the cap which allow the cap to be securely fitted to the chimney pot. Unused though they can waste a lot of heat up the chimney.

Usually unused chimneys are capped off with a bent sheet metal covering and perhaps a wire strap or weight on the top. These can simply be made out of a scrap or an offcut of lead beaten into the correct shape and bonded to the top of most chimney pots to effectively seal it and make it waterproof. The bottom is even easier. The rain cannot get in but it is not sealed air tight which does allow any inside moisture to slowly get out.