Capping Unused Chimney

Single flue caps are the easiest to mount since they sit right on top of the flue.

Capping unused chimney.

Slowly lower the cap onto the flue and push it down as far as it will go. One is an inflatable balloon type product that will seal the flue. There are so many different options nowadays to cap off an unused chimney. Spring loaded legs are fitted securely to the base of the cap which allow the cap to be securely fitted to the chimney pot.

The rain cannot get in but it is not sealed air tight which does allow any inside moisture to slowly get out. Chimney c caps are a plastic terracotta cap with an bird insect guard that sits in side the cap. Usually unused chimneys are capped off with a bent sheet metal covering and perhaps a wire strap or weight on the top. Put on heavy work gloves and use tin snips to cut a piece of sheet metal to the same measurements as the chimney opening.

Even new cast iron dampers allow air loss. Apply a bead of butyl rubber caulk around three sides of the chimney at. Slide the cap over the top of the flue. 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.

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. Align the open bottom of the cap with the top of your chimney flue. Unused though they can waste a lot of heat up the chimney. The bottom is even easier.