How to Cap a Chimney After Installing a Gas Insert with Colinear Direct Venting

What You'll Need
The chosen chimney cap
Heavy work gloves
Tape measure
Caulk gun
Silicone caulk
Putty knife

After installing a gas insert with collinear direct venting, an important step in changing your fireplace over to gas, or when replacing an existing gas stove, is installing a chimney cap. The chimney cap prevents animals from crawling, or nesting, within the venting, as well as helping to prevent rain and wind from causing problems with your stove. Capping a chimney is actually an easy process, and if you want to save some time and money, can be done by any homeowner.

Step 1 - Place the Cap On

The chimney cap that is installed after placing a gas insert into the system must first be placed onto the crown of the chimney. Make sure that the cap fits snugly, and that it effectively covers the flu and the venting system pipes. If the cap does not completely cover the system, it must be returned so that the proper size of cap can be installed. Call the manufacturer ahead of time for the right part size, or ask any clerk at the local hardware store for the right part so that there is no undue delay.

Step 2 - Secure the Cap

After ensuring that the cap you have is the correct one, secure down with sheet metal screws. If you have to secure it to masonry or brick, be sure to pre-drill the holes and use fasteners that are specifically designed for this type of application.

Step 3 - Secure the Cap to the Crown

Fold the flanges of the crown up and around the new cap. Flatten the metal pieces completely, making sure that there are no gaps around the seal. Drill holes through the flange, and then once again using sheet metal screws, tighten them together as much as possible.

Step 4 - Inside Mounted Caps

If the chimney cap that you have chosen to install after the gas insert is in place is an inside mounted style, then the follow steps need to be taken in order to properly install the cap. Push the cap down into the flu. Make sure that it fits snugly and that it is designed for the insert that you have put in. Bend the edge of the metal, or the flange, down so that it secures the unit down. Insert a bead of silicone caulk under the flange to make a weather tight seal. Press the flange down as tight as you can, making sure that the edges are flush and have no gaps throughout the entire area. Before the silicone dries, use a putty knife to remove the excess amounts that was squeezed out when tightening.

Installing a chimney cap after placing a gas insert into the system is a step that any homeowner can accomplish, which saves time and money. With a little research, along with the correct parts and tools, this is a fairly easy job that should only take an hour or two to complete.