How to Build a Chimney Cap

Lead Image
  • 2-3 hours
  • Intermediate
  • 100-200
What You'll Need
Sheet metal (stainless steel, copper, or similar metal used around chimneys)
Thick wire mesh (3/4" or 5/8")
Welding tools
Tape measure
Sheet metal sheers or comparable saw components
Zip ties

A chimney cap can be an essential part of your home because it prevents animals, leaves, and debris from falling into your chimney. Some of these units can actually add drama and aesthetic appeal to a chimney, and others are just made to work well. There are a few different varieties of chimney caps out there, depending on the flute style of your unit. Try to adjust this guide according to your situation. This is made for square or rectangular units, but you can adjust to suit round ones. For the basics behind chimney caps, however, read the guide below.

Step 1 - Measure for Your Chimney Cap

A chimney cap is basically a metal base that sits along the rim of your chimney, topped with a mesh box and a metal cap above that. To plan out the construction of your cap, first measure the edges of the chimney top. You will want the adhere the cap to the rim so measure how long it is on each side and how thick it is. Make note of those measurements.

Step 2 - Cut out the Base of the Chimney Cap

Once you know how thick and long each side of the chimney top is, you can figure out what size you need your base to be. In essence, you will need four strips to go on the top of the chimney, and you will need four more equally sized strips to make a 90-degree angle with those and hold the mesh top in place. Cut two of each piece that corresponds to the measurements you took before. Make sure they all and up being the same thickness if they aren't.

Step 3 - Assemble the Base

To make the base, start by welding each pair of metal sheets together so they form even, 90-degree angles. The weld will be along the long side of the sheet. Once all the pairs are done, set them up so that they mimic the top of your chimney. This will look like a flat rectangle with each of the welded pieces pointing up on the inside of the rectangle. All of your pieces should meet at a corner. Weld those corners together.

Step 4 - Make the Mesh Top

Cut out pieces of your mesh that are inches high and the same length as each side of the inner rectangle you just welded together. Then cut a mesh rectangle that is the same size as that inner rectangle. Weld each piece of mesh to the corresponding side it belongs to and weld the corners. You should have a mesh stripe on top of the base now. Position the mesh rectangle on top of this and weld it on.

Step 5 - Make the Cap

The final cap is simply a piece of your sheet metal cut one inch larger than your inner rectangle all the way around. Cut this out and weld to the top of the mesh. Bend the edges down slightly.

Step 6 - Install the Cap

For installation, either use masonry adhesive or drill holes in the base to attach it with masonry anchors.