Installing a chimney cap is an important home improvement project that can protect your chimney and prevent damage. A chimney cap keeps out rain, animals, leaves, and other debris that can clog the chimney and cause water damage or fire hazards. With the right materials and some basic DIY skills, you can install a chimney cap yourself. Here is a step-by-step guide on how to install a chimney cap properly.

Selecting the Right Chimney Cap

The first step in installing a chimney cap is choosing the right one for your chimney. There are several factors to consider when selecting a chimney cap:

Chimney Shape and Size

Chimney caps come in different shapes and sizes to fit different chimney tops. Measure the top of your chimney in multiple spots to find the right fit. Rectangular, square, and circular chimney caps are common. Custom sizes may be needed for oddly shaped chimneys.

Material

Common chimney cap materials include stainless steel, copper, cast iron, and aluminum. Stainless steel is durable, low maintenance, and weather resistant. Copper develops a patina over time. Cast iron is very durable but heavy. Aluminum is lightweight and economical but can deteriorate faster than other metals.

Style

Chimney caps come in different styles. A flat chimney cap just covers the top while a sloped chimney cap is angled to help shed water. Decorative chimney caps add visual interest with detailed metalwork. Extra coverage options include overhanging sides and mesh screens.

Budget

Chimney caps range from $100-$1000 depending on the material, size, and style. Stainless steel and copper are more expensive but very durable, while aluminum is lighter and more affordable.

Once you know the size and style needed, shop around within your budget. Purchase a chimney cap specifically designed for your chimney shape for proper fit and function.

Gathering the Right Tools

Installing a chimney cap requires some specific tools for measuring, cutting, securing, and sealing:

Tape measure
Marker
Tin snips
Screwdriver
Power drill and bits
Caulk and applicator
Work gloves
Safety glasses
Ladder or scaffolding

Tin snips will be needed for custom cutting any sections of the chimney cap if necessary. A power drill with masonry bits is necessary for anchoring the chimney cap. Safety gear like gloves and glasses should always be worn during installation.

Preparing the Chimney Crown

Before installing the chimney cap, inspect the top of the chimney crown:

Clean the masonry chimney crown with a wire brush to remove any loose debris or crumbling mortar.
Repair any cracks or missing mortar so there are no gaps where water can seep through.
Level any uneven spots on the crown’s surface with mortar for a flush fit.

The chimney crown needs to be in good condition to support and seal the chimney cap. Ensure it is clean, repaired, and level so the chimney cap fits snugly on top.

Measuring and Cutting the Chimney Cap

Each chimney cap needs to be customized to fit. Take accurate measurements and cut the chimney cap to size:

Place the chimney cap upside down on a flat surface.
Set the chimney cap centered on the chimney crown temporarily.
Mark where it overlaps on each side and remove.
Use tin snips to cut the chimney cap along the marks so it sits flush.
Test the fit and trim off any excess material as needed for a snug custom fit.

Take your time with the measuring and cutting for precision results. The chimney cap should overlap the sides equally and not leave any gaps where water can leak through.

Securing the Chimney Cap

Once the chimney cap fits correctly, it’s time to fasten it in place securely:

Prepare the Chimney Crown

Sweep the chimney crown clean and apply a bead of sealant around the edges.
Choose either masonry anchors or masonry screws to secure the cap based on your chimney type.

Drill Holes in the Chimney Cap

Place the chimney cap in position on top of the sealant.
Mark where the anchors or screws will go using the pre-drilled holes in the cap as a guide.
Remove the cap and drill guide holes in the marked spots slightly wider than the anchors.

Fasten the Anchors

Set the chimney cap back on the chimney crown, aligning the holes.
Follow manufacturer instructions to insert your masonry anchors or screws through the chimney cap and into the chimney crown.
Tighten the anchors until the cap is firmly fastened and sealed on top.

Proper anchoring ensures the chimney cap stays secure in all weather conditions. Most require 4-6 masonry anchors spaced evenly around the cap.

Sealing the Edges

The last step is applying waterproof caulk around the edges:

Run a bead of high quality caulk along the side edges where the chimney cap meets the crown.
Fill any gaps or cracks thoroughly to prevent water penetration.
Smooth and wipe any excess caulk for a neat finish.
The caulk will dry and seal the cap tightly to the chimney top.

Allow the caulk to fully cure overnight before using the fireplace. The chimney cap installation is now complete!

Maintenance Tips

Proper maintenance is recommended to extend the life of your chimney cap and keep the chimney functioning safely:

Inspect the chimney cap and sealant yearly for any signs of cracks or deterioration.
Check anchor points to ensure the cap is still securely attached with no loosening or corrosion.
Remove any debris accumulation from the cap or screen to prevent blockage.
Replace the chimney cap if it shows major dents, holes, rusting, or other damage.

With periodic inspections and cleaning, a well-installed chimney cap should last upwards of 10-15 years or more depending on the material. Replace damaged chimney caps right away to avoid any potential chimney damage or safety issues.

Chimney Cap Installation FAQs

How much does it cost to install a chimney cap?

On average, installing a chimney cap costs $200 to $500, including the cap and hardware. Custom chimney caps for unique chimneys or historical homes can range from $800 to $1500 installed.

What are chimney caps made of?

Common chimney cap materials include stainless steel, copper, aluminum, cast iron, and galvanized steel. Stainless steel is one of the most popular options because it is durable, corrosion resistant, and requires little maintenance.

How long does it take to put on a chimney cap?

If the chimney crown is in good shape, installing a chimney cap usually takes 2 to 4 hours. Much of this time is spent custom measuring and cutting the chimney cap to fit properly. The actual installation only takes about an hour.

When should you replace a chimney cap?

Inspect chimney caps yearly and replace them if you see visible corrosion, gaping holes, separation from the chimney, or other damage. Most chimney caps last 10-15 years before needing replacement. Severely damaged caps should be replaced right away.

Can I install a chimney cap myself?

Yes, you can install a chimney cap DIY if you have masonry experience and proper equipment. Otherwise, hire a professional chimney sweep to ensure it is installed correctly. Proper measurement, securing, and sealing are critical to prevent leaks.

Do all chimneys need a cap?

It is highly recommended to install caps on all chimneys, including furnaces and fireplaces. Chimney caps prevent internal damage by keeping out animals and moisture that can lead to dangerous chimney fires and drafting issues.

Is stainless steel or copper better for chimney caps?

Stainless steel is more popular because it is economical, durable, and requires little maintenance. Copper is also durable and attractive but more expensive. Either option will last decades with proper installation. The type of metal used comes down to personal preference and budget.

Can you install a chimney cap in the rain?

Avoid installing a chimney cap in the rain or snow if possible. The chimney crown needs to be dry to allow the caulk and mortar to adhere and seal properly. Wait for a dry day without precipitation in the forecast.

How often should chimney caps be cleaned?

Chimney caps should be cleaned at least once a year along with the rest of the chimney. Remove any built-up creosote or debris so it does not impede airflow. Having a chimney sweep clean the cap annually helps extend its lifespan.

Do all chimney caps have screens?

Screens are an added feature on some chimney caps. Screens further prevent debris blockage and animal nesting but may require more frequent cleaning. Chimney caps without screens are still highly effective at protecting chimneys from exterior damage and moisture.

Conclusion

Installing a chimney cap is a straightforward DIY project that can make a big difference in preserving your chimney. When purchased and installed properly, a chimney cap keeps out animals and rain to prevent costly chimney damage. The key steps include measuring and cutting a custom chimney cap for your chimney, securing it tightly with masonry anchors, and sealing the edges with waterproof caulk. With an investment of $100 to $500 and regular maintenance, a chimney cap should last upwards of 15 years or more depending on the material. By following this guide, you can confidently install a chimney cap to protect your chimney for years to come.

How to Install a Chimney Cap