Ready to order your custom cap before installation day? Browse our custom chimney caps → — custom fabricated to cover your entire chimney top. Ships anywhere in the USA.
A custom chimney cap — also called a chimney topper, chimney rain cap, or chimney cover — is made to your exact dimensions, which means installation is usually straightforward. That said, there are a few things worth knowing before you climb up there, especially if you're installing a larger cap or working with an unusual chimney configuration.
Top Mount vs. Side Mount: Know Which One You Have
This is the first thing to understand. The mounting style determines how your cap sits on the chimney and how it's secured.
- Top mount: The cap's base sits flat on top of the chimney crown. This is the most common configuration and the easiest to install. The cap is typically secured with construction adhesive or masonry anchors through the base flange.
- Side mount: The cap has a vertical skirt that wraps around the outside of the chimney and is secured with screws through the skirt into the masonry. This style provides full crown coverage and a tighter seal against wind-driven rain.
When you order from us, let us know which mounting style you need. If you're not sure, send us a photo and we'll tell you which is appropriate for your chimney.
Before You Install: Check the Crown
Before setting the cap, take a close look at the chimney crown — the flat masonry surface the cap will sit on. Look for:
- Cracks or crumbling mortar that should be repaired before the cap goes on
- Uneven or sloped surfaces that might affect how the cap sits
- Old caulk or sealant from a previous cap that should be cleaned off
Installing a new cap over a damaged crown is a missed opportunity. A few dollars of mortar repair now prevent moisture from working under the cap base and accelerating crown deterioration.
Setting the Cap
For a top mount cap on a standard flat crown:
- Set the cap in position and confirm it's centered and square on the crown
- Mark the anchor points if using masonry screws
- Drill pilot holes with a masonry bit if required by your anchor hardware
- Secure the cap — most of our caps have pre-drilled mounting tabs or legs for this purpose
- Apply a bead of high-temperature, paintable masonry sealant around the base perimeter where the cap meets the crown
For larger caps (48" and above), having a second person on the roof makes positioning significantly easier. These caps are not heavy but they're awkward to maneuver solo on a rooftop.
Sealing: Do It Right
The seal between the cap base and the crown is what keeps water from migrating under the cap. Use a sealant rated for masonry and outdoor exposure — standard silicone caulk is not ideal here. We recommend a high-temperature masonry sealant or a product specifically rated for chimney crown applications.
Apply a consistent bead around the full perimeter of the base, smooth it with a wet finger or tool, and let it cure fully before the cap sees any rain. Most masonry sealants need 24–48 hours to cure.
LTL Freight Delivery: What to Expect
Our caps ship via LTL freight in a custom wooden crate. A few things to be prepared for:
- Delivery will be by full-size 18-wheeler. If your property or street can't accommodate a large truck, contact us before ordering and we'll arrange terminal pickup or a smaller vehicle.
- The freight company will call ahead to schedule delivery. Make sure your contact number is correct on your order.
- Inspect the crate before signing the delivery receipt. Any visible damage to the crate should be noted on the receipt.
- The cap inside is secured to prevent movement — take your time unpacking and keep the crating materials until you've confirmed the cap is undamaged.
When to Call a Pro
Most chimney cap installations are well within DIY territory if you're comfortable on a roof. That said, consider hiring a chimney professional if:
- Your roof pitch is steep, or the chimney is difficult to access safely
- Your chimney crown needs significant repair before the cap goes on
- You have a multi-flue configuration with an unusual layout
- You're installing a very large cap (72" and above) that requires more than two people
A chimney sweep or mason can typically install a cap in under an hour and will often do it as an add-on to a regular cleaning or inspection visit.
Questions Before You Install?
We're happy to answer installation questions for caps we've built. Call or text Sean directly at (609)352-9840. We've been building and talking through installations with customers for 32 years — there's not much we haven't seen.
Not sure how to measure? Check our measuring guide → or reach out for a custom quote.
"Fantastic fit and finish, excellent communication from start to finish. A trusted craftsman." — Charlie
Browse our custom chimney caps → — custom fabricated to cover your entire chimney top. Ships anywhere in the USA.
Sean has 32 years of experience fabricating and installing sheet metal components, copper roofing, and custom architectural metalwork — including historic preservation projects on schools, churches, and government buildings. Every cap that ships from Archaic Metal is built by hand in New Jersey.