Home » blog » How to Repair a Chimney Cap [Full Guide]

How to Repair a Chimney Cap [Full Guide]

Made of metal, a chimney cap keeps rain and snow from getting into the chimney. When the chimney cap is faulty, rain and snow can enter the chimney and accumulate behind the walls of the fireplace.

 Your chimney cap can become faulty if the creosote is sent up by the fire, collect on the cap and block airflow.

To repair this chimney cap, you need to clean the creosote. Fortunately, reading this guide will teach you how to repair your chimney by yourself. 

Eat Fireplace Chimney Column Sweep  - Peggy_Marco / Pixabay
Peggy_Marco / Pixabay

Steps to Repair a Chimney Cap

To repair your chimney cap, follow the steps below:

  • Preparation: Wear loose clothing and shoes made from rubber. Using an extension ladder, climb the roof. Ensure you are with a screwdriver and wrench.
  • Remove Chimney Cap: After climbing the roof, the next step is to remove the chimney cap. If your chimney cap is attached to the flue, use a screwdriver to unscrew it. Also, if there are nuts you can use a wrench to hold them while you unscrew the cap. Take the cap and climb down the ladder.
  • Eliminate the Creosote: Using a chisel and hammer, knock the creosote off the cap. Wear your protective gloves and keep your hands clean. After you have knocked off the creosote, gather it in a plastic bag and dispose of it properly.
  • Fix the Joints: When knocking off the creosote off the cap, you may realize that the joints are detached. You can fix this by screwing the joints together using a self-tapping screw.
    Interestingly, you don’t have to drill new holes because a self-tapping screw does that itself. However, you need to clamp the detached joint using a C-Clamp and drive the self-tapping screw with the help of a drill.
  • Fix the Crown: After you have repaired the cap, you need to climb up the ladder to make needed repairs to the crown.
    The crown is a lining made of mortar that surrounds the outside of the flue. With the aid of a scrub brush and water, clean the crown. You must do this to search for cracks in the crown and remove any algae.
  • Applying Sealant: If you discover cracks in the crown, then you need to fix them immediately. You can do this by applying crown sealant with the help of a paintbrush to the crown.
    More so, the crown sealant will serve as a waterproofing product by preventing water from getting into your chimney. However, you shouldn’t use the crown sealant if you notice that the mortar is detached from the chimney.
  • Remove Loose Mortar: To round up your repairs, make use of a chisel to remove any loose mortar around the chimney. However, you need to replace the loose mortar that you have removed. Interestingly, you can do this by mixing powdered mortar and a little water in a tray. This will form a stiff mixture which you must apply to the mortar using a trowel. Importantly, keep the new mortar you have applied away from the chimney opening.
  • Screwing the Cap: The last step is to replace the cap on top of the chimney. You can do this by fitting it around the flue. Alternatively, you can screw the cap to the flue if they are attached. However, you must do this after the crown sealant and the mortar are dried.


Repairing a chimney cap is a very simple thing to do. However, this easy task can prove challenging if you don’t know what to do. By following the easy steps discussed in this guide, you can repair your chimney cap without extra help.

Table of Contents