How to install a chimney cap

 On occasion, homeowners will have to replace their chimney caps.  This most commonly results from the caps blowing off. Most companies include chimney cap installation as part of their available chimney repairs. Using a professional installer provides the added benefit of discovering unknown problems at their early stages. However, some homeowners prefer to install the chimney cap themselves.  This article was created for those do-it-yourselfers who want to install their chimney caps.  Here you will find information that you need to know about how to install a chimney cap. 

installed chimney cap

What to do before you start replacing the chimney cap

  • Take the time to identify the type of chimney cap you have
  • Identify the flue your chimney has
  • Use parts from the original manufacturer
  • Review any instructions that may have come from the manufacturer
  • Verify that you have all of the required tools

Chimney cap options

There are several options available for replacing a chimney cap:

  • Fit over a flue
  • Friction fit
  • Multi-Flue Cap

Fitting the chimney cap over a single flue

single flue chimney cap installed

The most common type of chimney cap is one that fits over a single flue. Single flue chimney caps do not require any special tools. However, it does need you to be on top of your roof.  Do not attempt to do this if you are not 100% comfortable with heights.  The single flue chimney cap should cover between one and three inches of the flue. There should also be at least five inches between the top of the chimney flue and the chimney cap lid so that there is proper air flow. Once the positioning is where it should be, the screws should be tightened from all sides.

Installing chimney caps with friction fits

installed friction fit chimney cap

ome chimney caps fit in with a friction fit.  Friction fits are common when there is a metal flue.  Using a chimney cap with a friction fit can be challenging.  As a result, it is best to have a chimney technician install it for you.  If you choose to do it yourself, It is important to make sure that the cap you are installing has been approved for use on the chimney model.  Steer clear of parts that are not created by the original manufacturer.  If the original parts are not available, it is best to have a chimney expert.  The expert can use their knowledge to select the proper aftermarket part. The cap should be placed firmly into the metal flue. From there, it is sealed into place with a silicone sealer. If there are two or more concentric pipes, also known as air-cooled flues, you will need a special type of chimney cap. This will allow the cooling air to flow sufficiently from pipe to pipe.  Once again, make sure that you use caps from the manufacturer of the caps. 

Installing a multi-flue chimney cap

installed multi-flue chimney cap

The multi-flue cap is the most challenging type of cap.  Multi-flue caps are commonly found on masonry chimneys.  These caps extend across the entire chimney crown. This is different from a single flue cap which only covers the flue.  The cap can be anchored on top of the concrete crown.  They come in a variety of styles.  The challenge comes from the fact that proper installation requires the installer to put the cap into position, pre-drill holes in the concrete and then mount the cap. Improperly drilled holes can result in the chimney cap blowing off.


There are many people who have attempted to install their chimney caps.  In some cases, it went well.  In others, the cap blew off, or the chimney experienced new damages.  There is a real benefit to hiring a professional.  Many homeowners choose to include chimney cap replacement with a chimney cleaning.  If you decide to do it yourself, it is important to consider all of the aspects of the job and be willing to call a technician to take care of it if you run into difficulty.  

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