A Beginner's Guide To Sealing A Chimney Crown

Posted on: 23 January 2015


Few of the pleasures of home rank as high as that of a fireplace. But keeping a fireplace in good working order entails periodic chimney maintenance. If you would like to learn more about performing basic chimney maintenance yourself, read on. This article will explain the process of sealing your a chimney crown.

Chimney Crowns

The crown is perhaps the most important element of your chimney. This slab of mortar or concrete sits atop the bricks that make up the chimney stack. It is responsible for preventing water from penetrating the gap between the bricks and the chimney flue inside.

As time goes on, cracks inevitably form in your chimney crown. This is a normal bi-product of the seasonal cycles. Yet such cracks, if left untreated too long, will eventually cause the mortar between the bricks to deteriorate. Not only that, but they can lead to even more costly forms of damage inside of your home. 

Sealing Cracks In The Crown

The good news is that repairing cracks in your chimney crown is relatively easy, so long as you are comfortable working on the roof. Here are the supplies you'll need to get started:

  • roll of duct tape
  • canvas drop cloth
  • stiff nylon brush
  • wide paintbrush
  • tub of brushable crown sealer

The Process

Sealing a chimney crown is not a time consuming process. That said, it is important to think a few hours ahead. Before you begin, check your local weather to make sure that there is no chance of rain for at least the next four hours. Otherwise, not only will you have to make another trip to the roof, but you'll have a big mess to clean up when you do.

Start by scrubbing any dirt or debris from the crown with your nylon brush. A clean surface is necessary for the sealer to adhere properly. Now lay out your canvas drop cloth around the chimney. This will help keep any sealant from landing on your shingles.

Next take a long strip of duct tape and wrap it around the chimney just below the crown, leaving about a 1/4" gap between the two. Repeat this process with the flue liner extending upward from the crown. The tape will help to keep the edges of the sealant looking nice and tidy.

With these preliminaries in place, you're ready to apply the sealant itself. For this task use your paintbrush, making sure that the crown is covered entirely. If you find it easier, you may also use your hand to spread the sealant--so long as you are first don a disposable glove.

Allow the first coat of sealant to dry until tacky and then use your brush to apply a second coat. Clean up any spilled sealant before it dries, using water. Wait about an hour until the sealer feels dry and then peel of the duct tape from chimney and flue. Voila, your chimney crown has now been successfully sealed! 

If you need assistance with this process, or any other chimney repairs, contact a local masonry company, like A1 Everlast Construction.