How A Homeowner Can Apply A Rubber Membrane To A Concrete Crown On A Chimney

Posted on: 15 June 2016

Concrete chimney caps routinely crack and break apart over time. The chimney cap should be inspected every couple of years to see if small cracks are developing in the concrete. If you see cracks developing, you can apply a rubber membrane to the surface of the cap to keep moisture and ice out of cracks to extend the life of the cap. Moisture and ice seeping into the concrete are the main reasons a chimney cap cracks. The process of applying the rubber membrane is simple, but you will need to know how to work on ladders and roofs for your own safety. If you are able to climb up on your roof to inspect the cap yourself and you see small cracks, here is how you can apply a rubber membrane to seal the cap.

You Will Need:

  • Rubber Membrane Material
  • Brush
  • Duct Tape
  • Spray Bottle of Water
  • Rubber Gloves

Tape Chimney

You want to use to duct tape to tape off the chimney in much the same way you would tape around windows and doors when painting a room in your house. If the rubber membrane gets on the bricks or on the tiles that stick out of the top of the chimney, it will be very noticeable and detract from the beauty of the exterior of your home.

Place a row of tape on the bricks directly under the cap and a row at the bottom of the tile where it protrudes from the cap before you apply the membrane.

Rubber Membrane

You should get an elastomeric rubber membrane to apply to the cap. An elastomeric rubber membrane will expand and contract with concrete as temperatures get warm during the summer and cold during the winter. 

Applying the Membrane

You should use a 2" to 3" wide medium-bristled paint brush to apply the membrane. First, use the paint brush to sweep off any debris and dust that might be lying on the cap. Take your spray bottle full of water and apply a light mist of water over the cap. The water helps reduce the friction on the concrete so you can more easily spread the rubber membrane material.

Put on some rubber gloves to protect your hands and open the can of rubber membrane. Apply a thin coat at first and work the material down into the cracks and pores of the concrete with the tip of the brush. Wait for about an hour for this first coat to dry.

Once the first coat dries, you can apply a thicker coat of rubber membrane material onto the cap. Apply a thick coat evenly over the cap and make sure all gaps are filled. The thicker coat will take about a half of a day to dry. Remove the tape after you apply the second coat and let the product dry.

For professional help, contact a company like Excel Chimney & Fireplace Service.


No Place Is As Important As Where You Live

I'm Maryann Delgado and I am very happy with the success my life has brought. One thing I have learned is to never underestimate the importance of your property, whether it is a storefront or your home. We spend the majority of our time in our homes, working and living our lives. I have visited many properties that just feel off. Those who live in work on these properties don't understand the changes that can be made to how they construct their buildings. I have had to learn everything I can about construction in order to build my perfect home and I have many lessons I'd love to teach to others.

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