How You Can Repair a Cracked Parapet to Prevent Roof Leaks

Parapets are an extension in the exterior wall of a building above the roof's surface. Unfortunately, the joint between a parapet and roof surface is vulnerable to cracking, and this can lead to leaks during periods of rain or snow. However, it isn't difficult to fix cracked parapets if you use the right materials and tools. Below is how you can quickly and easily seal cracks in your roof's parapets:

Tools and materials needed

  • Rubberized flashing cement
  • Fiberglass mesh
  • Trowel
  • Whisk broom
  • Wire brush
  • Measuring tape
  • Scissors
  • Gloves
  • Ladder

Step-by-step procedure

1. Make safety your priority — Working on a rooftop, even at your own home, can be dangerous if you don't properly prepare and stay alert. Rooftops contain fall hazards such as skylights, edges, and power lines that can injure or kill you. It is best to wear a harness designed for working on roofs, as they fasten to a temporary anchor point and can keep you from falling or rolling off the roof. Roofing harnesses can be purchased for less than one -hundred dollars from online safety product retailers.

In addition, be sure to wear gloves as you work with roofing cement. It contains sticky asphalt that can irritate skin and be difficult to remove once it adheres.

2. Clean the cracked location — It is important to remove as much dirt and debris possible from the crack and surrounding area on the parapet and roof. Any foreign objects will limit the proper adhesion of the repair and allow water to seep under the edges.

To clean the crack, use a small whisk broom to brush away debris. Vigorously sweep the area and work the bristles down into the crack to remove stuck particles. If necessary, use a wire brush to remove the most stubborn objects that won't easily sweep out of the crack.

3. Cut a piece of fiberglass mesh into the right shape and size — Once the site of the repair is clean, measure the length of the crack with a measuring tape. Next, use scissors to cut a rectangular piece of fiberglass mesh that is 6 inches larger than the crack's length and 6 inches wide. If the crack isn't straight, then cut a piece that mirrors the path of the crack and allow for 3 inches of space on each side of the crack. Round off the corners of the mesh repair piece with the scissors to permit better adhesion at the corners.

4. Apply a layer of rubberized flashing cement — After preparing the piece of mesh, you should use the trowel to apply a one-quarter-inch layer of rubberized flashing cement. Spread the cement over the crack itself and an extra 3 inches on each side of the crack including the top and bottom ends. Be sure to push the cement into the crack to better seal its interior space.

5. Apply the fiberglass mesh repair piece — After the cement has been applied to the crack and surrounding area, place the mesh piece on top of the crack and gently push it into the cement with the trowel. Pay particular attention to the edges to make sure they are embedded in the cement.

After laying down the mesh, apply another one quarter-inch layer of flashing cement on top of the mesh piece. Be sure that it covers all areas of the mesh and that you do not see any part of the mesh after the application. Smooth the edges of the cement so they blend into the surrounding roof surface.

If you need further tips or assistance, you can contact roof and window repair teams in your area.