How to Fix a Roof Leak With Rubberized Tar

• 1

  Locate the endpoint of the leak inside the house. Look up around the joint between the ceiling and walls. Identify water marks by a brownish discoloration along the ceiling or walls. Follow the water line as far as you can. This gives you a relative location to start looking for the leak when you are on the roof.

• 2

  Climb up onto the flat roof. Use a ladder to reach the roof of one- or two-story buildings. Use stairs that reach the roof for taller buildings. Haul up all of your materials to avoid repeated trips up and down steps or ladders.

• 3

  Clean off debris from the roof, using a broom. Inspect the roof as you work, looking for dips, cracks or loose edges around seams. Often these are where leaks form because the roofing paper or tar has dried and cracked at these spots. Dips indicate possible rotting in the roof.

• 4

  Nail down the loose edges of the roofing with the roofing nails and a hammer. Inspect each seam to ensure you have all loose edges taken care of. Mark each repaired area with bright chalk to find it later.

Dips

• 5

  Inspect the dip itself to determine if it is on a seam or beam. Press down around the dip, but not on the dip, to locate any beams. If you find one, you have a rotted wood problem.

• 6

  Apply a thin layer of tar over the dip with the trowel, using the thickness of the roofing shingles as a guide.

• 7

  Set a layer of loose shingles over the tar. Allow the shingles to remain loose so they help build up the dip.

• 8

  Add another layer of tar over the shingles. Extend this layer over the edges of the shingles to secure them in place.

• 9

  Repeat the entire process until the area is level with the surrounding roof.

Seam and Crack Repairs

• 10

  Cover the entire area needing repair with the tar. Start at the lowest point of the roof and work upward. Spread the tar wider than the roofing paper. This keeps the edges of the paper from working loose.

• 11

  Apply the layer of roofing paper over the tar. Lay the next row or section so there is a 1-foot overlay between the rows or sections. Cover all nails and dips with paper.

• 12

  Push the edges of the paper into the tar with the trowel. Push out all air bubbles by working down the paper from top to bottom.

• 13

  Apply a ¼-inch layer of tar over the paper, covering the paper entirely. Feather the tar into the unpatched roof to smooth out the patch. The patch should be level with the surrounding roof. Use force to even out the tar.

• 14

  Spread course sand or gravel over the roof to extend the life of the patch and roof.