How to Prep for Hot Mopping

Hot mopping flat roofs makes it waterproof.

Hot mopping is a process used to apply melted tar on the roof with a mop to secure roofing paper to the melted tar. Hot mopping is used in flat roof installations most commonly used in commercial buildings, where the roofs are built flat. For the hot mopping application to be applied correctly the roof must be properly prepared before hot mopping the roof. Preparing the roof for hot mopping will vary depending on the roof and local building codes but most use the same process.

Things You'll Need

• Base sheet
• Tin caps
• Nails
• Hammer
• Dust pan
• Broom
• Face mask
• Gloves
• Kettle
• Tar
• Buckets

Instructions

1. Install the base sheet to the roof. The base sheet installation varies depending on local building code. Contact your local building department for exact nail spacing and specific installation instructions or your roof will not pass inspection. Most commonly you must nail the roof with tin caps and nails every eight inches.

2. Sweep the base sheet completely with the broom. Use a dust pan to pick up all dust and debris you sweep off the roof.

3. Remove all objects that are on the roof or in the way of the base sheet where the hot mopping will be applied at. The base sheet is ready to be hot mopped. If it looks like its going to rain do not attempt to hot mop the roof.

4. Put on the face mask and gloves. Turn on the kettle and let it heat up. Drop in the asphalt into the kettle. Let the asphalt melt fully until it gets a watery consistency. Pour the melted asphalt in the bucket and you can hot mop the prepared base sheet.

References

• Advanced Roofing Services Inc: Built-up Hot-Mop Roofing
• Research Roofing: Hot Mopped Roofing