The Second Step in The Re-Roofing Process – Hot Mop

Roof Replacement

re-roofing process

Due to the everchanging and harsh weather conditions of South Florida, your roof will require maintenance and ultimately go through a re-roofing process at least once or twice in your lifespan. Part of the process is the hot mop stage. This helps to ensure that no leaks or roof damage occurs and requires a material called modified bitumen. Bitumen can be used on either sloped or flat roof decks and is installed through the “hot mop” process, but what is a “hot mop” in progress?

Applying the hot mop in progress is the second step to a general re-roofing process, acting as a secondary barrier between dry materials and tiles. It serves to protect the base sheet on your roof and keep it watertight. To begin the hot mop process, a layer of hot asphalt will be spread on top of the roof’s base sheet. The hot asphalt is laid out evenly with a large, heated mop over the surface. At the same time, A 90LB felt or modified bitumen cap sheet (which is a type of asphalt that is modified with rubber or fiber) is applied onto the hot asphalt.

Once these two layers are imbedded simultaneously, they are then back-nailed to secure them onto the roof, covered by the following ply (a kind of synthetic ‘membrane’). There are different types of material that can be used for flat and sloped roofs with the hot mop process:

  • Flat Roofs: When reroofing a flat roof, a mineral-surfaced cap sheet or a commercial grade modified bitumen can be used. These two materials would both be simultaneously applied with the hot asphalt (tar), or Torch Applied with a flame torch. The torching method involves a flame torch that used to heat up the bitumen material as it is layered onto the roof in order to melt it and secure it tightly onto the base sheet.
  • Sloped Roofs: You would normally hot mop with either the felt or granulated modified bitumen. If this method is not preferred for whatever reason, then there is an option to use a Peel and Stick; which is a self-adhered material to be modified on sloped roofing.

With the use of any material, the hot mop process is generally very complicated, and so the duration of this process may be timely, depending on the pitch and total square footage of the roof. The equipment required includes the asphalt, the preferred material (mineral surfaced cap sheet or commercial grade modified bitumen etc), a tar kettle, propane, lugger, mop buckets, ropes mops and fire extinguishers. Professional roofing contractors will wear safety gear, such as protective eyewear and heavy-duty gloves.

Unfortunately, hot mopping expels strong and noxious fumes, and so customers may be asked to leave the home so that the tar can be safely applied onto the roof. The fumes are not extremely toxic, but it can pose a risk for any children, elderly or people who suffer from breathing impairments such as Asthma. If any mess occurs during the process, it will be taken care of! Ply wood and tarps are often used to cover surrounding areas such as driveways, patios, or lawns. After the process has been completed, ABC Roofing will make sure that no materials go to waste, and any left-over tar will be used with new sticks of asphalt for the next re-roofing job!

The roofers at ABC Roofing Corp have been servicing South Florida roofs for over 30 years. Licensed and State certified we are proud of our reputation as an honest and loyal company, and are commitment to excellent service and satisfying our customers every need.


The second step in the re-roofing process – the hot mop – is an essential part of a tile roof system. It protects your base sheet and keeps your roof watertight by acting like a secondary water barrier between the dry-in materials and the tiles.

On a sloped roof, hot mopping begins by embedding a 90Lb felt or modified bitumen cap sheet in hot asphalt. The material is back-nailed to secure it to the roof and covered by the following ply. On a flat roof, a mineral surfaced cap sheet or a commercial grade modified bitumen is used and can be torch applied or layered with hot asphalt.

The duration of the hot mop in progress depends on the size and pitch of the roof. And because the fumes are noxious and unpleasant, it is best for all occupants to leave their home for the day.

Although this is a messy job, every precaution is taken to protect your property by laying down plywood and tarps. Should the rare mess occur, the area will be pressure washed, immediately, with the appropriate cleaners.

Follow the next step in the roof installation process – Tile Install – to see how your new roof starts to take its final form. Visit our website for more information because at ABC Roofing have you covered.

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