
How do you know if your existing roof is Coal Tar Pitch?
- First, if you have gravel embedded in an asphalt-like substance, this means you have either an asphalt built-up roof or a Coal Tar Pitch roof, now just determine the difference.
- A Coal Tar Pitch roof will usually have lots of small black bumps where the Coal Tar expands on a hot day and bubbles up. A built-up roof can have these too, but less prevalent. On a hot day, some of the bumps will have a shine where they have opened up due to flow.
- A Coal Tar Pitch roof will also have several areas where you can see it has flowed over or around the gravel.
- Pitch dams will be installed at drains and scuppers. These are saw-toothed metal guards designed to let water through, but minimize the flow of the Coal Tar Pitch. Built-up roofs can have these too, but less likely.
- You may have flow down the side of the building, over the edge and heavily into drains.
- You can distinguish by smelling it, if you have experience to know the difference between asphalt and Coal Tar Pitch.
- You can call an experienced roofer who can identify it.