Commercial Roofing Article of the Month

Alternative built up roof repair methods
​Basic repairs can be easily performed on built up roofs using the established standard three course method.  Spud the roof, then apply a layer of asphalt, a layer of fabric, and another layer of asphalt.  This method is applicable the vast majority of the time.  There are a couple of times when years of roofing experience can give you some alternatives.

Embedded gravel.  Spudding on most built up roofs will take you down to the felt level so you have a clean flat surface to repair on.  Occasionally, you will find that all the gravel will not come back up due to materials previously used in repairs or the original installation process.  When that happens, standard cold applied roofing asphalt may not be able to penetrate to the roof surface and give you a watertight bond.  The solution is to spud, brush, apply the base course of asphalt and fabric as you typically would for a standard three course repair.  The difference comes in on the third course.  A horizontal grade modified bitumen adhesive can be used.  The trick is to allow the adhesive to go over the edge of your first course and flow into the gravel that couldn't be removed by spudding.  The thinner consistency of the adhesive will reach through the gravel and bond to the roof giving you a watertight seal.

Alligatoring.  Alligatoring is when the surface of a built up roof starts to crack and resembles the scales on an alligator.  The problem with performing a simple three course repair over this type of problem is the alligatoring will continue under the repair and later reappear around the edges.  A good solution here is to use a cold applied modified bitumen cap sheet.  This sheet can be applied by spudding the roof and applying a layer of asphalt over the damaged area.  Then place the cap sheet over your asphalt and using a heavy metal roller, roll the cap sheet to fully imbed it into the asphalt.  Finish your repair with a three course application around all sides and seams to reduce the possibility of fish mouths forming.

Each repair is different.  If you are ever unsure about how to address a repair, it is always best to call in a professional commercial roofer.  Using the wrong materials or methods will always give you, at best, unsatisfying results and at worst, further damage your roof.


  • Full service commercial roofing contractor

  • Service all flat and low slope roof types

  • Install rooftop wind turbine systems

  • Install skylights other types of roof penetrations

  • Install green roof systems

  • Seal and waterproof leaky HVAC systems

  • Develop long term roof maintenance programs

  • Most importantly, we make your job easier by removing the burden of roof care off your shoulders.

What we do?

For a commercial, industrial, or institutional building owner, the roof of your building is one of the most critical elements of your property management programs.  With clients occupying those spaces, or potentially millions of dollars worth of equipment inside your property, a leaky roof cannot be tolerated.  Controlling the cost of your roofing programs, while maintaining the integrity and full lifespan of your investment, must be a top priority.  The problem many seem to face is how to deal with all the different types of roofs they may be responsible to maintain.  When a manager oversees buildings roofed with a variety of materials, such as BUR, single ply (EPDM, TPO, PVC, etc), metal, modified bitumen, and low rise foam, it can be difficult to know how to deal with each roof type, if you are not a professional roofing contractor.  That is when having a partner who will work with you, with your best intentions in mind, is absolutely critical.  


At ISR, our team will work with you to maximize the useful life of your roofing systems.  Covering all of western North Carolina and southwestern Virginia, we are ready to respond to any roof leaks you may encounter or set up a long term roof management program to extend the life of your existing flat or low slope roof system.

Ensuring a Reliable Roof for Your Business

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