Q & A - What is Alligatoring?

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July 29, 2013 at 12:00 a.m.

Roof alligatoring occurs when a modified bituminous roof surface is cracking.

What is this picture of?

Is it a picture of:

  • A very dirty window
  • Desert Mud
  • Leather
  • The chocolate cake left out in the sun

None of the above.

Looking at this unique photo it is hard to know what exactly it is if you are not a roofer. Most of you must have known, it had to be roof-related since we are on a website regarding roofing. So let me describe the photo. It is a part of a roof that has lost its coating of protection or never had it.

This is a photo of a roof alligatoring and is where a modified bituminous roof surface is cracking or sometimes called checking. The roof coating on any asphaltic roof, after a few years, will wear off, and if left unprotected can develop a random pattern of cracks similar to an alligator’s skin. Thus the name alligatoring. The cracks or alligatoring may have different depths and over the years, if left unattended, can even extend completely through the bitumen and into the reinforced mat.

Alligatoring is caused by the suns UV rays drying out any type of exposed asphaltic roofs. If this is left unattended the checking can reach depths into the membrane and damage the roofing system beyond repair. Complete roof failure means a new roof so this is important to maintain low sloped roofs like this with a coating that is compatible with the roofing. These protective coatings can be applied by spraying, rolling or brushing and reflect the harmful UV { ultraviolet } rays. Not only will it keep your roof protected from further alligatoring, but it can also reduce heat and keep the building cooler.

It is advised to yearly inspect any BUR or torch down roofing system and maintenance is given as needed.

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