Should You Repair Or Replace Alligatored Built-Up Roofing?
Built-up roofing (BUR) has been protecting commercial buildings with flat roofs for decades and is still prized for its durability. Unfortunately, years of exposure to the elements will take their toll on any flat roofing material, and many built-up roofs used on commercial properties suffer from a type of damage known as 'alligatoring'.
What Is Alligatoring On Built-Up Roofing?
A well-constructed built-up roof is completely watertight and highly resistant to wind and rain, but sunlight is the arch-enemy of any commercial flat roofing system. Because flat roofs are not pitched, they are constantly exposed to intense sunlight for most of the day, even when the sun is relatively low in the sky.
After years of use, this continuous exposure to UV light can degrade the top, visible layer of asphalt on a built-up roof. A layer of roof ballast, such as gravel, can provide a certain amount of protection, but UV rays will still penetrate and cause gradual damage.
This sun damage reduces the binding effect of the bitumen contained within the asphalt, and the asphalt will start to crack apart. These cracks will be small and superficial at first, but become deeper and more widespread over time.
Your building's roof is more vulnerable to cracking if your business is located in an area with a wide variance in day/night temperatures. The roof will expand slightly during the hot days, and contract during the cold nights, pulling the sides of each crack apart little by little.
Alligatoring occurs when large numbers of cracks start to intersect, creating a pattern of cracks very similar in appearance to an alligator's scales. As you can imagine, dense webs of cracks are bad news for any built-up roof. Once alligatoring becomes severe, the roof can lose its water tightness and start to leak.
Should You Repair Or Replace Alligatored Built-Up Roofing?
Most flat roofing materials used on commercial buildings, including BUR alternatives such as single-ply membranes, can suffer from alligatoring, and it is generally seen as an inevitable consequence of age. Proper maintenance of your building's roof, including regular resealing, will help to delay it for as long as possible, but most flat roofs will fall victim to alligatoring at some point.
If alligatoring is restricted to small, isolated patches of your building's built-up roof, it may be possible to repair them and extend the life of the roof by years. Slight cracking can sometimes be filled in using a stabilizing, polyurethane-based sealant, but in most cases, the affected patches will need to be cut out and replaced with new asphalt and ply sheeting.
If alligatoring has spread across most of your roof, or the cracks have become deep enough to cause leakage, replacing the roof entirely is usually the only viable option. The roof can be replaced with new BUR, or you can switch to TPO membranes or other alternatives.
If your building's BUR roof is suffering from minor or severe alligatoring, you should call in a professional commercial flat roofing repair contractor to examine the damage and recommend a suitable course of action. If you choose replacement over repairs, your contractor can recommend the best replacement materials for your building's needs.
To find out more, contact a company like JWF Roofing.