Ultraviolet Damages Roofs – PART II

Learn why ultraviolet damages roof in this two-part series guide

In a recent article we took a look at the harmful effects of ultraviolet rays and deterioration at flat roof systems from exposure to sunlight.   In this article, we take a closer look at the same type of deterioration but as it affects different types of building materials of other roof systems. We explained the harmful effects of ultraviolet rays cause damage and essentially disintegrate every roof membrane type, over time.

Roof Coatings and Improper Asphaltic Patch Material Types

In the picture below we show examples of types of roof coatings and improper types of asphaltic patch material or petroleum based type coatings which are ineffective to resist ultraviolet rays when used alone without a final reflective coat. intended to reflect and resist the harmful effects of sunlight.

In the first part of this series, we showed uncoated roof systems of modified bitumen smooth membranes. The system in the photo below is also a modified bitumen smooth membrane. This particular type happens to be a APP modified bitumen flat roof membrane.  It was coincidentally installed around the same time frame. However, there’s a major difference between this roof system because this particular roof system has a high reflectivity white elastomeric coating application.    This particular coating application was applied over three years ago, And the coating has not been cleaned since the time of application. Cleaning with a low power pressure washer is easy to do and helps improve reflectivity, but nonetheless, this membrane is largely protected from some of the most damaging types of exposure.

asphalt material types ultraviot damages roof

The picture below shows a different roof. This particular roof had multiple different repairs done in different ways, obviously by different contractors who had varying degrees of understanding of building science and roofing systems.

An asphaltic type patch or seal material was used. This type of material is not appropriate to be used with this type of system.  This type.of patching material is really intended for built-up roofs which have a ballast or aggregate applied after repairs or initial installation. Instead, since this is a modified bitumen roof the materials can bond to one another to a degree, but this type of material applied, here, does a poor job to protect the modified bitumen, as you can see the material itself has deteriorated significantly since the time of application.  

This particular picture focuses on a transition area between a fiber modified aluminum coating on top of a ceramic granule covered modify bitumen membrane. Ceramic granule covered modified bitumen membranes do not need to be coated, but often building owners or homeowners do not know and or misunderstand the requirements for upkeep and maintenance and contractors are either unaware themselves or misrepresent the nature of the materials to the clients. This type of coating was never intended or necessary at this location.

asphaltic type material roof

Inappropriate Material Type For This Type Of Application

The next picture focuses on the same roof, but just at the asphalt repair area and you can see the significant texture on the surface of the coating as a result of deterioration from exposure to ultraviolet rays.

asphalt repair area

Low quality contractors often leave their used materials or trash scattered throughout a roof because they just don’t take the time or effort to work conscientiously. In this case the contractor or workers left the bucket of material right there next to the area of repair.   Interestingly, almost comically, the material packaging, on in the label on the bucket, explains that this type of material is not appropriate for this type of application.

inappropriate material type for roof

At another limited spot, you can see where a thicker trowel grade type of asphalt patch material has been used without any type of fabric reinforcement. Thick applications of asphaltic patch material will invariably deteriorate and crack without reinforcement, unless specifically made to be self supporting.

trowel grade type of asphalt patch

How To Maintain Your Roof

Smart proactive replacement, construction, upkeep and maintenance of low slope roof systems requires an enthusiastic interest and understanding of waterproofing principles and building science.   Here in Washington DC, historic and modern residential and commercial buildings are extremely expensive and the roof and related systems provide the shield that preserves the building. 

We encourage all of our clients, and all readers of this article and to our blog in general, to prioritize the value of quality construction and building maintenance, and develop a relationship with our company.  You can learn a lot more on our blog.  Feel free to check it out.  If you have questions about the roof and related systems of your building in Washington DC, contact us or fill out the webform below and drop us a line.  We will be in touch if we can help.

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