Self-Stick Flat Roofing – What You Need To Know
Granulated self-stick flat roofing, also known as peel-and-stick roofing or self-adhesive roofing, is a type of roofing material that is relatively inexpensive compared to almost all other professional amd long-lasting or durable options. This type of cheap roofing material is typically made of a combination of asphalt and granulated top surfacing, similar to asphalt shingles, which provides a degree of waterproofing and protection against weather elements, in the field of the roll membrane.
The picture below shows an example of a peel-and-stick roof surface on top of a city rowhome. An experienced roofer might catch the difference between a real single-ply roof membrane like a modified bitumen granulated membrane and this type of temporary roof by looking at the edges at overlaps and noticing that the membrane is not the full thickness of a real permanent roof system. However, many home inspectors and building inspectors do not actually get on the roof themselves and or look at rooftop conditions. Also the few inspectors that do look at rooftops themselves often do not know the differences between all of the different types of roofing products on the market today.
Unlike typical single ply flat roof membranes, intended for professional and commercial purposes, often and commonly in Washington DC used on Historic rowhomes, this material is very different period those professional materials are thick and durable, this material, by comparison is lightweight and very thin and similar to a pitch roof shingle, except it is in a roll and slightly more resilient with higher flexible.
The outline of our discussion follows below:
- When self-stick roofing is ok
- Inherent limitations in self-stick roofing
- Why do people still use self-stick for things they shouldn’t
When self-stick roofing is ok
The pragmatic applications for self stick or temporary roofing are very limited, but there are some particular cases where something really short-term that’s a little bit better and more expensive than a tarp is useful and apropos.
Temporary roofing: It can be used as a temporary solution on construction sites or for emergency roof repairs. Its low cost and ease of installation make it a convenient choice in such situations.
Sheds and outbuildings: Granulated self-stick roofing can be suitable for smaller structures like sheds, garages, or outbuildings where aesthetics and longevity may be of lesser importance.
The picture below shows a scene in a software roof system period if you look very closely, you can see that bleed app is missing where it would be found at the lap joint in a typical modified bitumen SBS or even APP membrane. APP membranes typically have less bleed out than SBS modified between the membranes but you can still see the difference when the modified bitumen and single-ply roof membrane is properly installed with a torch welded seam.
So-called “flat” roofs should never really actually be flat, it’s a bit of a misnomer. That little bit of minimum slope is very important, that is why we make a point of disambiguating the detail, even though the industry most often applies the moniker “flat roofing”. These low-slope roofs are almost flat but must technically have at least a very low-slope that ranges from about over 0.25:12 to a pitch of less than 2.5:12. These numbers express the ratio or slope of incline in a roof. The nomenclature is used throughout the roofing industry. In the first exame here, we say the minimum slope is 0.25:12. That means for every 12 inches (or units in any measurement system) of horizontal run, the incline or measurement the roof slopes upwards is 0.25 inches (or units). In this particular case, it’s a very low-slope: only one quarter of inches of rise over 12 inches of run. That’s almost flat. Hence, so-called “flat” roofs can be very close to flat, but the 0.25 units of run allows water to slowly drain away and run off the roof.
The picture below shows a chart of pitch roofs with a description of the roof slope at each respective diagram. You can see that a 1/12 roof is very close to flat, but a 18/12 slope roof is extremely high pitch like A-frame or Tudor style house or building. For context, imagine that the building at the top left corner of the diagram below is 4 times more slope than a minimal amount of slope at a typical flat or low-slope roof.
The picture below shows the exposed edge of a portion of self-stick modified bitumen membrane. You can see that the edge just is laid on top of the substrate membrane and there is no bleed out. Bleed out is emulsion that melts from the underside of modified bitumen membrane. The amount of bleed out is used as a measurement to determine proper melting temperature was reached in the application of modified bitumen membrane.
Inherent limitations in self-stick roofing
It should be understood, by building and home owners, especially in historic flat roof neighborhoods like Dupont Circle and Capitol Hill, that granulated self-stick flat roofing has significant shortcomings and limitations:
- Lifespan: Compared to other roofing materials like metal, tile, or even traditional built-up roofing systems, granulated self-stick roofing tends to have a shorter lifespan. It may last around 10-15 years, depending on the quality of the product and environmental conditions.
- Durability: The adhesive used in self-stick roofing may not have the same durability and longevity as other roofing systems. Extreme weather conditions, such as hail or heavy snow loads, can potentially damage or dislodge the granulated surface.
- Aesthetics: Aesthetics are rarely a concern in flat roofing, but granulated self-stick roofing is not known for its attractive appearance. It may lack the visual appeal of more premium roofing materials and may not be suitable for structures where aesthetics are a significant consideration. However, in most installations, on low-slope roofs, you can’t really see these areas easily.
- Limited application: Self-stick roofing is not typically recommended for high-slope roofs or areas prone to high winds. Its adhesion properties may not be sufficient to withstand the forces experienced in such conditions.
Why people still use self-stick for things they shouldn’t
In an upcoming future article, we’ll talk about the shortcomings inherent in the use of low-durability and temporary materials in long term installations. While a cheapo quick fix can be helpful in some ways at times, sometomes cheap can actually costvway more in the long run. We recommend that before choosing a cheap alternative for flat or low-slope roofing, it’s worthwhile to consider the specific requirements of your project and consult with a professional roofer, like Dupont Roofing, who can advise you on the best roofing solution based on your needs, budget, and the longevity you desire.
The upkeep, maintenance, and general care of flat and mansard roof systems should be driven by an understanding and passion for historical methodologies, waterproofing principles, engineering and building science. Washington DC, a city built with both vintage charm and contemporary modernities, residential and commercial buildings of substantial value.
The roofs of these buildings are their defensive shield from the harsh elements of nature. To our clients, as well as all readers of this article and our blog, we emphasize the importance of quality construction and active building maintenance. Our website includes informative resources you can use to understand and learn about best practices on preservation of your building. If you are in need of further guidance on the roof and its associated systems for your Washington DC property, we are here to assist, where we can. Simply contact us or complete the webform below and drop us a line and we’ll respond if we can help.