Oklahoma City, OK
Are Roof Shingles Toxic?
The toxicity of the materials used for roof shingles has become a valid concern for homeowners, particularly in the wake of asbestos removal programs that have demonstrated how harmful building materials can be. But, are roofing shingles toxic at all?
The primary contaminant of concern in modern roof shingles is the petroleum-based products used to manufacture asphalt shingles. These shingles have been shown to release dissolved organic carbon, which can interfere with rainwater collection activities.
However, this problem can be easily combated with a simple water treatment system if you are trying to get potable water out of your rainwater collection system. In this article, we will focus on safely installing and removing roofing materials, specifically old shingles made from materials considered more toxic than modern alternatives.
Are Roof Shingles Toxic?
Modern shingles can be toxic during installation, but they will usually not be harmful unless you’re trying to collect potable rainwater from the roof; chemical constituents in the shingles can find their way into the run-off water.
Other than that, shingles themselves are not necessarily toxic per se. The most significant health hazard from any modern roof shingle is the dust that may be stirred up during the removal process.
Roof shingles are made from a variety of materials, but most shingles used today are asphalt-based. There are several different types of roof shingles:
- Organic Asphalt Shingles
- Fiberglass Asphalt Shingles
- Metal Shingles
- Plastic or Rubber Composite Shingles
- Fiber Cement Shingles
Asphalt shingles are the most commonly used roofing material in the United States. They contain underlayment that consist of fiberglass or polyester; the asphalt may be modified with a polymer or a polymeric coating. Pre-existing homes, particularly those that have not had their roofs replaced in a while, likely contain fiberglass-based asphalt shingles.
Which Roof Shingles Are the Most Toxic?
Asphalt-based shingles are only harmful during the installation and removal process, where roofing workers may encounter construction dust and sealants; this is mainly the case with heated asphalt that may still be used in the construction of commercial buildings.
Other kinds of shingles may pose similar risks during construction, although a few varieties have been known to pose different types of dangers:
- Cedar shakes shingles carry some natural insulative properties and may even be recycled for mulch at the end of their life cycle. The downside is that they have to be treated with fire retardants; these chemicals can be toxic to the point of negating their non-pollutant status to some degree.
- Historically, asbestos materials were used in some types of shingles. These would pose the most significant health hazard due to the damage that fibers can cause to the lungs if the shingles are broken. (More on asbestos shingles later.)
If you are removing old roof shingles from a home, you should be advised that they could be harmful; this is especially the case for shingles containing asbestos. With that said, make sure there is no asbestos in the roof if you are looking to replace shingles dating back to the 1970s.
Asbestos-cement shingles were in use from the 1930s until the 1970s, at which point they were banned. It was once a premium building material due to its durability and fire-resistant properties.
Asbestos becomes hazardous to human health when the materials begin to break down and become airborne; in this form, the mineral is regarded as a carcinogen. The fibers accumulate primarily in and around the lungs; as an example of how asbestos can affect the body, former asbestos workers often suffer from scarred lungs.
Luckily, the shingles do not become a hazard until they have begun to break down, releasing the hazardous fibers. However, due to the potential dangers of handling the material, local regulations may require you to hire a contractor who is qualified to remove materials containing asbestos.
Checking for Asbestos
If you are unsure of whether your roof is made of dangerous asbestos materials, you can always collect a sample from the shingle material to get tested. This handout from the Maryland Department of The Environment provides guidance for determining your roof’s asbestos content.
You certainly do not want to go into a OKC roofing remodel project, unsure of whether your roof contains asbestos or not. It has been many decades since the 1970s when these materials were initially banned, but there is a slight chance that vintage home renovation projects could still require removing such materials.
How Do I Safely Install Roof Shingles?
The roof shingle installation process is not exceptionally dangerous by any means. Still, there are steps that can be taken to ensure that the process does not become harmful for residents.
Asphalt shingles do not really become toxic until hot asphalt is used during the installation process. Hot asphalt is the most hazardous material used during roofing activities, and they are really only used during the construction of commercial building roofs.
Safety tips for working with hot asphalt during the roofing process include:
- Wearing clothes that are made of natural fibers, rather than synthetic fibers that can melt
- Wearing work gloves with snug knit cuffs, safety glasses, and boots with thick rubber or composite soles
- Air intakes and ventilators should be covered so that the potentially-harmful asphalt fumes are not allowed to enter the building’s interior
As far as residential installations go, you will likely not have to deal with hot asphalt fumes. Modern residential roof construction generally does not involve the use of toxic chemicals. Any hazards will typically only be encountered by the workers installing the shingles, not the home’s residents.
One of the most significant hazards is associated with the placement of the white single-ply membrane used during the construction of “cool roofs.” While these roofs do accomplish the task of making the home energy-efficient, they involve the use of highly flammable solvents and adhesives to secure the roofing materials.
A crisis can be averted if workers wear protective clothing and equipment, as recommended above. After the installation process is done and over with, these materials do not pose a significant health hazard to residents in the same way they do for the workers installing the shingles.
You may be able to send asphalt shingles off to a recycling center to dispose of them safely. These removed shingles are ultimately valuable for use in the production of hot mix asphalt used on driving surfaces. Disposing of asphalt shingles in this matter ensures that landfill space is conserved. It also helps to reduce the number of new materials needed to complete road construction projects.
You can find your local shingle recycling center on this website developed in conjunction with the Environmental Protection Agency (EPA). You are strongly encouraged to contact the recycling centers near you before committing to a specific project plan. Policies vary among recycling centers, with some taking asphalt shingles donations for free while others charge a fee.
Landfill and Waste Disposal
If the shingles are not recyclable, you will have no choice but to have them taken to a landfill. When shingles are removed, homeowners usually contact a waste management company to let them rent out a roll-off dumpster. Make sure that you get one large enough so that you won’t have roofing materials spilling over into your yard.
If you want to keep dust and run-off to a minimum, then you are encouraged to look for a dumpster that has a cover over it when it’s not in use. This can help minimize dust during roofing renovation projects.
The construction dust represents the most significant hazard during the roof shingle removal process. Those with upper respiratory issues should certainly consider which type of dumpster they decide to have the old shingles put in.
Concern about the toxicity of shingle materials goes well beyond the impact that they have on human health. Homeowners also want to be sure that they choose roofing materials that won’t have too much of a negative impact on the environment.
- Fiberglass and organic asphalt shingles would not necessarily be considered materials that hit high marks in sustainability. These shingles are primarily composed of petroleum-based products with very little recycled content.
- Fiber-cement shingles have a detrimental impact on the environment during the manufacturing process, contributing to air and water pollution. However, they are much more durable than other types of shingles, lasting as long as 25 years before needing to be replaced.
- According to the University of Tennessee, composite shingles made of petroleum-based asphalt are the least environmentally-friendly roofing materials. Fortunately, these tiles are now frequently recycled for use in road construction and other similar projects once they are removed from residential roofs.
- Metal roofing is known to generally last longer than asphalt shingles while also weighing less. As mentioned earlier, this type of roofing material is also better for use in rainwater collection systems where you plan to use the collected water supply as a source of potable water.
- Wood shingles sourced from sustainably-harvested timber can also be a safer and more environmentally-friendly roofing option than traditional roofing materials like asphalt shingles.
Roof Water Run-Off and Toxic Materials
As mentioned earlier, asphalt shingles themselves are not particularly harmful. Most residential housing applications don’t involve the use of heated asphalt, which can lead to short-term illness during the construction process of commercial roofs.
However, fiberglass-based asphalt shingles do become a concern for those who are collecting rainwater. It’s not a problem to use this supply to water plants, but once you start drinking it, it becomes a hazard.
According to research from the University of Texas, harvested rainwater from asphalt fiberglass shingles and “green” roofs can contain high amounts of dissolved organic carbon (DOC). Water with high concentrations of DOC becomes hazardous to human health when it is mixed with chlorine, a product frequently used to disinfect water.
Toxic Metals in Run-Off
One of the leading causes of concern in the past has been the presence of potentially toxic metals in storm run-off from roofing materials. Newer shingles have been found to be less harmful than their predecessors in this regard.
Metals of concern include:
Research performed at the Washington Department of Ecology has shown new roofing materials generally release low concentrations of metals, with the exceptions being:
- Copper and arsenic from treated wood panels
- Copper from copper panel shingles
- Zinc from EPDM (rubber) roofing
The rainwater collection study at the University of Texas revealed which types of roofing materials would be suitable for collecting potable water. (Understandably, most homeowners are not going to switch their roof just for rainwater collection, but it is a worthy topic of discussion for those who are in the market for a brand new roof.)
The following roofing materials contribute the least amount of pollutants into the rainwater, according to the study:
- Galvanized steel metal roofing (specifically Galvalume in the study)
- Concrete tile
- Cool roof shingles (These are light-colored shingles specifically designed to reflect solar radiation.)
If dissolved organic carbon (DOC) is the primary contaminant, then you may still consider using the run-off as a potable water source, provided that you do not use chlorine to disinfect the water. This applies to run-off from roofs containing asphalt fiberglass shingles and green roofs with plants.
If you are going to disinfect rainwater run-off from asphalt fiberglass shingles, you are highly encouraged to use a technique that doesn’t involve chlorine. This chemical creates a harmful by-product when it is combined with dissolved carbon from the roofing material.
Treatment with either ozone or ultraviolet light should be adequate alternative methods for making the collected rainwater safe for potable use, such as drinking water. If the rainwater is only being used to water your garden, this step will not be necessary.
- Although ozone is an effective treatment method, it is not necessarily best for residential use due to the presence of toxic gas. Ultraviolet light should be the go-to disinfection option if you are concerned about the dangerous combination of dissolved carbon and chlorine.
- UV light is effective against common forms of bacteria, with the downside being that it doesn’t work its way through the water supply in the same way that chlorine does.
Here are some tips for installing a UV-light treatment system at the end of your rainwater collection system:
- Install a water filtration cartridge ahead of your UV-light. UV-light treatment is only effective if the water is relatively clear. Even an RV Water Filter can help remove enough sediment, though you may have to spring for a more advanced system if you plan on drinking the water.
- Look for a UV-treatment system that meets ANSI/NSF Standard 55 testing requirements, including being fitted with a system that alerts you if cleaning is needed or the lamp needs to be replaced. (Note: The BluOnics Filter System has these features.)
Are Other Roof Components Toxic?
Of course, there’s also the question of whether other roofing components, such as the sealants and chemical treatments used on roofs, are toxic as well.
Are Roofing Sealants Toxic?
The sealants used to attach the shingles to the roof may be hazardous to human health. Special precautions must be taken by workers to ensure that these normally-benign products do not become harmful due to careless use. Once the installation process is over, these chemicals are no longer concerning.
Are Chemical Roof Treatments Toxic?
The chemicals used for moss control on shingles can potentially be harmful if they are not used properly. Zinc strips are commonly used to control the growth of moss on top of roof shingles. These materials are effective at killing or reducing the growth of mosses and fungi on roof shingles.
The primary hazard posed by zinc strips has to do with the effects of rainwater run-off. The zinc can find its way into the run-off, where it can have a detrimental impact on the plants and trees you are trying to grow in your yard. You are certainly encouraged to use zinc strips responsibly and physically remove moss when possible rather than rely on chemicals.
It has also been suggested that soap-based products are safer than other chemicals and still effective at holding off moss and algae. One such product is Safer Brand Moss And Algae Killer. This is a multi-use product that can be sprayed on decks, fences, roofs, and lawns to control algae and moss growth.
Roof shingles, in their current state affixed to your home, are not particularly hazardous. The most significant cause for concern would be collecting rainwater as a potable water source inside the house. In this event, you would be strongly encouraged to use a water treatment method other than chlorine to disinfect the water; this is due to the dissolved organic carbon content in run-off water from asphalt shingles.
Careful steps should be taken during the removal and installation of roof shingles, where construction dust may become a prevalent problem. You may also consider testing your roof shingles for asbestos, especially if you are restoring an old home where the roof hasn’t been touched in several decades.