Is This Roof Material a Gimmick? Good for the Environment?
So is synthetic underlayment really all it's cracked up to be, or is it just another underlayment gimmick? Well, back in the day, there used to be only two types of underlayment - 15 pound and 30 pound. As manufacturers started to lighten these products up, they tried to pull a fast one on us.
They took the little pound symbol "#" that used to denote the weight and put it in front of the number. So now it's number 15 or number 30 felt. Fast forward a few years and synthetic felt enters the market. Now, this product is being touted by everyone as the greatest thing since sliced bread.
As an installer, I like it. It's easier to handle, lighter weight, and doesn't tear as easily. But it's expensive and made of plastic. We all remember what plastic is, right? Superheated oil that never decomposes. Every roof we install gets recycled, except the plastic has to be removed first.
Then it goes through grinders and gets turned into basically pavement for roads. But those grinders can't handle plastic. So I'm afraid every roof I install today with synthetic underlayment will be disqualified from recycling in the future. I'll have a real problem with that.
Bottom line - make up your own mind. The jury's still out. But don't listen to anyone with a financial stake in it. See you next time.
Researching Roofing Underlayment
According to IKO, the numbers 15 and 30 used to represent the weight in pounds per hundred square feet, but over time, the actual weights of the products have changed significantly. For instance, #15 felt papers are now about 8.0 pounds, while #30 are around 16 pounds[2]
According to Owens Corning, synthetic underlayment has several advantages over felt underlayment, such as being more durable, tear-resistant, moisture-resistant, and lighter[1]. According to GAF, synthetic underlayment can also be left exposed for longer periods of time and has a higher fire rating than felt[3]
According to IKO, synthetic underlayment can cost more than felt underlayment, depending on the brand and quality[2]. According to Owens Corning, synthetic underlayment is made from materials like polypropylene or polyester[1], which are types of plastic.
According to GAF, asphalt shingles can be recycled into new shingles or other products like asphalt paving[3]. According to Earth911, there are many recycling centers that accept asphalt shingles with synthetic underlayment. However, some recyclers may charge a higher fee or require a higher purity level for shingles with synthetic underlayment than those with felt underlayment.
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