Why aren’t plastics used more in roofing?



It’s just that, every couple years, the house needs a new roof due to wear and tear, stuff falling on it, etc.; fine, I get it. Meanwhile, the Playskool house across the street in the neighbor’s yard has been there, taking similar kinds of abuse long enough for the original kids who played in it to have kids of their own, and not one leak.

Seems like a simple enough solution, and I’m nowhere near smart enough to think no one else has thought of this, so what gives?

In: Other

Plastics have a high thermal expansion rate but more importantly most plastics that I’m aware of degrade faster than traditional materials when exposed to uv light. Since a roof is pretty much always exposed uv light this would mean that plastic tiles would be less durable than normal asphalt shingles.

They kind of have plastic roofs you can buy. Some people have concerns about how on the strips lock together without gaps and their longevity over time. Getting a 25 year or even 50 year warranty from a reputable company using standard GAF materials is pretty standard. I’m not really sure if PVC can last that long.

There are also issues with work crews knowing how to work with plastic and city codes. And finally if you go to sell the house and have a nonstandard roof, potential buyers might be a little scared.

Your house needs a new roof every few years? Ive been living in a very old house with an old roof for 15 years now and the roof has never been touched

Is this something only americans can relate? We dont have shingles where i live and roofs lasts for a generation

Plastic is not good in a fire scenario, it melts and can trap people.

A very famous case of this happened in Isle of Man where 50 people were killed and over 80 injured. ( [https://en.wikipedia.org/wiki/Summerland_disaster](https://en.wikipedia.org/wiki/Summerland_disaster) ) As a result, Isle of Man have their own very stringent fire regulations in Building Codes.

One of the reasons they make polyethylene (PE) sheeting black is that “carbon black” (pretty much powdered carbon) is one of the best things for protecting it against UV degradation, which is the breaking of the long chains (i.e. why it called Poly) and making it brittle.

So yes, one of the few things that affects PE is UV radiation, so it’s not particularly good for outside use. Same for polypropylene.