Hey Vern,
It’s a hot one! I am looking for ways to cut back on our AC bill while still keeping the house cool.
When I brought this up to my neighbor, he said he used a “cool roof coating” on his garage. It’s a white paint coating he put on last summer and says it’s working. Now, I’m not one to get out the ladder for something like that unless it really pays off. So my question is:
Can you really paint shingles white to keep your house cool? Is this something I can use on my house- or is it just for garages/sheds/etc?
Thanks,
Dale from Tamaqua, PA
Dale, I’m glad you reached out before stopping by the hardware store. While I can’t inform you too much on the state of your neighbor’s roof, I can tell you this is NOT the answer for the asphalt shingle roof of your own home.
Painting anything on your shingles is a bad idea: let me tell you why.
This coating is a type of paint known as elastomeric. The paint was designed in the 1950’s but the practice of using it on roofs has grown more prevalent in recent years. In fact, in some misguided circumstances even authorities have encouraged the use of this product to try to make roofs more “energy efficient”. In 2010, Florida Power and Light reimbursed contractors who painted roofs with elastomeric coating… only to be sued when the roof’s started leaking as a result.
The white coating is believed to protect against water damage and reflect UV rays to keep your roof cool. But much like layering shingles, it causes more harm than good.
Let’s take a look at the potential threat it poses to your roof.
Do Elastomeric Coatings Help or Hurt Your Roof?
Do elastomeric coatings decrease energy bills?
Yes…and no.
In the summer, the coating can decrease energy costs.
But what you’re saving in the summer, you’re repaying in the winter. The coating affects heat absorption on cold days. Even more, when your roof can’t regulate heat you increase the risk of ice dams.
More bad news if you live in a rainy place like Schuylkill County: Roofs painted with “cool paint” are more susceptible to moisture damage. Mold and algae grow on top of the coating, as well as inside and under when the coating cracks.
Still considering painting your roof white? Here’s the big reason to stay far away from this product: Elastomeric coating is known for voiding manufacturer’s warranties and insurance claims against early roof failure.
All this adds up to a weakened roof and a lot of potential out-of-pocket expense for you.
Other downsides to the coating include:
- Decrease in curb appeal
- It locks in dirt and contaminants
- Requires regular maintenance and yearly re-application
Don’t do it, Dale! If your HVAC is struggling to keep up and you think your roof’s temperature is to blame, let’s check your ventilation sizing instead.
Overheating Roof? A Job for Attic Ventilation
The most important parts of a home’s structure are the unsung heroes we never see. Soffit and fascia keeps bugs and rodents out of your attic. Your home’s foundation keeps water from flooding your basement. And your attic ventilation? It regulates your home temperature.
More times than not, we don’t think of these systems until there’s a problem. Dale, if your home is unable to regulate its internal temperature? There’s a problem.
So what is attic ventilation? And how does it work?
Ventilation works by utilizing one of two systems: passive and active. Both are based on the fact that heat rises. Passive ventilation uses convection to cool your home. The intake vents pull cool air into your attic, while the exhaust vents on your roof’s ridge filter the air out.
Active ventilation does the same thing but utilizes powered fans and vents to get the air moving.
When you ventilation is sized correctly to your home, it:
- Protects it against mold and mildew
- Increases your home’s indoor air quality
- And keeps your shingles at peak performance for longer
Interested in learning more about your ventilation system? Our previous article offers a further breakdown on how ventilation works and the benefits of the system.
You might be thinking “My roof already has vents- that can’t be the solution.” And, you may be right. But more often than not? I’ve noticed many roofing installers don’t size ventilation appropriately to the structure’s build, age, and sun exposure.
Good news: You may be just a vent or two away from the comfort you’re looking for!
Ready to Safely Keep Your Home’s Roof Cool?
Dale, I’m so glad you reached out about this! Not enough homeowners know about the danger of “cool roof” or elastomeric coatings when applied to shingle roofing.
Give me a call at 570-345-0436 when you get a chance. Let’s assess your home and learn what’s really going on with your roof.
Until next time,
Vern Martin
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