Tarp sealants, like the plastic roof shingle, are a common way to protect homes from mold.
And while they’re effective, they don’t last as long as you might think.
“There are many problems with the use of these products, and we’re not talking about a single problem that affects millions of homeowners,” says Peter Wylie, a research associate at the Centre for Home Science and Environment at the University of Melbourne.
“A large proportion of homeowners who use them are not aware that they’re not actually good for them.”
Here are five problems with roof sealant use.
They’re not effective enough The plastic roof sealings sold at most stores aren’t exactly high-quality.
There are cheaper alternatives, like “soft sealants” that are less expensive but don’t work well, or “hard sealants”, which are harder to apply.
But you won’t find them at the grocery store unless you go to a store that carries them.
They aren’t waterproof When it comes to roof shings, there are no standards for waterproofness.
And there’s no clear rule for when the coatings should be removed.
Some roof sealers have been found to be “permanent” in the water, meaning they can last for years without being replaced.
So while they can work for some homeowners, they’re unlikely to last as many as you’d think.
They don’t help with mildew When you use a sealant, it works to kill the fungus, so if you get mold, it’s more likely to grow back.
But the same product can also cause mold growth in the same spots where it was applied, which can lead to mildew or other problems.
They leave a sticky residue The plastic shingle is one of the most commonly used roof shinging products on the market, but the residue left on the floor and in your kitchen is not what you want to see on your roof.
“You’re essentially washing your floor in that sealant,” says Wylies.
They make your home look worse It’s a common misconception that sealants will keep your home looking nicer, but that’s not always the case.
“I would suggest not using the same type of sealant for the same application,” says Dr. Paul D’Souza, a professor of environmental microbiology and microbial disease at the Institute of Food Technologists at the Royal Veterinary College.
He points out that sealings used in indoor air conditioning systems often contain chemicals that are also harmful to the environment.
That includes polychlorinated biphenyls, or PCBs, a chemical that is found in paint.
In fact, the chemical has been linked to cancer in animals, according to the National Toxicology Program.
“It’s not the smell of the sealant that is bad, it is the fact that it’s applied to the surface of the house,” he says.
D’ Souza says there are ways to improve the way you apply sealants.
“For instance, if you have a good sealant with a thin film on the top and it’s not clear, use a thinner sealant or apply the sealer on a piece of glass and the seal is easier to apply,” he suggests.
But for most homeowners, the most important thing is to stick with the products that are safe for your home, he says, because you can’t control how long they last.
And if you decide to stop using sealants altogether, you can always try a different type of shingle.
For example, if a sealer is causing your roof to sag, it may be best to go for something that is more durable and less likely to stick to the floor.