The Battle of Sealer VS The Elements

The Scenario:

It’s Saturday morning as you stroll to the mailbox in your robe, coffee in hand, looking to grab the mail that the postman just dropped off. You notice on your walk the asphalt sealant on your driveway you just had done the previous fall is already starting to wear off in certain areas. You may think to yourself, “What the heck?! It’s only been eight months since this was done!” You are not alone in experiencing the wearing down of sealant that may not be that old. Was it the snow plow? Was it the snow blower? Did the company miss a spot? Could it have been the large maple tree? Was I warned about this?

These are all valid questions running through your head. While every driveway is different in the way that it cures its sealer, we’re here to explain more on why these situations may happen. Keep in mind that sealer is supposed to wear away over time, which is why we recommend maintenance every two to three years.

Mother Nature

Due to the main ingredient being water, required by Dane County specifications, the sealer we use requires direct sunlight and heat to bake and cure the water out to adhere properly to the asphalt. This can be hindered by tree shade, tree droppings, rainfall, cloudy days, etc. To clarify, these circumstances do not always prevent proper adhesion, but do increase the probability of encountering an issue during the dry time of your sealing job vs a situation that does not . As a result of having any of these around the time of your driveway sealcoating, you have a much higher probability of encountering issues vs someone who does not.

Other Elements

Aside from shade there are many other elements that we are in constant battle against. Here is a list of things that we have to keep an eye out and warn our customers about:

Potholes – The large amounts of dirt and debris in the potholes fight against the bonding of sealer to asphalt.

Standing Water – Areas with drainage issues will prevent the sealer from sticking properly.

Low Temperatures under 45 Degrees – Temperatures need to average above 45 degrees in order for the sealer to have a chance at curing properly. Lower temperatures cause sealant to take longer for the water molecules to evaporate out of the sealer properly.

Natural Springs – Goes along with drainage issues. Natural springs have constant water pumping through that prevents sealer from sticking. They may also be hard to spot or find initially. Many times you may not know there is one until you notice the sealer problem.


Let’s dive into a few specific cases where customers and Hallman Asphalt have discovered issues and how we resolved them.

Documented Cases:

Study Number 1

Incident Description: Customer had areas of their driveway wash/fade away

Customer’s Location: Cottage Grove

Driveway Sqft: 6100 sqft

Completion Date: 7/19/2019

Outcome: Sealant has faded in areas under maple tree and next to large evergreens.

Causes: We believe that the faded sealant had a hard time curing properly before rain the next day. Although we had one of the hottest days of the year, the sealant that was in the shade wasn’t able to cure and evaporate the water out before the next rain had come. Similar to rain, high humidity doesn’t help the product cure any faster either.

Solution: Hallman Asphalt & the customer agreed to try one more time while watching the weather.


Study Number 2

Incident Description: Customer had areas of their driveway wash/fade away

Customer’s Location: Waunakee

Driveway Sqft: 1600 sqft

Completion Date: 9/5/2019

Outcome: Sealant has faded in areas under trees.

Causes: Due to the large amount of shade on this customers driveway, the sealant wasn’t able to evaporate its water molecules. Although this customer was warned, they still wanted to go forth with the project. This is the large risk involved with sealcoating in the shade.

Solution: Hallman Asphalt & the customer agreed sealing would continue with the patterns of wearing away, but decided to still focus on crack filling for future maintenance.


What Can You Do?

If you find yourself a homeowner who is dealing with some of these elements we have a few suggestions for you.

  • Pressure washing the asphalt prior to sealing can help get rid of tree droppings and sap. Make sure to allow time for drying prior to sealing.
  • Clients with trees/shade may want to do their maintenance more often like every year to every other year.
  • It is still crucial to have your cracks professional filled even if sealing doesn’t work great for your driveway. This can be done on its own & will ensure water is staying above the asphalt, protecting your base underneath.
  • Address the drainage issues by your driveway by potentially turning downspouts. Identify large drainage issues that may need patching or more permanent fixes. Depending on the issue, we can help with these problems. More about patching HERE.

The Product

This doesn’t mean all sealants are bad. The most commonly known sealant villain in the asphalt world is coal tar sealant, which typically contain 5-20% PAH’s. Coal tar is known for its high durability, but that comes at the price of being more toxic & less environmentally friendly.

Hallman Asphalt is proud to say we have never used a coal tar related product. The sealant we used up until this year was a petroleum based sealer that contained less than .7% PAH’s. We are staying up to date and complaint with Dane County sealant regulations.

Within Dane County rules & regulations have been put in place to change asphalt sealer & its contents to be safer. These rules & regulations ban the use of sealants above .1% PAH’s. While this is currently already in effect for this year in Dane County, it will be statewide at the beginning of 2021. Due to this ban, most sealers offered are water based emulsion sealers. For the most up to date ban click HERE.

Although this product is safer for the humans around it and the environment, it has some downfalls. They have yet to come out with a product that performs as efficiently as the older product did.

A few key points to remember about water based sealer:

  • Sealer contains 20-30% water, which is better for the environment.
  • No PAH threat to the environment (PAH: Polycyclic Aromatic Hydrocarbons, which is Carcinogenic)
  • Water based sealer contains minimal amounts of carcinogens compared to oil based sealer.
  • All sealcoat is applied at an outdoor temperature. Most believe it comes out hot, this is false.
  • Crack filler is laid down at 360-400 degrees.
  • Direct sunlight is required to bake/cure properly. If there isn’t direct sunlight, the water will not evaporate out of the product.
  • Trees usually win.

For now, they have not came out with a new rendition of this product to combat the flaws that is has, when it comes to dealing with the elements. We will continue to search for a product that will give our customers the best final outcome in most situations. This is a never ending battle that we will continue to fight.

In this battle of sealer vs. shade, it seems the trees have won…..for now.