The Top Problems With Asphalt Sealcoating in New Jersey, Pennsylvania, Delaware, Maryland & New York — And How to Avoid Them (2026 Guide)

By FixAsphalt.com — Commercial Pavement Advisors for the Northeast & Mid-Atlantic

If you manage or own a commercial property anywhere in New Jersey, Pennsylvania, Delaware, Maryland, or New York, you already know that asphalt sealcoating is one of the most important maintenance steps for extending the life of your parking lot.

Done correctly, sealcoating:

• Blocks UV oxidation

• Protects against water penetration

• Shields against winter freeze–thaw cycles

• Improves curb appeal

• Extends pavement life by 3–5 years per application

Premature failure of a 1-year-old pavement sealcoating application in New Jersey

But here’s the truth most contractors won’t tell you:
In the Northeast, well over half of sealcoat jobs fail early — sometimes in 30 days or less — because of outdated application methods, improper mixing, and weather conditions that simply don’t cooperate.

This blog breaks down the real problems with asphalt sealcoating in our region, why they happen, and exactly how to avoid them using the Marcus Sheridan “They Ask, You Answer” framework (your customers’ questions, answered honestly and directly).

1. Sealcoating in the Wrong Weather Conditions (Most Common Cause of Failure)

The Problem

Sealcoating requires:

• Pavement temps above 55°F and rising

• Dry conditions

• Low humidity

• Enough sunlight to drive evaporation

• No rain for 24 hours

In the Northeast and Mid-Atlantic, the biggest enemies of sealcoat curing are:

• Cool spring mornings

• Heavy nighttime moisture / dew

• Early fall temperature drops

• Unexpected rain showers

• High humidity after thunderstorms

When a contractor seals too early or too late in the season “to squeeze in jobs,” the result is predictable:

❌ Streaking
❌ Early wear-off
❌ Tracking
❌ Gray patches
❌ Flaking and peeling

If the sealer doesn’t completely cure — not just “dry” — it will fail.

How to Avoid It

✔ Only sealcoat when pavement temps are 55°F+ for 6–8 hours
✔ Avoid late afternoon applications
✔ Avoid fall work unless the 5-day forecast is clear
✔ Never sealcoat when nighttime temps drop below 50°F

Is it too cold to sealcoat my asphalt parking lot? Learn More

2. Improper Surface Preparation (A Major Issue With Inexperienced Contractors & Poorly Trained Application Crews)

The Problem

Sealcoat cannot bond to:

• Dirt

• Debris

• Sand

• Loose aggregate

• Pollen (major issue in PA, NJ & DE)

• Oil drippings

• Moisture trapped in pores

The Northeast accumulates heavy pollen and dirt during spring, which many contractors simply blow around with leaf blowers instead of mechanically cleaning.

If you sealcoat over contamination, you get:
❌ Peeling
❌ Bald spots
❌ Dust “pulling up” under tires
❌ Patchy appearance

How to Avoid It

✔ Require mechanical scrubbing or steel-broom prep
✔ Insist on oil-spot primer where needed
✔ Demand that edges, corners, and curb lines are cleaned — not just the open areas
✔ Avoid spring sealcoating until tree pollen season passes

3. Applying Sealer Over Alligator Cracking or Structural Failures

The Problem

Sealcoating is not a repair method for:

• Alligator cracking

• Base failures

• Potholes

• Depressions

• Soft spots

• Edge breakup

Many low-cost contractors will sealcoat over damaged areas to “hide” them temporarily.

Those areas will:
❌ Reflect through immediately
❌ Bubble or peel
❌ Continue to deteriorate
❌ Cause bigger failures next season

How to Avoid It

✔ Alligator cracking needs mastic repair or patching, not sealcoat
✔ Potholes must be cut-out and replaced or infrared repaired
✔ Depressions need leveling or milling before sealing
✔ Cracks over ¼” require hot rubber crack sealing

Sealcoat is protection, not repair.

4. Coal-Tar Ban in New York & Maryland — Why This Changes Everything

The Problem

For decades, old-school contractors all over NY, NJ, and PA used coal tar sealer, which:

• Was extremely durable

• Could withstand being watered down

• Created a hard, chemical-resistant coating

Some contractors even mixed in 50% water and still got a year of protection because coal tar was forgiving.

But now:

• New York and Maryland have banned coal tar, along with Massachusetts and Maine.

• Other Mid-Atlantic states are considering similar bans

• Contractors must now use asphalt emulsion (AE) or steam-cracked asphalt sealers

Asphalt emulsion is NOT coal tar.  
It cannot be watered down.
It cannot be misapplied.
It requires strict manufacturer specifications to function.

Why This Causes Failures

Many old-timers are still using the same “coal tar mindset” with AE sealer:

• Adding 50–100% water

• Skipping sand load and polymer additives

• Not mixing properly

• Using the wrong application rate

• Sealing in poor weather

• Applying too thin

With asphalt emulsion, this results in disaster:
🚨 It can wear off in 30 days.
🚨 It can fail before the next rainstorm.
🚨 It can look gray, patchy, and uneven immediately.

AE requires discipline coal tar never needed.

How to Avoid It

✔ Ask for manufacturer specs in writing
✔ Call the manufacturer to perform a background check on the contractor
✔ Demand full sand load
✔ Require 2 coats on commercial properties with proof of application
✔ Do NOT accept “we’ve always done it this way” as an answer
✔ Never allow 50% water — ever

In NY and MD, proper application is the only path to durability now.

5. Using the Wrong Mix or Too Much Water (Most Common Cause of 30-Day Failures)

The Problem

With asphalt emulsion sealers (now required in NY & MD), the following causes immediate failure:

❌ Adding too much water
❌ Not adding the required amount of sand
❌ Not using additive
❌ Using poor-quality water
❌ Not mixing thoroughly
❌ Not keeping material agitated

AE is extremely sensitive to dilution.
Most manufacturers recommend:

20–25% water max
3–5 lbs of sand per gallon
Additive for faster cure and durability

If a contractor is still stuck in the old “coal tar + water” mentality… your sealcoat will not last.

How to Avoid It

✔ Require the contractor to show the mix ticket
✔ Ask what their standard water-cut percentage is
✔ Avoid any contractor who says:

“We cut it based on how it flows.”
This is code for watering it down to save money.

✔ Ask if they use:

• Sand load

• Polymer additives

• Proper agitation

• Specification sheets

6. Sealcoating at the Wrong Time of Year (Northeast Edition)

The Problem

Sealcoating has a short season in the Mid-Atlantic due to:

• Freeze–thaw cycles

• High nighttime moisture

• Short daylight windows

• Early fall temperature drops

Bad timing = bad results.

Real-World Timing Guidelines (Based on 20+ Years Field Observation):

✔ NJ/PA/DE/MD/NY
Best: May 25 – September 15
Good: April 15 – May 25
Fair/Marginal: September 15 – October 10
Poor: October 10 – April 15

Once daily highs consistently drop below 60°F, failure risk skyrockets.

How to Avoid It

✔ Plan your sealcoat the same way you plan HVAC maintenance
✔ Avoid fall unless absolutely necessary
✔ Never let a contractor sealcoat with rain “in the forecast but maybe it will hold off”

Is it too cold to sealcoat my asphalt parking lot? Learn More

7. One-Coat Jobs on Commercial Properties (A False Economy)

The Problem

A single coat of AE or blended sealer on a high-traffic commercial property won’t last.

You need:
✔ 2 coats minimum
✔ Sometimes 3 on entrances, drive lanes, and truck routes

How to Avoid It

✔ Require a multi-coat specification. 
✔ Ask for proof of a 2-coat application
✔ Make sure the contractor allows proper drying time between coats

How to Guarantee Your Contractor Actually Applied Two Coats of Pavement Sealer

The only way to guarantee your contractor applied two full coats of pavement sealer is to require visible, documented verification before and during the job. A legitimate contractor will gladly show you the difference between the first coat and second coat while work is in progress: the first coat appears darker, matte, and absorbed into the asphalt, while the second coat creates a uniform black finish that sits on top. Ask for time-stamped photos or videos showing the first coat fully dry before the second coat is applied, along with mix tickets, material quantities delivered, and square-foot coverage rates that match the manufacturer's specifications. You should also require the contractor to mark off sections of the lot so you can inspect the first coat in person before they proceed with the second. Any contractor who hesitates, rushes, or refuses to provide this level of transparency is almost certainly planning to apply only one thin spray coat instead of the full two-coat commercial application you’re paying for.

Read our guide on how to make sure a sealcoating contractor is telling you the truth:   Download The FREE Guide

8. Poor Application Methods (Spray vs. Squeegee vs. Hybrid)

The Problem

Commercial properties require consistent, professional application methods:

• 1st Coat Squeegee / 2nd Coat Spray is the longest-lasting application in the industry

• Only professional pavement sealcoating equipment can apply pavement sealer to meet the manufacturer's specifications and achieve longevity.  Fly-by-night contractors using buckets, drums, square plastic totes, or other "cracker-jack" equipment are not capable of performing the job correctly.  Contractors without the proper preparation equipment (large walk-behind air blowers to prepare the surface), working out of the back of a pickup truck, and unskilled application crew will leave behind a sub-standard finished product.

• Entrances and high-traffic areas are best suited for a 3-coat application

• Pavement sealer requires a minimum of 24 hours of cure time before being opened to traffic

How to Avoid It

✔ Specify: “1st coat squeegee, 2nd coat spray.”
✔ Avoid small “residential-style” rigs on commercial jobs
✔ Demand commercial-grade equipment

Frequently Asked Questions (FAQ)

FAQ 1 — Why does sealcoat only last 30 days in some states like NY and MD?

When coal tar is banned and contractors water down AE sealer, it loses durability and can wear off within weeks.

FAQ 2 — What’s the best time of year to sealcoat in New Jersey or Pennsylvania?

Late May through early September offers the best dry-time conditions.

FAQ 3 — Can you sealcoat over cracks or potholes?

No — those require repair first or the sealcoat will fail immediately.

FAQ 4 — Why does sealcoat turn gray or streaky?

Usually from watering down the mix or failing to let the sealer cure fully.

FAQ 5 — How many coats do commercial properties need?

Two coats minimum — one-coat applications are rarely durable in NJ/PA/DE/MD/NY climates.

Conclusion: Sealcoating in the Northeast & Mid-Atlantic Requires Expertise, Not Shortcuts

Sealcoating is still one of the highest-ROI pavement maintenance activities — when it’s done correctly.

But with coal tar bans, changing weather patterns, and increasing liability concerns, commercial properties in NJ, PA, DE, MD, and NY need a contractor who understands:

✔ AE vs. coal tar chemistry
✔ Weather windows
✔ Proper mixing
✔ Multi-coat applications
✔ Surface prep
✔ Crack sealing + base repair requirements

When done right, sealcoating protects your parking lot for years.
When done wrong, it can fail in 30 days — and cost you far more in the long run.