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
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In the Northeast, well over half of sealcoat jobs fail early — sometimes in 30 days or less — because of outdated application methods, improper mixing, and weather conditions that simply don’t cooperate.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).
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.
✔ 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
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
✔ 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
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
✔ 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.
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.
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.
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.
✔ 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.
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.
✔ 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
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.
✔ 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.
✔ 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
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
✔ Require a multi-coat specification.
✔ Ask for proof of a 2-coat application
✔ Make sure the contractor allows proper drying time between coats
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
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
✔ Specify: “1st coat squeegee, 2nd coat spray.”
✔ Avoid small “residential-style” rigs on commercial jobs
✔ Demand commercial-grade equipment
When coal tar is banned and contractors water down AE sealer, it loses durability and can wear off within weeks.
Late May through early September offers the best dry-time conditions.
No — those require repair first or the sealcoat will fail immediately.
Usually from watering down the mix or failing to let the sealer cure fully.
Two coats minimum — one-coat applications are rarely durable in NJ/PA/DE/MD/NY climates.
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.