What sealcoating involves
Sealcoating is the application of a liquid pavement sealer over an asphalt surface. Sealers are either coal tar based or asphalt based, and PCTC’s practices allow application by squeegee, brush or spray. It is not a structural repair. The Pavement Coatings Technology Council (PCTC) best management practices state that wide cracks, extensive alligator cracking and soft or sunken spots are repaired first, and patches cure before sealer goes down. See pothole repair and parking lot repair.
A commercial sealcoating job typically runs in this order:
- Repair. Failed areas are patched and allowed to cure.
- Crack filling. Cracks of about 1/4 to 3/4 inch are cleaned and filled with an approved crack sealant; hairline cracks are ignored. Colorado Asphalt Pavement Association (CAPA) guidance calls for cracks wider than 1 1/2 inches to be repaired with hot-applied mastic.
- Oil and grease spots. Surface spots are scrubbed and flushed; deeper spots get an oil spot primer, and badly saturated pavement is replaced to full depth.
- Priming where needed. Highly oxidized surfaces may be primed with an asphalt emulsion or acrylic primer, which cures for 24 hours before sealer.
- Cleaning and edging. The surface is cleaned immediately before application, edges are done first and storm drains are protected.
- Application. CAPA’s guidance calls for two coats in all areas and a third in high-traffic areas as needed, at 0.1 to 0.15 gallons of mix per square yard per coat, with each coat dry before the next.
- Cure and restriping. Barricades stay up until the sealer and new markings are dry and hard enough for traffic.
Requirements and standards for sealcoating
Weather limits. PCTC’s practices call for an ambient temperature of at least 50°F and rising and a pavement temperature of 60°F and rising, with no work in cold or wet conditions. Sealer is not applied when rain is imminent, at least two hours of daylight should remain after completion, and frozen emulsion is never used. CAPA’s guidance adds no freezing expected for 24 hours and no rain expected within 8 hours after completion. PCTC does not recommend sealcoating enclosed or permanently shaded areas.
New pavement. Both guides call for new hot-mix asphalt to cure for 30 to 90 days before sealing. PCTC calls for at least 90 days for cold mix.
Storm drains. PCTC’s practices call for every drain to be identified before work and kept free of sealer, with irrigation suspended until the lot reopens.
Coal tar restrictions. USGS reports that coal tar sealcoat contains about 1,000 times more polycyclic aromatic hydrocarbons (PAHs) than asphalt-based sealcoat, that coal tar is classified as a known human carcinogen, and that its use is prohibited in some states, counties and municipalities. Minnesota bars application of coal tar sealcoat on or after January 1, 2014 under Minn. Stat. § 116.202, including by out-of-state contractors. Austin, Texas banned coal tar sealants in 2006 and in 2019 expanded the rule to any sealant above 0.1 percent PAH by weight. Product type is confirmed against local rules before each job.
ADA restriping. Sealcoating covers existing markings, so the lot is restriped. The Department of Justice states that a business restriping a parking lot must provide accessible parking spaces as required by the 2010 ADA Standards, counted separately for each parking facility. At least one of every six accessible spaces must be van accessible. Car spaces are at least 96 inches wide with a 60-inch access aisle; van spaces are 132 inches wide with a 60-inch aisle or 96 inches wide with a 96-inch aisle. Signs are mounted with the bottom edge at least 60 inches above the ground. State and local codes can add requirements.
Preventive maintenance schedule for sealcoating
A planned sealcoat cycle finds cracks while they are small, before they become potholes that drive emergency calls and trip claims. It also keeps restriping and accessible parking on a documented schedule.
| Task | Recommended frequency | Basis |
|---|---|---|
| Reapply sealcoat | Every 2 to 3 years | Manufacturer recommendation, as reported by the City of Austin |
| Inspect surface for cracks, raveling, oil spots and worn markings | Twice a year, spring and fall | Facility First program default, adjusted per site |
| Check high-traffic drive lanes and entrances for wear | Annually | Facility First program default, adjusted per site (Austin notes wear in high-traffic areas within months) |
| Clean and fill cracks of about 1/4 to 3/4 inch | Before each sealcoat application | PCTC best management practices |
| Clean and prime oil and grease spots | Before each sealcoat application | PCTC best management practices |
| Allow new asphalt or patches to cure before sealing | 30 to 90 days | PCTC and CAPA guidance |
| Sweep the sealed surface | 1 to 2 weeks after application | PCTC best management practices |
| Restripe and verify accessible space count, dimensions and signs | At every restriping | DOJ, 2010 ADA Standards |
| Confirm product type and safety data sheet against local coal tar rules | Before each application | Minnesota Pollution Control Agency; City of Austin |
The authority having jurisdiction, the manufacturer and the property’s insurer can require more frequent service, and each location’s schedule is set in its program and recorded on every visit.
Signs a parking lot needs sealcoating
- Oxidized, weathered asphalt that has faded from black to gray
- Hairline and small cracks spreading across drive lanes
- Oil and fuel stains in parking stalls
- Faded striping and accessible parking markings
Alligator cracking, depressions and potholes point to repair first, not sealcoating alone.
Records to keep
- Product name, type and safety data sheet for each application
- Date, weather and temperature readings at application
- Number of coats and areas covered, with a site map
- Crack filling and patching completed beforehand
- Storm drain protection photos
- Striping layout, accessible space count and van-accessible spaces
- Before and after photos, and the next scheduled sealcoat date
How Facility First runs sealcoating across a portfolio
- Request. The location or facilities team submits photos and lot details, or the work comes from a scheduled condition review. See facility condition assessment.
- Triage and approval. Facility First confirms repairs needed first, local product rules, weather windows and a closure plan. Work within the client’s approval limits proceeds; larger lots are quoted for approval first.
- Dispatch. A vetted local paving provider with the required licenses and insurance receives the work order.
- Completion. The provider records conditions, product and coats, protects drains and restripes to the approved layout with photos.
- Verification and invoice. Facility First checks the work and striping against the request, files the records on the location’s history in PostControl and invoices in one format.
What affects the cost of sealcoating
- Lot area and layout, including islands and curbs
- Pavement condition and the repair and crack filling needed first
- Oil spot treatment and priming
- Product type and number of coats
- Restriping, stencils and accessible parking signage
- Phasing to keep part of the lot open
- Night or weekend work
- Local product restrictions and stormwater protection
Sealcoating for retail stores, restaurants and offices
Retail stores. Lots are phased so part of the parking stays open during trading hours, with entrances and accessible spaces maintained.
Restaurants. Drive-thru lanes and pickup bays carry traffic through most of the day, so work is often scheduled overnight or between dayparts, with curing time planned around opening.
Offices. Weekend application suits most office lots, with tenants notified of closures in advance.
Frequently asked questions
How often should a parking lot be sealcoated?
The City of Austin reports that sealcoat manufacturers recommend reapplication every 2 to 3 years, and that wear in high-traffic areas can show within a few months. Each location’s interval is set by its condition and traffic.
Does sealcoating fix cracks and potholes?
No. Sealcoating protects the surface. Wide cracks, alligator cracking and potholes are repaired first, and patches cure before sealer is applied.
How long does a lot stay closed after sealcoating?
CAPA’s guidance calls for at least 8 hours of drying in good conditions before traffic, and in marginal weather this can exceed 24 hours. Barricades stay up until the sealer and striping are dry.
What weather is needed for sealcoating?
PCTC’s practices call for air at 50°F and rising, pavement at 60°F and rising, and no rain imminent. Work is not done in cold or wet conditions.
Is coal tar sealer still allowed?
It depends on the location. Minnesota and Austin, Texas restrict it, and USGS reports bans in some other states, counties and municipalities.
Does the lot have to be restriped to ADA standards?
The Department of Justice states that restriping a parking lot requires providing accessible spaces under the 2010 ADA Standards, including van-accessible spaces.
Sources
- Pavement Coatings Technology Council: Best Management Practices for Sealcoating
- Colorado Asphalt Pavement Association: Best Practices for Seal Coats
- USGS: Coal-Tar-Based Pavement Sealcoat, PAHs and Environmental Health
- Minnesota Pollution Control Agency: Coal Tar-Based Sealcoat FAQs
- City of Austin: Pavement Sealant FAQ
- U.S. Department of Justice, ADA.gov: Restriping Parking Spaces