The customer asks for sealcoating. What they want is a lot that looks new and lasts. On most lots that takes both: crack sealing to keep water out of the base, and sealcoat to protect the surface. Explaining the difference up front is what saves the callback next spring that says the sealcoat didn't hold.
What crack sealing does
Water is what kills a lot. It runs down through open cracks into the base, softens it, freezes and expands, and pumps fines out under traffic. The base fails, and cracks turn into potholes.
Hot-applied rubberized crack sealant bonds to the walls of the crack, stays flexible through hot and cold, and keeps water and dirt out.
Some terms your customer may hear:
- Crack sealing is for working cracks, the ones that open and close with temperature. They're often routed first so the sealant has a clean reservoir.
- Crack filling is for cracks that don't move much, often with a less flexible material and no routing.
What size. Hot-pour sealant works best on cracks from roughly a quarter inch to about three-quarters of an inch wide. Hairline cracks don't take much material. Wider cracks usually need a mastic or a patch.
When crack sealing isn't the answer. Alligator cracking, the interconnected pattern that looks like chicken wire, means the base has already failed. Sealing or sealcoating over it just covers it up. That area needs to be cut out and patched, or milled and repaved. Mark it on the proposal and say why.
What sealcoat does
Sun and air oxidize the asphalt binder at the surface. The lot turns gray, gets brittle and starts to ravel as stone comes loose. Gas and oil drips soften it too.
Sealcoat puts a thin protective coat over the surface that slows that down, resists gas and oil, and makes the lot black again.
What sealcoat doesn't do:
- It doesn't add strength. It's a coating, not pavement.
- It doesn't seal cracks. Over an open crack, it bridges for a little while and then splits.
Coal tar or asphalt emulsion. Several states, including Washington and Minnesota, and a growing list of cities and counties, ban or restrict coal-tar sealers. Check before you price a product.
The order on the job
- Clean the cracks and the lot. Blow out the cracks, and treat oil spots so the sealer sticks.
- Crack seal and let it set, following the manufacturer's time before you coat over it.
- Patch any failed areas.
- Sealcoat, usually two coats, at the rate the manufacturer calls for.
- Let it cure before traffic. Weather and product decide how long.
- Restripe.
How to put it on the proposal
Show each piece as its own line: crack sealing (linear feet or a lump sum), patching (each area, by square foot), sealcoat (square feet, number of coats) and striping. The customer sees what each one does and what it costs, and can't compare your sealcoat-only number with someone else's "complete" number without noticing.
Add a line that says sealcoat is protection, not repair, and that crack sealing is what keeps water out of the base. When a customer drops the crack sealing to save money, have them initial it.
Related articles
- How to price sealcoating per square foot
- Asphalt vs. concrete driveways: walking a homeowner through the cost
- Pricing pothole repair: per hole or per square foot
Pavr is estimating and job software for paving, sealcoating, striping and concrete contractors. Crack sealing, crack filling, surface prep and sealcoat come built in, ready for your prices. Try it free →