What is a Type 1 slurry seal?

Type 1 is the finest ISSA A105 slurry seal gradation. It blends a fine aggregate passing a #4 sieve (with 100% typically passing #8) with asphalt emulsion, mineral filler, water, and additives, then spreads over existing pavement in a thin surface course roughly 1/8 inch thick.

Where is Type 1 typically used?

Type 1 is specified for low-speed, low-volume surfaces where a smooth, tight finish matters more than heavy wear resistance, residential streets, HOA roads, parking lots, bike paths, walkways, tennis courts, and airport shoulders and aprons.

How is Type 1 different from Type 2 and Type 3?

The three ISSA gradations differ in aggregate size. Type 1 uses the finest aggregate for maximum crack sealing and a smooth finish, Type 2 uses a general-purpose aggregate for residential and commercial streets, and Type 3 uses the coarsest aggregate for higher-traffic collectors and arterials that need extra skid resistance.

How long before traffic can return?

Most Type 1 applications open to traffic within 1 to 3 hours depending on ambient temperature, humidity, and emulsion type. Cooler or humid conditions extend cure time, and pedestrian access typically returns even sooner.

How long does a Type 1 slurry seal last?

Properly designed and applied, a Type 1 slurry seal typically performs for 5 to 7 years before another surface treatment is needed, depending on traffic loading, pavement condition at the time of application, and climate exposure.

Will slurry seal fix potholes or structural cracks?

No. Slurry seal is a preventive surface treatment, not a structural repair. Potholes, alligator cracking, and cracks wider than about 1/4 inch should be patched or crack-sealed before the slurry is applied.

What does the finished surface look like?

Type 1 cures to a uniform, matte black finish with a fine, tight texture. It restores the appearance of oxidized asphalt, sharpens the contrast for new striping, and improves skid resistance without the coarse feel of a chip seal.

When is the best time of year to apply Type 1 in Arizona?

Slurry seal is best placed when pavement and ambient temperatures are at least 50°F and rising, with no rain forecast for 24 hours. In Arizona, that gives a long placement window from early spring through late fall.

Slurry Products

Type 1 Slurry Seal

ISSA-spec fine-aggregate slurry seal built for residential streets, bike paths, parking lots, and low-speed surfaces where a smooth, uniform finish protects the pavement below.

602-256-7376

The product

A Tight, Fine-Graded Surface Seal

Type 1 is the finest of the three ISSA slurry seal gradations. Polymer-modified emulsion, fine aggregate, mineral filler, and water are mixed and spread in a thin surface course that fills hairline cracks, restores the wearing course, and locks moisture out of the pavement structure.

Meets ISSA A105 Type 1 gradation
Available with polymer-modified emulsion
Fast return to traffic (1 – 3 hours)
Restores skid resistance and surface color

Aggregate

Fine (passing #8)

Yield / SY

8 – 12 lbs

Cure Time

1 – 3 hours

Emulsion

CSS-1h / QS-1h

Why Type 1

THE PROVEN CHOICE FOR CITY STREETS

Every year an asphalt surface is left exposed to UV, water intrusion, and traffic, it loses flexibility and strength. A well-timed Type 1 slurry seal costs a fraction of a mill-and-overlay and can add 5 – 7 years of service life to pavement that is still structurally sound.

Seals out water

Fills hairline cracks and voids so water can't reach the base course, the leading cause of pavement failure.

Blocks UV oxidation

Restores a fresh black binder-rich surface that resists the raveling and brittleness caused by Arizona sun.

Improves skid resistance

Fine aggregate re-establishes a uniform macrotexture on polished or worn pavement.

Fast return to service

Traffic returns in as little as an hour, minimizing disruption for HOAs, businesses, and property owners.

Low-cost preservation

Typically 15 – 25% of the cost of a mill-and-overlay when applied at the right point in the pavement life cycle.

Curb appeal

Uniform matte-black finish sharpens striping contrast and lifts the appearance of the entire property.

Where it's used

BUILT FOR HIGH-USE STREETS

Type 1 is the go-to specification for low-speed surfaces that need a smooth, uniform finish and long-term protection from water intrusion and UV oxidation.

01

Residential Streets

Fine texture ideal for HOA roads, subdivision streets, and low-speed neighborhood surfaces where a smooth ride matters.

02

Bike Paths & Walkways

Tight aggregate profile delivers a comfortable surface for pedestrians, cyclists, and non-motorized traffic.

03

Parking Lots

Cost-effective seal for parking areas that need surface renewal without heavy build-up or coarse texture.

04

Airport Aprons

Approved for select apron and taxiway sealing where a fine-graded slurry meets specification requirements.

05

Filling Hairline Cracks

Slurry fills fine surface cracks and minor imperfections in one pass, sealing out water and oxidation.

06

Aesthetic Uniformity

Restores a clean, uniform black finish across weathered asphalt, ideal for high-visibility private drives.

How it works

The Type 1 Application Process

A Type 1 slurry seal is a job-mixed cold-applied surface treatment. The emulsion, aggregate, mineral filler, water, and additives are proportioned inside a continuous-run slurry machine and spread across the pavement in a single controlled pass. The result is a thin, uniform wearing course that bonds tightly to the existing asphalt below.

A short field video showing slurry placement in action, the continuous-run paver mixes and spreads the slurry in a single controlled pass.

01
Step
Surface preparation
Sweep and clean the pavement, patch potholes, and rout-and-seal any cracks wider than 1/4 inch before placement.
02
Step
Job-mix design
ISSA A143 mix design confirms aggregate gradation, emulsion residue, set time, wet-track abrasion, and cohesion values.
03
Step
Continuous-run placement
A calibrated slurry paver mixes and spreads the material behind the machine in a single 1/8-inch course.
04
Step
Cure and open to traffic
Water evaporates, the emulsion breaks, and the surface opens to traffic in roughly 1 – 3 hours depending on conditions.

ISSA A105 Type 1 Slurry SealExtends Pavement Life 5 – 7 YearsReturn to Traffic in 1 – 3 HoursSeals Water · Blocks UV · Restores SkidServing Arizona for 30+ YearsROC 155730 · ROC 109709 · ROC 105759

Spec at a glance

ISSA A105 Type 1

Aggregate gradation100% passing #4, ≥90% passing #8
Application rate8 – 12 lbs/SY of dry aggregate
Course thickness≈ 1/8 inch (3 mm)
Emulsion typeCSS-1h, QS-1h, or polymer-modified CQS-1hP
Residual asphalt10 – 16% by dry aggregate weight
Mineral filler0.5 – 2% Type I Portland cement or hydrated lime
Cure to traffic1 – 3 hours (weather dependent)
Expected life5 – 7 years

Is it the right fit?

Ideal Candidate Pavement

Type 1 works best on pavement that is still structurally sound but is starting to show early surface distress. Applied too late, after alligator cracking, rutting, or base failure, it will simply mirror the problems underneath.

Good candidate

Oxidized, gray, weathered asphalt with a rough dry surface
Fine surface cracks under 1/4 inch wide
Loss of fines / early raveling
Low- to medium-volume residential and commercial traffic

Not a fit, repair first

Potholes, alligator cracking, or base failure
Cracks wider than 1/4 inch (crack-seal first)
Standing water / drainage issues
Heavy truck routes and high-speed arterials (consider Type 2 or 3)

FAQ

Type 1 Questions, Answered

Straight answers from the estimators and crews who do the work across Arizona. Don't see your question? Call our office and talk to a real person.

Slurry seal being applied to an Arizona asphalt surface

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