About the Seal Coat Program

Streets in the above subdivisions will receive two different types of resurfacing products. The straight sections of road will receive what is called a "seal coat" and the cul-de-sacs will receive what is called a "fog seal".

A seal coat is a preventive maintenance surface treatment designed to preserve and extend the life of a street. It protects an aging pavement surface and seals up small cracks to keep water out of the pavement. The process starts by spraying a thin layer of liquid asphalt over the pavement. It is followed by the spreading of a thin layer of small rock. The surface is then rolled with a rubber tire roller and the street is reopened to traffic. Excess gravel is swept up by a vacuum street sweeper soon thereafter. It takes about a couple of months for the new surface to completely cure and lock the surface firmly into place with the road open to regular traffic.

Streets to be Resurfaced Next

After receiving notification of the work in advance by door hangers, flashing message signs or static message signs, please monitor the “Streets to be Resurfaced Next” schedule for an updated list of streets to be resurfaced the next two days.

Frequently Asked Questions

Why was the seal coat done?

Proper preventative maintenance, like seal coating, can help ensure that the existing pavement structure will last for many decades. Asphalt streets consist of a 1 1/2 to 2 inch layer of asphaltic concrete most people just call asphalt or pavement. Over time, the asphalt ages, weathers, and oxidizes. It becomes brittle and cracks. While the old surface appears smooth, it contains hairline cracks that, if not treated, would continue to widen, deepen and eventually form potholes.

How long does a seal coat take?

On most streets the work will only take about 30 minutes per block per lane. There might be a short period of time when the roadway in front of a residence is in an active work zone and, for safety reasons, the driveway is inaccessible. The first sweeping does not take place for 24 to 48 hours, so drivers should drive slowly. The surface is still “tender” for the remainder of the curing process. Tight turns, quick accelerations, or sudden stops and heavy braking may leave permanent marks in the surface in the first few months, especially on very hot days.

Why did you stop at the cul-de-sacs?

Tandem axle, double tire, garbage trucks make sharp turns in cul-de-sac bubbles and cut into a fresh seal coat thereby peeling up large sections of the surface. This is especially true in hotter weather. We will come back later with a different process to treat those areas. This other process is called a fog seal. Fog seals work better with the heavy, slow-speed turns at the end of the street.

The street was swept, but why is there still a lot of gravel scattered around?

We do not tow vehicles for the seal coat operation. If residents are unable to assist us by moving vehicles off the street, the sweepers will be unable to vacuum the rock from under them. Loose gravel also tends to accumulate at low spots, on the outside of curves and at intersections; however, all of this typically amounts to less than a gallon of gravel per block, and we would be glad to clean up remaining rock. If concerned residents will contact the resurfacing hotline, we will come back to sweep up any excess rock (512-943-3393) within 24 – 48 hours.

What about the areas skipped where cars were parked?

We ask that each resident help maintain the quality of their street by moving vehicles parked on the street in advance of the seal coat work. In the cases where residents have not moved their vehicles, seal coat production will be reduced and we will be back with a hand crew to cover those spaces at a later date. This will be more expensive and result in fewer streets that can be seal coated that year.

The seal coat surface is too rough. My kids can’t roller blade and my dog can’t walk in the street. What can be done to smooth it out?

The surface will smooth out with traffic over the first four to six weeks as the material cures and the gravel particles interlock and embed into a tighter surface. While this process is slow, it is happening. The street will look completely different in eight to twelve weeks with a darker, tighter, smoother surface. It will never be as smooth as the old surface; however, it will provide good wet weather traction, preserve the remaining life of the street, and seal most of the cracks.

When can I walk on the asphalt again?

It is best to wait at least 30 minutes after rock has been down before walking on the new pavement surface. Remember that the curing process takes longer than 30 minutes so, if you choose to walk outside, be sure to remove shoes before going back in your house and make sure that all pets’ feet are clean before going back in, as well.

How often do you need to do seal coat maintenance?

Seal Coat Maintenance is often performed on an 8 – 10 year basis. If preventive maintenance, crack sealing and seal coat resurfacing, e.g., is conducted on Williamson County roads and streets on a routine basis, the existing pavement structure will last for many decades.

Two different seal coats of varying ages: on the left is a seal coat approximately a couple of months old, while the one on the right is approximately four years old.

Why not pave the street with material like the one we already have? What is the difference in cost?

What the residents are used to driving on is a pavement structure that has a hot mix asphalt pavement (HMAC) surface with a flexible crushed rock base below it. The cost to resurface an existing road using a standard HMACP overlay is 5 to 6 times more expensive than resurfacing a road with a seal coat. Should the roads not be resurfaced at all, they will continue to degrade and there comes a point when resurfacing maintenance is no longer effective and the road would need to be rebuilt. The cost to rebuild a road is 10 - 15 times greater than the cost of seal coating.

Where else have they used the seal coat process?

The City of Austin resurfaces all residential streets and most boulevards using a seal coat. To see recent seal coat applications, you may wish to drive through Shenandoah, Block House Creek or Brushy Creek North subdivisions.

My street was just resurfaced. Is this the final product?

Yes and No. Yes, this is the product that is being utilized to resurface all subdivision roads in the unincorporated areas of Williamson County. As expressed earlier in the FAQs, it is much more cost effective to resurface with a seal coat than with HMAC, due the County's budget constraints. No, what you see on your street the day of resurfacing is not how it will look in the future. We spread more rock than is necessary to decrease the likelihood that residents would get asphalt on their vehicles and feet. That excess rock will be vacuumed up (it might take a couple of trips down your street) and the remaining rock (that which adhered to the asphalt) will continue to work itself into a tighter structure with continued driving upon it. The rock will also tend to darken over time.

Where do I go for more information?

You may call our Resurfacing Hotline, 512-943-3393, to hear daily updates of roads on which our crews are currently working or you may visit our county website at www.wilco.org/roads

Get Informed

There are some important steps in a successful resurfacing application that occur months before the product is actually applied. County Road and Bridge crews will start preparing your streets in the Fall and Winter for resurfacing operations that will occur the following Spring and Summer. To learn more, click here.

There are some important steps in a successful resurfacing application that occur months before the product is actually applied.  County Road and Bridge crews will start preparing your streets in the Fall and Winter for resurfacing operations that will occur the following Spring and Summer.

In preparation for the resurfacing, County crews will:

a) Assess the street and determine if there are any locations where the road base (foundation) has been overly stressed and failed.  If this is the case, we remove the failed material, replace with a road base material and patch the surface. 

b) We then broom the streets to remove loose debris.  When the debris is removed, we can better analyze the condition of the road and also begin to crack seal. 

c) Larger cracks need to be filled prior to resurfacing.  Road and Bridge uses a hot applied rubber product to fill the cracks and seal them off.  While some residents might consider the resulting crack sealant to be unattractive, it is very successful at preserving the integrity of the street.  Crack sealant is often applied during colder months when the crack is wider due to thermal contraction. 

d) During the above processes, a Road and Bridge crew will visit the street and spray herbicide on the shoulders of the road.  Root systems from grasses and weeds assist in the crack proliferation of the roadway surface and should be removed prior to resurfacing.   The Road and Bridge crew will also trim and remove tree limbs that will impede the large construction equipment during resurfacing operations. 

e) Next, a cold applied paving material will be spread on the roadway to level uneven spots and repair the shoulder.  This process requires larger equipment such as motor graders, haul trucks and rollers to maneuver and perform a finish type work on narrow streets and roads. 

Once all of these preparatory steps have been performed, the binders in the different products need time to cure. You might not see any maintenance activity again until we are ready to resurface the roadway.  We appreciate your patience and understanding during this inconvenient, but much needed, process.