Asphalt Paving and Repair (FAQ)

Here are some frequently asked questions (FAQ) about asphalt paving and repair.

What is the difference between an overlay patch and a saw cut?

An overlay repair is when the asphalt is applied over the hole and the edges of the new asphalt are feathered out to make it a semi-smooth transition.  These are the most common and the least expensive.  This type of repair requires the use of "tack".

A saw cut repair is the process where the existing asphalt is cut out and removed and the area is then filled with new asphalt material.  These also require tack.

What is tack?

Tack is a liquid asphalt binder "glue" that bonds the new material to the old.  We use this on all of our projects.

What is milling?

Milling is a cold planing process where the existing asphalt is ground down to make a smooth transition where it is required.  For example, where the new asphalt meets the old pavement or existing concrete next to a curb, sidewalk, drain, etc.

What are the different types of asphalt?

There are several different types of asphalt mixes.  Asphalt mixes are regulated by the State.  This is to protect consumers and contractors from inadequate asphalt being used in construction projects.  All asphalt plants have a quality control person on-sight to monitor compliance with these regulations.  

The two most common asphalt mixes are:

  • Type S-1: This is the heavy commercial mix with one-inch aggregate in the mix.  The finish of this is very coarse and not acceptable for most applications.
  • Type S-3: This is the mix design that is most common in residential and lighter commercial applications.  This has a smooth finish for a better looking product.

What do I need to know about pavement thickness?

Pavement thickness is the key to a quality paving job.  Most new construction jobs in our area are specified at 1.5 inches.  The industry standard for overlay paving is 1 inch of paving thickness.  Not everyone understands that asphalt will compact down 20 to 25% so a quality job needs to lay down 20 to 25% more material than the target pavement thickness or you won't be happy with your final product.

All of the estimates that come from Key Sealcoating are based on the final, after-compaction, measurements.  1 inch means 1 inch after compaction.

What do I need to know about compaction?

Compaction is the second most important issue after proper pavement thickness.  The better the compaction, the harder the surface.  The harder the surface, the longer the wear live of your pavement.  The longer the wear life the greater the return on your investment, etc.

To achieve maximum compaction you need the proper equipment.  Key Sealcoating have invested large amounts in compaction equipment to achieve the highest standard in the paving industry.


I hope this background information will help you plan your next project.  If you want to know more, give me a call.


Pat McDowell, Owner, Key Seal Coating, Inc.
Phone: (941) 758-1517
Fax: (941) 758-6917
Email: pat @