What a Scratch Course Is on an Asphalt Job

A scratch course is a thin, variable pass that works mix into low texture and small ruts before the main surface. It is thinner than a full leveling of deep ruts. The rectangle formula misses those tons if you only measured the final surface thickness.

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A thin pass into the texture

Crews call it a scratch course when they drag a thin, variable pass of hot mix into the low texture and the small ruts before the main surface goes down. The paver or the lute scratches mix into the voids so the next lift is not bridging over a rough, hungry surface. It is thinner than a full leveling course meant for deep ruts. If you only hear overlay, you may miss this pass entirely. Ask whether the quote's tons include the scratch or only the final surface thickness. Ask them to say scratch in the quote. A job with a scratched texture uses more mix than a smooth mat of the same final inches.

Where the rectangle formula goes quiet

The planning formula, area times inches times 145 divided by 24,000, assumes one compacted thickness. A scratch course adds a variable skim the final surface measurement does not fully describe. Suppose the surface is 1.5 inches on 2,000 square feet. That is 2,000 times 1.5 times 145 divided by 24,000, about 18.1 tons, as a planning estimate for the surface alone. A scratch that averages a quarter inch over the same area is 2,000 times 0.25 times 145 divided by 24,000, about 3.0 tons more. The plant ticket is the real weight of each load. If the quote states one tonnage, ask whether those 3 tons, or whatever the texture needs, are inside it or extra.

Scratch mix is not a repair for a broken section

Small ruts and open texture are what a scratch is for. A deep wheel path, a pumping spot, or a pothole needs leveling or a patch, not a skim that disappears into the hole. Ask the crew to say which lows get a scratch and which get a real repair. The scratch is still hot mix, so density planning stays near 145 pounds per cubic foot unless the plant says otherwise, and the ticket remains the real weight. If the scratch cools before the surface arrives, the bond between them is tack, a line you should see on a cooled-lift quote, not a spray job for the homeowner. Look at the finished mat. A scratch that was too thin to fill the texture shows up as a hungry, open surface under the new cap.

A practical sequence

Ask whether a scratch pass is included before the main surface.
Ask if the quoted tons include that variable skim or only the final thickness.
Plan any average scratch depth at 145 pounds per cubic foot as an estimate.
Use a patch or a leveling course for deep ruts and holes, not a skim.

The mistake to skip

Measuring only the final surface thickness and leaving the scratch tons out of the order.

Questions people ask

How is a scratch course different from leveling?

A scratch course is a thin variable pass into low texture and small ruts. Leveling is the heavier variable fill for deeper ruts, birdbaths, and bad joints. Both add tons a single rectangle can miss. Ask which one the quote includes. The plant ticket is the real weight. Deep failures need a patch or a base repair, not a skim.

How do I estimate scratch tons?

Pick an average extra depth, then use area times that depth in inches times 145 divided by 24,000. A quarter inch on 2,000 square feet is about 3.0 tons as a planning estimate, on top of the surface course. The plant ticket is the real weight. Ask the crew if their tonnage already includes that scratch.

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