In the paving industry, we often encounter a hesitancy to commit to full-depth reclamation (FDR) or complete replacement. Clients naturally gravitate toward the lower line item: the overlay. However, as professionals, we know that an overlay is only as good as the subgrade it sits on. Placing new Hot Mix Asphalt (HMA) over a compromised base is a violation of fundamental pavement mechanics. Black Diamond Paving approaches every estate project with a focus on load distribution and shear strength, ensuring that the chosen method—whether resurfacing or replacing—meets the structural demands of the property.
To understand the distinction, one must look at the cross-section. A standard resurfacing job typically involves milling the top 1.5 to 2 inches of the existing wearing course. This removes surface oxidation and minor transverse cracking. We then apply a tack coat—a bituminous emulsion—to bond the new asphalt to the old. This works beautifully if the base course (the aggregate layer) is stable. However, if there is evidence of "pumping"—where fine soil particles are forced up through the pavement by water pressure—an overlay will fail catastrophically. The new layer will delaminate or crack because the foundation is moving.
Replacement, or reconstruction, addresses the root cause: the subgrade. On many older estates in Chester Township, the original driveways were built with insufficient base depths for modern loads. Today’s delivery trucks and construction equipment exert point loads that exceed the design limits of 20-year-old driveways. When we replace, we excavate down to the native soil, proof-roll it to identify soft spots, and install a dense-graded aggregate base. We then lay a binder course (large stone mix) followed by a top course (fine stone mix). This composite structure distributes weight effectively, preventing the rutting that plagues older driveways.
Drainage engineering is the final differentiator. An overlay can adjust the cross-slope slightly to improve sheet flow, but it cannot correct a reverse grade. If water is flowing back toward the residence or pooling in the center due to subgrade settlement, replacement is the only engineering solution. It allows us to manipulate the elevations of the subgrade itself. When vetting Asphalt Paving Contractors in Chester Township NJ, property owners should expect a discussion about elevations and base stability, not just square footage prices.
In summary, the decision is dictated by the structural pathology of the pavement. If the base is sound, an overlay is a valid preservation strategy. If the base is yielding or the drainage is inverted, replacement is the only professional recommendation. Ignoring these engineering realities inevitably leads to premature failure.
For a technical assessment of your pavement structure, visit https://www.blackdiamondpaving.co/ to consult with our specialists.