# Preparing the ground before asphalt paving Published: 2026-09-16 **In short:** Asphalt does not last if the layer beneath it is weak. Proper preparation means stripping the topsoil, a foundation of ballast and crushed stone compacted in layers, a fall that sheds water off the surface, and priming with bitumen emulsion before the asphalt is laid. --- When an asphalted yard cracks and sinks after one winter, it is almost never because of the asphalt. It is because of what was done — or not done — underneath it. ## Why asphalt fails An asphalt surface is a few centimetres thick. It is not a load-bearing structure: it is a wearing layer that spreads the load to the foundation underneath. If the foundation moves, the asphalt cracks. If water gets underneath and freezes, the asphalt lifts and breaks. So the job is decided by what is underneath, not by what you can see. ## Step 1: Topsoil stripping The topsoil is removed — soil with roots and organic matter. It rots over time and leaves voids, however well you compact on top. The stripping depth depends on the ground. You dig until you reach clean, load-bearing soil. ## Step 2: Checking the ground underneath If under the topsoil you find soft clay or old fill, the foundation is not laid directly on top of it. You dig deeper and replace it, or you stabilise it. The clear sign: if the ground “pumps” under the machine — that is, it visibly moves as the machine passes — it is not ready to take anything. ## Step 3: The foundation Ballast is laid, then crushed stone on top. The ballast provides the bulk, and the crushed stone provides the stability, because its edges lock together. **In layers, compacted separately.** This is where mistakes are made most often. A thick layer compacted just once stays loose underneath and settles in the first year. ## Step 4: The fall Water needs somewhere to go. A perfectly flat surface collects water in puddles, and standing water gets in through the joints and destroys the structure underneath. A slight fall is given towards a drainage channel, the street or a green area. It is set before the final compaction, not afterwards. ## Step 5: Priming Before the mix is laid, the surface is sprayed with bitumen emulsion, using the bitumen sprayer. Its role is to bond the asphalt surface to the layer underneath. Without priming, the asphalt sits on the foundation instead of sticking to it, and it can come away in slabs. ## Step 6: Laying and compaction The mix is laid with the paver, at temperature, and compacted immediately with tandem rollers, while it is still hot. Compaction done too late has no effect. ## How to spot an incomplete quote If the quote only talks about square metres of asphalt and does not mention topsoil stripping, the foundation, compaction and the fall, ask for clarification. The price difference between a complete quote and one that skips the preparation is exactly the difference between a job that lasts and one that has to be redone two years later. --- ## Contact Phone: +40 729 553 449 Contact form: https://inchiriez-utilaje.ro/en/contact/ Article: https://inchiriez-utilaje.ro/en/blog/ground-preparation-before-asphalt-paving/ Romanian version: https://inchiriez-utilaje.ro/blog/pregatirea-terenului-inainte-de-asfaltare/