What is the required depth for gravel and asphalt in a residential driveway?

Hi the right way is: the foundation should be dug 12 to 15 inches deep, then 3/4 inch crushed gravel poured in up to 2 inches below grade. Then a 3 inch layer of hot asphalt is applied, which is then rolled and compacted one full inch to bring it down to grade. Hope this helps.

You should be highly concerned because this installation fails to meet Ontario residential standards and will structurally fail within one to two winters. A gravel base must be a minimum of 15 cm to 20 cm thick to withstand Canadian frost heaves; your contractor’s 5 cm layer is completely inadequate to support a vehicle. While your total asphalt thickness of 7.5 cm is normally acceptable, laying it directly over thin gravel and soft, uncompacted dirt means it will quickly crack and sag. Have you already paid the contractor in full, and are you noticing any sinking where your car tires park?

A common residential installation generally includes: A well-compacted granular base of approximately 15–20 cm (6–8 inches), depending on the soil conditions and expected vehicle loads. A compacted asphalt surface totaling approximately 5–7.5 cm (2–3 inches), which may be installed in one or two lifts. If your driveway was installed directly on bare soil with less than 5 cm of gravel base, that is significantly below what is commonly used for a durable residential driveway. While your total asphalt thickness of roughly 7.5 cm (about 3 inches) is generally adequate, asphalt alone cannot compensate for an insufficient base. Without a properly compacted granular foundation, the driveway is much more susceptible to settling, rutting, and cracking over time. The original project specifications. The agreed-upon base depth and asphalt thickness. An explanation of why the driveway was installed directly over native soil. If the work does not match your contract or accepted local construction practices, it may be worth having the driveway inspected by an independent paving professional before making your final payment.