Can I do the paving on my existing yard or do I have to excavate first?

Evaluate the foundation

In the case of an existing unpaved driveway, it must be ensured that the foundation is acceptable to support the paving, as it is a semi-flexible coating.

Option 1: non-existent foundation

Option 2: foundation deficient in places (roulière, pothole, beef belly, etc.)

Option 3: good foundation

Verification can be done visually and/or by excavation. Ideally, a foundation should be draining, uniform, free from large stones, and drained into the street or other foundations. An existing yard that does not have a major problem should have an acceptable foundation for paving. The more homogeneous the foundations of a yard, the more uniformly it will move, and therefore less risk of cracking. Be careful, just because you can’t see your gravel moving doesn’t mean your yard isn’t moving. When there is paving with a smooth surface, the deformations will appear more! Making holes in the yard to verify its composition leads to certain problems: who will pay to perform this task? This action will create reworked areas (weaknesses),

For economic reasons, many customers prefer to take the risk of correcting only the most problematic places and paving over the existing foundation. This option is more economical, but it increases the risk of cracking. On the other hand, excavation and foundation work over the entire surface increases by approximately 2.5 times the price compared to that of paving alone. When the client makes this decision (not to excavate the entire yard), he assumes responsibility if cracks, rollers, or the like appear in the paving. An enlargement may behave differently from the existing part, which may lead to a different displacement and a crack.

In many cases, this option is beneficial to customers, as the price difference offsets the risk.

Paving on the existing foundation:

When the choice to keep the existing foundations is made, it may be, after the start of the work, that this choice must be modified because of the problems that we may encounter. Example: the yard is much too soft. In some cases, you can wait until it becomes hard or softer again, but then the paving work will be more difficult to do and there is a risk that marks will remain on the paving. No one can predict the longevity of paving under these circumstances!

It is important to remove vegetation, especially large dandelions, and plantains, as their roots can grow back through new asphalt. In both of these cases, it is best to kill them before proceeding with the work. Be careful, herbicides normally need the leaves to be able to act effectively. The removal of vegetation, and unwanted material (earth, mud, clean stone, large exposed stone, etc.) is done at the beginning, it is called “decontamination.”

Then we proceed to level from the courtyard. This step is used to remove or add as needed material to adjust the slopes of the yard, to get the water out of it and ideally send it to a favorable location. Avoid sending water to the house or any other place where the water could cause breakage: sagging, swelling due to freezing, etc. During this step, the team will compact the material, approximately one to three times as needed. Combined decontamination and levels are the steps that take the most time to be able to do a good paving job. The asphalt thickness should then be uniform over the entire surface. After this work, you will be able to see the thickness to be filled by the asphalt, particularly if you have a garage, door sill, sidewalk, etc. The edge of the street may be different, because we try to get higher than the street to prevent water from entering the courtyard. So the measured thickness may be less compared to the street.

Need for excavation:

When excavation is required, we prefer 450 mm (18 inches) to 600 mm (24 inches) deep with a bottom foundation of crushed stone 0-50 mm to 0-112 mm (0-2 inches to 0-4 inches) ) and a top foundation of 0-20 mm (0-3 / 4 inch) crushed stone. Crushed stone is more stable than sifting sand or gravel because the stones have ridges instead of round. For 450 mm, we prefer to put a membrane underneath. If you are offered a higher excavation depth, be careful, this is not always good, because if your excavation is in a non-training environment and you are deeper than the place where you can get the water out; then it will stay in your yard, freeze, and warp it. Take care, the water does not just circulate on the surface,

The bottom of the excavation must be smooth and must be able to drain water, usually in the foundations of the street. In the event that the bottom of the excavation is unstable (soft, with clay, etc.), it is preferable to put a membrane to avoid contamination of the foundations and increase their resistance. The material should be compacted to a maximum of every foot of thickness (0.3 m).

When expanding, it is best to excavate to the same depth, especially if the new part drains into the existing part.

Get in touch with a professional

With our qualified professionals, you are guaranteed to obtain a final result of the highest quality and lasting. Our work is always carried out with meticulousness and respect at Skye Asphalt. We are constantly rewarded for the quality offered to our customers.

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