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How to Properly Excavate for Your Paver Project

Whether you’re installing a new paver driveway, walkway, patio or retaining wall, proper excavation is a crucial first step. It must be done safely and efficiently so each next step can occur as planned. After all, regardless of what your project is, the ultimate stability of the structure relies on its foundation.

Before excavation can begin, you or your landscape contractor will have the presence of buried utility lines located and obtain any necessary permits. Your contractor will mark the locations of the underground gas and phone lines, and stake out the contours of the project’s footprint. Then, it’s time to dig in!

A bit of a mess – but it’s worth it

No two excavation jobs are exactly alike, but the installation of a paver patio, driveway or long retaining wall invariably involves some upheaval, equipment noise and the moving of dirt or removal of debris. It’s wise to speak with your contractor and your neighbors before digging starts to avoid unexpected surprises.

The labor and equipment required for the project will be dictated by the terrain and what is being excavated — whether it’s an old concrete walkway or driveway, thick clay soil or loose topsoil.

There may be unplanned-for obstacles too. Digging a few inches into topsoil and clay is one matter; removing an old concrete walkway or patio is quite another. Don’t be concerned if your landscape contractor is thrown a curve ball. Experienced contractors, like Unilock Authorized Contractors, know to expect a few surprises along the way, and how to address them. If you haven’t already, click here to connect with a Unilock Authorized Contractor.

How deep to dig depends on your paver project

The depth of the excavation depends on two things: 1) Soil type – Clay soil requires deeper excavation, while sandy soil requires less. 2) The load weight of your structure – heavy loads like driveways and retaining walls require deeper excavation, and lighter loads like patios and walkways require less.

Load varies dramatically from a walkway to a driveway or from a 2-foot sitting wall to a 12-foot retaining wall. While an excavation depth of 8 inches is required for a walkway or patio, a driveway is likely to require at least 12 inches.

Retaining walls have requirements all their own. The depth required for a retaining wall is generally greater than a pathway — 8 – 12 inches is common, but a lot depends on the height and weight of the wall.

Walls that are truly retaining in nature are frequently built with some setback – that is, each layer of wall stone is slightly offset horizontally from the layer below to create a face ever so slightly sloped away from the front, against the higher terrain. Because of that, the base trench is often well forward of the retained terrain to allow not only for setback, but for a good 12 – 18 inches of gravel backfill to facilitate drainage.

A shorter retaining wall or a sitting wall may be installed without setback; such walls often require a maximum depth of 6 inches. It’s worth noting that anything taller than 3 or 4 feet may merit a more thorough design review by an engineer, and some municipalities have formal engineering requirements for walls as low as 2 feet.

As for the area of the land that will be affected, it will usually be focused on the future location of your landscape features. However, proper excavation may extend 6 inches or more in every direction beyond the intended perimeter of your eventual structure to accommodate additional lateral support or drainage elements.

With the ground preparation complete, your crew will be layering in a gravel base and a 1” bedding layer of sand or tiny stone chips upon which the pavers are installed.

Your vision brought to life

Next comes the installation of the beautiful Unilock pavers and wall systems you selected during the design stage, bringing your outdoor patio project to life.

If you’re looking for design inspiration for your paver feature, visit the Unilock Outdoor Idea Center today.