You cannot just place driveway pavers down on top of your old driveway, as convenient as that would be. Instead, the concrete or asphalt that you have needs to be pulled up (unless you’re so lucky as to be starting off with a gravel driveway). And then, you need to put down base material, which is typically crushed stone, sand, or sometimes stone dust. Here’s what you need to know about preparing your driveway surface for paver installation.
This advice applies to all kinds of paver driveways, including interlocking pavers, brick driveways, and most other types of paver masonry. It does not apply to poured concrete driveways.
Why Can’t You Place Pavers on Asphalt or Concrete?
We get it: it would be so much more convenient to simply build your new paver driveway on top of your old one. But there area few problems with that. Firstly, the new driveway would be higher than the road, which would mean you couldn’t drive up onto it. Even if you were to build a ramp, placing the pavers right on asphalt or concrete is still a bad idea.
As the weather changes, asphalt and concrete are stressed. They crack and move, and when they do so they would move and crack anything above them. The whole point of getting a paver driveway is that it is more durable and consistent than an asphalt or concrete driveway, so keeping that material significantly undermines the pavers.
Don’t Just Use Sand
While just sand may be an ideal material for beneath pavers in other spots, a paver driveway needs something more stable. Heavy traffic inflicted by large vehicles can shift even well-tamped sand and create problems with the driveway. Ideally, you would add crushed stone instead.
Specifics of your stone type and layer should depend on the specific nature of your driveway project and the slope of the ground you’ve installed it on. However, stone aggregates such as limestone, dolomite and granite are good choices. Typically, you want ¾ inch gravel pieces to allow for proper drainage and support of the pavers.
You should not use stone dust. This very finely crushed stone is too fine and acts too much like sand, shifting as one under pressure from larger vehicles. Having some stone dust in a ¾ inch mixture is normal, but using just the dust or “screenings” will not work.
What About Recycled Concrete Aggregate?
We use a lot of concrete, and recycling it is wise and more environmentally friendly than mining new stone. So, you may see recycled concrete aggregate pitched as a more environmentally friendly alternative to gravel mixtures. However, concrete acts less predictably under pressure than stone, and it is challenging to assess the quality of recycled concrete aggregate. You may be getting a worse base for your driveway if you choose this material.
While this is a good overview, climate, drainage and use of the driveway all matter when you’re choosing what material to put beneath your driveway pavers. You should work with the professionals to get quality advice on the specific base you should you for your driveway.