Asphalt Paving Blog

Why It's Better To Remove A Concrete Driveway Before Laying Asphalt

BudweiserafterOne question we often hear at Wolf Paving has to do with driveway replacement:

“Should I lay new asphalt over an old concrete driveway?”

This is an excellent question, and many homeowners and business owners are asking it. When it comes down to it we recommend asphalt driveways over concrete for three main reasons:

  • It has faster installation 
  • It has better resistance to weather
  • It is more cost-effective

However, if there's an existing concrete driveway, this presents new challenges.

If the question is "CAN I lay asphalt over concrete?" then the answer is "Yes." This is absolutely possible if elevations allow for it, and we're happy to lay asphalt driveways over concrete if that's what you want. It's also the cheaper option since heavy equipment is required to dig up an existing concrete slab.

Nevertheless, there are significant downsides to this. Generally speaking, we recommend removing the existing concrete first, for two big reasons.

1. A Concrete Driveway Sub Base Is Different Than an Asphalt Driveway Sub Base

Concrete Driveway Sub BaseThe big problem with laying asphalt driveways over concrete has to do with the initial preparation of the site.

With concrete, if you're concerned about strength and stability, the solution is to simply lay a thicker slab. Because of this, contractors laying concrete rarely worry about preparing the base. The ground underneath a concrete driveway may be prone to shifting or sinking, and there's really no way of knowing what's down there until it's dug up.

Laying asphalt over concrete creates two layers to worry about:

  1. The unprepared sub base
  2. The concrete itself

If something is wrong with either of these layers, it will show through the asphalt. Unfortunately, when asphalt driveways are poured over concrete resting on an unstable base, the resulting asphalt pour is prone to instability. Expansion joints in the concrete will quickly turn into cracks in the asphalt, which will require costly ongoing repair jobs. In extreme cases, shifts in the ground could crack the entire surface, just as a house's foundation may crack if improperly laid.

2. Pouring Asphalt Over Concrete Is Bad for the Longevity of Your Driveway

So yes, pouring asphalt over concrete may look good at first, but there are bound to be troubles over time. It just doesn't make fiscal sense to do it, as that driveway will need a lot more work in the near future.

Asphalt driveways last longer and look better when they are built from the ground up. Your new asphalt driveway will have a proper, stable base, and therefore will require less maintenance as time goes on, saving money in the long run.

There are some instances where concrete and asphalt work well together, such as curbs and edges. But generally, they work better side by side rather than one on top of the other. For more information about the side effects of paving asphalt over concrete visit this blog.

Wolf Paving Recycles Concrete

Wolf Paving also reclaims and recycles 100% of the concrete we dig up! It goes into our mixers to make more asphalt and base materials, helping reduce the environmental cost of the next asphalt driveways we lay. We also accept materials from other contractors.

To learn more about how we recycle concrete into aggregate, read this blog

If you're interested in a new asphalt driveway, whether there's existing concrete or not, contact us today for a free estimate and consultation!

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Topics: Asphalt Driveway, Residential Paving, Asphalt Questions