Before I answer the question of how tar-and-chip driveways compare to other kinds in terms of cost, durability, maintenance, etc., let me offer a brief introduction to just what this type of driveway consists of. Many of you may not have heard of it before, even though many roads (picture) are paved with this material. As you'll see below, its pros far outweigh its cons, so further efforts on your part to research this subject may well prove worthwhile.
What Is a Tar-and-Chip Driveway?
This type of surface is also called "Macadam," a name derived from its creator, a Scottish engineer named McAdam. As Mary Bellis observes in her biography of McAdam, roads built this way were originally water-bound, before evolving into the tar-based versions we have today. The problem with the water-bound version was that it allowed too much dust to be kicked up, a problem remedied by the use of tar as a binding agent. This evolution accounts for why you may also encounter the term, "tarmacadam," which retains the original "Macadam" while updating it to reflect the improvements that come from the addition of tar. Incidentally, the term has been shortened to "tarmac" and used to indicate an airport runway, although most such runways are now constructed in a different manner.
Here's how tar-and-chip driveways are constructed:
Hot tar (i.e., liquid asphalt) is applied to a gravel base.
So much for the "tar" part. What about the "chip" part? Well, while the tar is still piping hot, stone chips are thrown on top, so that they can adhere to the tar. Since a major selling point of tar-and-chip driveways is their looks, people usually make sure the stone chips are pretty, not just any old stone chips.
For instance, you might want stones that are a particular color. After the stone chips are laid on top of the tar, a steamroller presses them in firmly.
What Are the Pros and Cons of Tar-and-Chip Driveways?
Every driveway material has its pros and cons, and this type is no different in that regard. Let's look at some of them:
- Cost: they are cheaper than asphalt.
- Low-maintenance (just occasionally replace displaced stones).
- The rough surface potentially affords good traction.
- Difficult to find contractors for installation.
- Snow removal is difficult and could even result in damaging the surface.
Besides their splendid appearance, tar-and-chip driveways also cost less than asphalt, nor do they have to be sealed, thus cutting down on your yard maintenance (and, therefore, costs).
Tar-and-chip driveways afford good traction, since the surface layer is composed of individual stones. So rather than having a smooth and potentially slick surface like asphalt, the surface of tar-and-chip driveways is rough. Just make sure you find a contractor who comes highly recommended, because, if not properly constructed, the same characteristic that gives these surfaces traction also makes them more difficult to plow and shovel: namely, all those individual little stones sticking up.
If you wish to be extra-cautious with your tar-and-chip driveway and keep any loose stones in place, instruct your plowing contractor to keep the plow blade up slightly off the surface (hopefully, your contractor follows instructions well). But unless you plan on having that leftover one inch or so of snow melt off pretty soon (as it might on, say, a south-facing slope), you may be losing some of that good traction for which tar-and-chip driveways are known. In New England, where I live, an inch of snow can stay around for a long time (especially on a flat surface), and it will generally ice up -- creating a hazard.
Tar-and-chip driveways can be a beautiful addition to your landscape. Commenting on the durability of Macadam, This Old House mentions an additional advantage to tar-and-chip driveways, remarking that oil leaks can be rather easily hidden.
Finding a contractor to install one, however, may be a challenge, as tar-and-chip driveways are not nearly as popular as asphalt paving.
Thanks to Daly Paving for advice about tar-and-chip driveways.